Self Help Manual Of 1 Story Buildings

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MICROFICHE
REFERENCE
LIBRARY
A project of Volunteers in Asia
Self-Heln Construction of l-Storv Buildins
Peace Corps ATFD Manual M-6
by:
Peter Gallant
Published by:
Peace Corps
Information Collection and Exchange
806 Connecticut Avenue, NW
Washington, DC 20525 USA
Available from:
Peace Corps
Information Collection and Exchange
806 Connecticut Avenue, NW
Washington, DC 20525 USA
Reproduction of this microfiche document in any
form is
subject
to the
same
restrictions as those
of the original document.
APPROPRIATE TECHNObOGlES FOR DEVELOPMENT
of l-Slow Builtlimgs
S
INFORMATION COLLECTION & EXCHANGE
MANUAL NO. M-6
INFORMATION COLLECTION AND EXCHANGE
Peace Corps' Information Collection and Exchange (ICE) was
established so that the strategies and technologies developed
by Peace Corps Volunteers in their field work could be made
available to the wide range of development workers who might
find them useful. Training guides, curricula, lesson plans,
manuals and other Peace Corps-generated materials developed
in the field are collected and reviewed: some of these ma-
terials are reprinted; others provide an important source of
field-based information for the production of manuals or for
research in particular program areas. Materials that you
submit to the Information Collection and Exchange thus become
part of the Peace Corps' larger contribution to 'development.
A listing of all Information Collection and Exchange publi-
cations is available through:
Peace Corps
Information Collection and Exchange
OZfice of Programming and Training Coordination
806 Connecticut Ave., N.W.
Washington, D.C. 20525
ICE Reprints, Manuals, and Resource Packets are available
on request to Peace Corps Volunteers and staff. On a limited
basis, most are also available to field workers in developing
nations. Others who may be interested in obtaining these
materials may purchase them through National Technical
Information Service, 5285 Port Royal Road, Springfield,
Virginia 22161, and a few selections are available
through Volunteers in Technical Assistance (VITA), 3706 Rhode
Island Avenue, Mt. Rainier, Maryland 20822.
Add your experience to the ICE Resource Center: send
materials that you've prepared so that we can share
them with others working in the development field. Your
technical insights serve as the basis for the generation
of ICE manuals, reprints and resource packets, and also
ensure that ICE is providing the most updated, innovative
problem-solving techniques and information available.
SELF-HELP CONSTRUCTION
OF l-STORY BUILDINGS
Written by
Peter Gallant
illustrated by
Nancy Bergau
edited by
Jim Seaton
Peter Hunt
Peace Corps
Information Collection and Exchange
Manual M 6
Special Printing
for AID Resources
December, 1980
Self-Help Cons&.&ion of I-Story Buildings is the sixth in a series
of publications being prepared by the United States Peace Corps.
These publications combine the practical field experience and
technical expertise of Peace Corps volunteers in areas in which
development workers have special difficulties finding useful
resource materials.
PEACE CORPS
Since 1961 Peace Corps Volunteers have worked at the grass roots
level in countries around the world in program areas such as
agriculture, public health, and education. Before beginning
their two-year assignments, Volunteers are given training in
cross-cultural, technical, and language skills. This training
helps them to live and work closely with the people of their
host countries. It helps them, too, to approach development
problems with new ideas that make use of locally available
resources and are appropriate to the local cultures.
Recently Peace Corps established an Information Collection &
Exchange so that these ideas developed during service in the
field could be made available to the wide range of development
workers who might find them useful. Materials from the field
are now being collected, reviewed, and classified in the
Information Collection & Exchange system. The most useful
materials will be shared. The Information Collection & Exchange
provides an important source of field-based research materials
for the production of how-to manuals such as SeZf-Help Constmction
of I-Story Buildings.
THE AUTHORS
Pete Gallant served as a Peace Corps Volunteer in Liberia for
three years. During that time he worked on and supervised a
variety of projects involving the construction of l-story
schools,
roads, and bridges in rural areas. Mr, GaLlant-holds a Bachelor
of Arts degree in Political Science from St. Joseph College; he
is now working with the U.S. Department of State.
(iii)
Peter Hunt workes for several years in the audio-visual and
training departments of Save the Children Federation where he
worked on materials to help field workers promote cornmunity-
directed construction projects. He is now a free-lance video
producer and develops video- and print-based training materials
for national and international organizations.
Jim
Seaton is Co-Director of Communications Development Service
(CDS), an independent organization that provides field training
for development workers. He specializes in designing materials
and informal educationalexperi.?nces that help community members
focus on their own knowledge, experience, and human resources
as the basis for self-development. -Mr. Seaton is currently
developing training workshops in nutrition planning for several
countries to help government staff respond effectively to
community initiatives in integrated rural development.
Nancy Bergau, the graphic artist for this manual, served with the
Peace Corps as a graphic design consultant to the National
Broadcast Training Centre and TV Pendidikan (Educational TV), both
in Malaysia. Before joining Communications Development Service
to work on this manual, she also worked as art director for a
multi-media public health education program. Ms. Bergau has
extensive professional experience with the full range of graphics
and audio-visual production. Her illustrations proved invaluable
in shaping the manual's text and in making the more complex
technical details easier to explain.
Many thanks are due here to a number of people who aided the
preparation of this manual:
Henry Baker, Director, Santa Cruz City Department of Parks and
Recreation, Santa Cruz, California.
Steve Bender, Consultant. Program Director, Rice University
Center for Community Design and Research, Houston, Texas.
Tom Callaway, Director, Division of Technology and Documentation,
Office of International Affairs, Department of Housing and Urban
Development, Washington, D.C.
Earl Kessler, Self-Help Construction Advisor, Foundation for
Cooperative Housing.
Special notes of thanks are due to:
Brenda Gates, for her continued support as Project Director of
the Peace Corps Program and Training Journal Manual Series.
Karen Seaton, Communications Development Service, for her lay-out
work andproduction assistance with this manual.
(iv)
For your convenience, a reply form has been provided here. Please
send it in and let us know how this manual has helped or can be
made more helpful. If the reply form is missing from your copy
of the manual, just put your comments, suggestions, descriptions
of problems, etc., on a piece of paper and send them to:
SELF-HELP CONSTRUCTION
Peace Corps
Information Collection & Exchange
806 Connecticut Avenue, N.W.
Washington, D.C. 20525
U.S.A.
w
PLEASE RETURN THIS FORM
NOTE TO USER: This manual was published because Peace Corps
workers and volunteers wish to help in a growing area of worldwide
interest. In order to provide the most effective help, the
preparers of the manual need to know how it is being used, or how
you feel it could better serve your needs. Please fill in the
followinq form and return it to:
SELF-HELP CONSTRUCTION
Peace Corps
Information Collection & Exchange
806 Connecticut Avenue, N.W.
Washington, D.C. 20525
U.S.A.
WHEN WE RECEIVE THIS FORM, WE WILL AUTOMATICALLY PLACE YOUR NAME ON
A MAILING LIST SO THAT YOU WILL RECEIVE:
. Updates and/or additions and corrections to the manual as they
become available.
. Notice of other publications w'nich may be of interest to you.
If you have questions on the material presented in the manual, or if
you run into problems implementing the suggestions offered here,
please note them in the space provided. Use additional paper if you
have to in order to be as specific as you can about the problem.
Wherever possible, we will try to provide, or direct you to, an
answer.
Your Name
Your Address
* * *
Date
Your Company or
Agency, if any
1. How did you find 0u.t about the Peace Corps SeZf-HeZp Construction
of I-Story BuiZdings manual? How did you get your copy?
(vii)
2.
3.
4.
5.
6.
7.
Which parts of the manual have you found most useful? Least
useful? Why?
Did you find the manual easy to read, too simple or complex,
complete or incomplete?
How has this manual helped your work? What have you done to
apply the information?
Can you recommend additional methods or equipment which you
feel'should be included in a new edition of the manual? If
you know of such methods, etc., please include the information
here.
What were your successes using the manual or implementing any
of the ideas or procedures? Problems? Please describe
completely.
Do you have other recommendations?
Privacy Act Notice: Furnishing the information requested herein is
completely voluntary. It is requested under authorities contained in
the Peace Corps Act (22USC 2501 et seq.). The only uses which will be
made of this information are as follows: 1) For management purposes
involving the format of future issues of this publication; 2) For in-
corporation in a mailing list for this and other
similar
publications.
TABLE OF CONYENTS
Page
About This Manual . . . . . . . . . . . . . . . . . . . . . . . ..“................. iii
ReplyForm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..~~...........~..vii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
A Note on the Development Process and Construction
Projects....................... . . . . . . . . . . . . . . . . . . . . . . . . . . 3
How To Use This Manual................................,....5
What This Manual Will Talk About . . . . . . . . . . . . . . . . . . . ...*.*.. 6
1 BASIC PLANNING AND DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . -11
Site and Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
How Big Should the Site Be?..........................1 4
How Accessible, and How Private Should the Site Be?..1 6
What Kind of Soil Should the Site Be On?.............1 8
How Well is the Site Drained?........................1 9
'\ How Should the Building Be Placed on Its Site?.......2 0
', Summary of Factors Affecting Site Selection..........2 1
Size, Shape, and Floor Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
"..School s .............................................. 22
Clinics .............................................. 25
Homes ................................................ 27
What Size Will Each Room Be?......................3 0
Using Measuring Units to Help the Family Plan
Its Own Floor Plan ............................... 31
Helping the Family Draw Its Own Floor Plan........4 1
Drawing the Floor Plan of A House.................4 2
Doors, Windows, and Ceilings In All Buildings........4 8
Where Will Inside Doors Be Placed?................4 8
How High Will the Ceiling Be?.....................5 1
Where Will Windows and Outside Doors Be Placed?
How Will They Be Designed, and What Size Will
They Be?. ........................................ 52
Windows in a Tropical Climate.....................5 3
Protecting the Inside of the Building From Rain
and Insects ...................................... 56
Taking Advantage of Any Breeze....................5 8
Windows in A Desert-Like Climate..................6 2
Exterior Doors .................................... 65
Construction Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...*.*
66
Rammed Earth (Mud, Pise) and Adobe Bricks............67
(ix)
Page
Wood .................................................. 69
Bamboo ................................................ 69
Stone/Rock ............................................ 70
Cement and Materials Made With Cement.................7 0
Mortars...............................................~
Concrete ...............................................
Reinforced Concrete...................................7 2
Blocks ................................................ 74
Concrete Blocks.......................................7 5
Sand-Cement Blocks (Sandcrete)........................ 5
Stabilized Earth Blocks...............................7 6
Summary ............................................... 76
2 DETAiLED PLANNING FOR CONSTRUCTION.. . . . . . . . . . . . . . . -79
~
Planning Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 2
Footings .............................................. 83
Foundation Walls ...................................... 84
Deciding Upon the Materials and Dimensions For
Foundations ..........................................
88
Drawing Final Foundation Plans........................8 8
PlanningFOoors...........................................9 0
Types of Floors. ...................................... 90
Planning Walls, Windows, and Doors ......................
92
Wall Height and Length ................................ 93
Wall Thickness ........................................ 94
Placement of Doors and Windows........................9 5
Construction Details for Doors, Windows and Interior
Walls ................................................ 96
Planning Roofs ..........................................
101
Roof Styles and Their Functions......................l-- t
Roof Materials .. ...... ...............................
Construction Details For Roofs.......................10 7
3 DIRECTIONS FOR CONSTRUCTION .........................
115
Setting Out iLaying Out). ................................ ,116
Orientation .......................................... 119
Marking
the Foundation Outline.......................12 0
Batter Boards ........................................ 123
(x)
4
Page
Construction of Foundation Footings . . . . . . . . . . . . . . . . . . . .
127
Digging the Foundation Trench........................12 7
Formwork For Footings................................12 9
Making the Concrete For Foundation Footings ......... .I30
Pouring the Concrete For Foundation Footings.........13 5
Curing the Concrete For Foundation Footings..........13 6
Reinforced Footings..................................13 7
Construction of Foundation Walls . . . . . . . . . . . . . . . . . . . . . . . ,138
Concrete Foundation Walls............................13 8
Block Foundation Walls ............................... 140
Making Blocks.....................................14 0
Making Concrete Blocks.........................14 0
Making Sand-Cement Blocks......................14 1
Kaking Stabilized Earth Blocks.................14 5
Laying Blocks ..................................... 148
Finishing the Mortar..............................15 1
Rock Foundation Walls................................15 1
Construction of Floors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
153
Earth Floors ......................................... 153
Concrete Floors ...................................... 154
Construction of Walk, Windows, and Doors ............. ,157
Block and Brick Walls ................................ 157
Making the Blocks or Bricks.......................15 7
Blocks With Cement Content.....................15 7
Adobe Bricks...................................15 7
Laying Blocks and Bricks .......................... 160
Framing Windows and Doors.........................16 4
Roof Preparation..................................16 6
Rammed Earth Walls...................................16 9
Earth Mixture ..................................... 169
Forms ............................................. 170
Procedure.........................................l7 0
Framing Windows and Doors.........................17 1
Roof Preparation. ................................. 172
Construction of Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
172
Flat Roofs ........................................... 172
Shed Roofs ........................................... 173
Gable Roofs..........................................l7 6
(xi)
Page
4 CONSTRUCTION WITH BAMBOO ..........................
181
Bamboo For Foundations .................................... 183
Bamboo For Frames. ........................................ 183
Bamboo For Floors. ........................................ 185
Bamboo For Walls .......................................... 186
Bamboo For Doors and Windows .............................. 187
Bamboa For Roofs..........................................18 7
Bamboo Reinforcement of Concrete..........................18 8
Preservation of Bamboo. ............................. ... """18 8
5 LATRINES
............................................... ..18 9
Location of Latrines ...................................... 190
Pit. ................................................ ... """19 1
Base ...................................................... 192
Floor ..................................................... 192
Shelter.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
6 CONSTRUCTION llh EARTHQUAKE AREAS .................
195
Selection and Preparation of the Site ..................... 196
Selection of Building Materials ........................... 198
Reinforcement of Buildings ................................ 198
APPENDICES . . . . . . . . . . . . . . . . ..“....““.“.““.“.““......“..“....
201
Calculations to Check Whether a
Proposed Site will
Support a Building............ 202
. . . . . . . . . . . . . . . . . . . . . . .
2. Step-By-Step Directions For Drawing Foundation Plans...218
3. Estimating the Amount of Concrete Needed For a Floor...215
4. Estimating Materials Needed To Build Walls.............217
(xii)
Page
_. Reference Tables for Concrete Construction.....,........221
r;
6. Metric Measurements Used in This Manual and Their
U.S. Equivalents.........................,............225
7. Sources of Further Information..........................226
8.
"Human Measuring Pieces" For Designing Room Size and
Floor Plan............................................231
(xiii)
INTRODUCTION
This manual has been designed to
help field workers with little or
no construction experience assist
a community or family to
*plan and ,&sign a l-story
community building (such as a
school or health clinic) or home
that fits their present and
future needs,
*assess the advantages or dis-
advantages of locally available
construction materials,
-draw and understand their own
construction plans: and
FLOOR PLAN: VIEW OF A BUILDING FROM
.successfully complete construction
according to their own plans.
ABOVE
SIDE VIEW OF THE SAME BUILDING
The
aim is
to present the construction process in three basic steps:
1) first, exploring the needs of the people who will use a
building and arriving at a
basic design
that will fill as
many of those needs as possible; the basic design includes
decisions about the number and size of rooms, the arrange-
ment of the rooms, the major construction materials that
will be usedl and the choice of a site for the building;
2)
second, working out a detailed, written construction plan
for each part of the structure, from the foundation to the
roof;
3) third, actually constructing the building according to plan.
In its technical sections, the manual focuses on basic principles
of construction with materials that are low-cost, available in many
parts of the world, and easy to work with. In any given locale or
climate, different materials (or combinations of materials) will be
available--or suitable. But understanding the construction
principles covered here should help the field worker work with
self-help groups to adapt the specific step-by-step suggestions to
whatever materials are available to them.
No book could hope to cover all design and construction problems
or situations. This manual presents some of the most widely used
innovations in local materials and design. But in many cases, field
workers and communities will need to adapt these ideas tc conditions
at the project site. The Peace Corps Information Collection &
Exchange hopes to incorporate such local adaptations in future
supplements to this manual,. Any comments, suggestions, or new ideas
are most welcome. Please send information about your construction
project's experience to the address on page (v).
One final note: the essentials of the construction process are well
within the understanding and skills of community groups. But the
field worker should always have one or more advisers in mind who
can be contacted if problems arise during construction. In any
projec-t, no matter how simple, unforeseen difficulties or special
conditions may pose problems that this manual does not cover. We
have tried to indicate those areas, especially during the planning
of a construction project, in which assistance from someone
experienced in local construction problems may be needed. In
addition, the bibliography at the end of the manual lists other
valuable sources of more detailed information in Appendix 7.
A NOTE ON THE DEVELOPMENT PROCESS AND CONSTRUCTION
Few things can inspire a community or family more than seeing
and using a building that they have built together. In fact,
getting a community to cooperate on a simple construction project
is one of the best ways to help them start tackling their difficult
development problems.
But not all construction projects are effective. In thousands of
communities all over the world, schoolsl clinics, and homes have
been built for people and thenlzever
used,
because the design of
the building was unacceptable to the people, because the community
could not afford to operate it and felt no sense of ownership,. or
because the building didn't fit the community's priorities.
When thinking about a construction project, therefore, the field
worker should remember that the
imediake
improvements he/she hopes
will result from a new building are less important than the community's
participation in planning, budgeting, constructing, and then using
a new building itself. The experience of working together on a
project can lead to increased interest and confidence in further
community-managed development efforts. But simply watching while
a building is planned and built by others can seriously hurt community
confidence and provoke hostility to development efforts.
The community or family must be (and must recognize themselves as) the
key actors in all stages of a construction project. But the field
worker still has a crucial role to play in the process. The field
worker can function:
1) as an initiator of the project,a
non-formal educator, and a
catalyst for decision-makinq.
Where traditional approaches or
solutions are not serving
community members well enough,
the field worker can help them
explore and define their own
needs/solutions from a new
problem-solving view-point.
There are organizations in
almost all countries that
provide information and
training in techniques that
promote this exploration
process.
247-811, 0 - 77 - 2
4
2)
3)
as a planning assistant. Once a community has decided to build
a home, school, or &lxic, the field worker can provide valuable
information and assistance to help them design the building,
purchase and assemble materials, and organize the construction
process. This manual is designed to provide basic technical
information the field worker needs to help a community.
as a project fund-raiser. Community groups have limited access
to the funds needed for small local projects. The field worker
generally has much greater knowledge of, and contact with,
government, private, and international agencies that could
support a community project. The Information Collection and
Exchange publishes a manual,
Recources for Development Agents,
that
may be useful for field workers trying to get technical or
financial help. The manual talks about analyzing resource
needs and gives names and addresses of organizations that
provide those resources. For a copy, write to:
Peace Corps Information Collection & Exchange
806 Connecticut Avenue, N. W.
Washington, D. C, 20525
U. S. A.
In addition, Peace Corps Partnership Program can be a source of
funds to support small community construction projects. Grants of
$1,000 to $5,000 are made to communities that have initiated
their own project, plan to use volunteer labor, and donate
25% of all materials. For information'*and application forms,
write to Director, Peace Corps Partnership Program, at the
address above.
SUCCESS OR FAILURE?
Once the decision to build has been made, the field workerls main
concern should be to ensure that the community's self-help efforts
succeed.
Success depends on several factors:
* Those who will ultimately use the building should be actively
involved inevery stage of the project---from conception to
planning to construction: their needs, desires, and budgetary
restraints should be decisive in all planning issues; and the
project must depend on their desire to pursue it. The
field worker should never be the actual leader of the
project. He/she should provide assistance, not direction.
* The building plans should be simple, and affordable. As
far as possible, the construction materials should be locally
available.
* The completed building must be useful: it should have
adequate space for its intended use and it must be comfortable,
healthful, and attractive. Space for future additions or
needs should be planned for.
How to Use This Manual
DISCUSSION
For the most part, this manual presents information that
anyone planning a simple construction project needs to have.
By reading each section thoroughly in sequence, field workers
can prepare themselves to assist community groups that n.=ed
technical assistance. The sections can also be referred to
individually at any time specific information is needed during
construction.
ILLUSTRATIONS
There are illustrations throughout the book designed to make
the process easier to visualize. Field workers will find that
using these illustrations with the community/family will help
these groups understand the field workers' suggestions.
PLANNING EXERCISES
In Section 3: Basic Planning and Design, there are suggested
exercises with paper cut-outs that a family or community group
can work on together i.. order to design the size of each room
they need, and the floor-plan (the arrangement of the rooms) of
the building. These are most effective when the field worker
is present to help the group explore their needs thoroughly and
to help them prepare the cut-outs.
5
What This Manual Will Talk About
Basic Planning and Design
To have a reasonable chance of success, any construction pro-
ject must be carefully designed to ensure that the completed
building:
* can be built with the budget and resources available;
* will fill more of the present needs of those who will use it;
* is designed and placed with future needs in mind without
abandoning the original structure (for example, if more
space will be needed two years from now, can it be added on
the present site?).
CAN THE PROJECT BE BUILT WITH THE BUDGET AND RESOURCES AVAILABLE?
Five things affect a self-help gro_upls ability to complete a
construction project:
l
availability of construction materials
0 money
l
time
l
labor (for construction and maintenance)
l
organization
Availability of Construction Materials.
construction materials available. There are many different
Denending on local conditions
such as climate and supply, each one is-suitable for different parts
of a building. Each has advantages and disadvantages in terms of
suitability, cost, time, labor, and durability. A family or
community should understand the basic characteristics of all
available materials in order to make the best possible choices to
fill their needs.
Money is needed in construction projects to buy and transport any
materials that are not available near the construction site. costs
can be significantly reduced by using locally available materials.
In most areas,
supplies. almost the entire building can be built from these
However, care must be taken to choose materials that are
durable and safe. Materials fcr some parts of the building,
especially the foundation, may be worth purchasing, even if
financing is difficult.
Time. Different construction materials require different amounts of
time to prepare and assemble. Some can only be used in certain
seasons. Thus the choice of materials, building design, and
schedule of work, all depend on how much time is available for
construction.
7
Labor. Different materials require very different amounts 'and kinds
of work. Some parts of a structure-- especially certain roof designs
--require many more people than others, or people with different
skills. So, the number of people who can work on a project, their
level of skill, and the time they can devote to the project must
be considered while planning construction.
%%%%%iat~~~~ %o~~~~$~s, doors, windows, and roof.
t building has many different parts,
These
must often be built in a certain order (for example, the walls
usually can't be built before the foundation). In addition, each
part may be made from several materials that must be put together
carefully and in a precise order. For work to go smoothly, the
builders must be able to organize the project: to estimate in
advance what materials will be needed, how much of each will be
needed, and to bring the correct supplies to the site at the right
time. Many projects fail because a vital material is not ordered
in time and all work must stop until it arrives--sometimes too long
a wait for work to begin again.
WILL THE BUILDING FILL MORE OF THE PRESENT NEEDS OF THOSE WHO WILL
USE IT?
All build2ngs should be durable, healthful, and comfortable. In
addition, other considerations should be kept in mind by a community
or family designing a building.
A community planning a clinic or school must consider many different
needs. For example, a clinic would have to have space for treating
patients, for people to wait before they are treated, and perhaps
space for one or more people to stay overnight while recuperating.
These would be the primary needs. However, the community might also
desire to use the clinic for educational purposes: health education,
for example, or nutrition classes. The most effective design would
depend on aZZthe planned uses of the building.
A family needs to plan enough space for all family members. The
family must decide how many rooms they need, what kinds (dining,
sleeping, etc,) and what size. Other needs may include ease of
movement, storage space, privacy, etc.
IS THE BUILDING DESIGNED WITH FUTURE NEEDS IN MIND?
Present needs may change soon:
l
there may be many more students in the school 3
years fromnow; or the community may start holding
meetings in the school next year;
l
a doctor may move into the community and need
living space near the clinic;
l
a family may grow and need more room.
8
Future needs like these can be difficult to fill if the building is
constructed next to something (like a river or road) that will block
future construction; or if it is designed in a way that makes
additions impossible. The easiest way to ensure that a building will
be useful throughout its lifetime is to anticipate future needs and
plan so that they can be filled easily by adding to the present
design whenever they arise.
SITE SELECTION AND POSITION
In addition to a building's design, where it's located (the site) and
which direction
it faces (the.position) are crucial to its success.
Four factors must be considered in choosing the best site and
position:
*location: Will a school, ,for example, be relatively easy for
all students to reach? Can construction materials be brought
to the site easily?
*terrain: Is the land hilly or flat? hard or soft? well-
drained or marshy? subject-to earthquake? All these factors
affect building design, safety, and comfort:
*Size of the plot: Is there enough land for the building?
Is there room for future additions to the building?
*Climate: The temperature, prevailing winds, and rainfall all
affect the comfort and healthfulness of a building. And the
posit&n of a building is crucial in helping to control the
environment inside the building.
Detailed Nanning and Directions Qor Construction
Buildings have 4 basic parts:
l
footing and foundation
0 floor
l
walls, doors, and windows
l
roof
Section 2 of the manual contains the information needed to draw
plans for each of these parts. Section 3 contains step-by-step
guides for the actual construction: that is, how to work from
written plans to complete a structure that will last a long time
and require a minimum of maintenance.
FOUNDATIONS
The foundation of a building
provides a level base for the
structure to stand on. It must
be strong enough for the building
that sits on it; it must be level
and plumb (straight up and down);
and it must be secure from
damage by water, frost, settling
earth, and earthquakes.
FLOORS
Floors provide a secure, level,
and comfortable surface for
everything inside a building.
They must be far enough above
,ground level to remain dry, easy
to keep clean, non-slippery, and
level (so that objects do not
roll or slide).
WALLS, DOORS, AND WINDOWS
Walls provide privacy and shelter from the elements.
hold up the roof. They also
They must be thick enough to protect the
inside from heat or cold, strong enough to support the roof and
withstand wind pressure, and high enough so that people can stand
comfortably without hitting their heads on the ceiling.
Doors and windows provide light and ventilation. In addition,
doors (or doorways) allow people to move in and out of the
building and between rooms.
only as much light, air, They must be designed to allow
building; cold, and heat as desired into the
at the same time, they must keep insects, dirt, and rain
outside and provide privacy when closed.
ROOF
The roof protects a building from rain,
and insects. snow, wind, cold or heat,
It must be designed to withstand wind pressure, and
the weight of anything that might fall on it. In addition, care
must be taken to ensure that community members will be able to
build the roof (the parts cannot be too heavy to lift).
Latrines
Latrines are important to good
heal,th because they can
eliminate diseases spread
through human excrement.
They should be included in
the planning of any public
building or home. Special
rules apply to their
location, positian, and
construction. See Section 5,
page 189.
Earthquakes
Earthquakes place severe stresses on' buildings. But there are many
methods of construction, principles of design, and materials that
can help a building withstand tremors--at least long enough to
allow occupants to escape safely. Most of these earthquake-
resistant techniques cost nothing at all, or are very inexpensive.
Builders in earthquake zones can and should use these techniques
even when their budget is limited. See Section 6, page 195.
BASIC WANNING AND DESIGN
Before construction can begin--
can be or detailed plans for construction
drawn-- the builders need to consider three basic planning
and design questions:
SITE AND POSITION
o What land will the building be
constructed on?
o Where on this site will the
building be placed?
SIZE, SHAPE, AND FLOOR PLANS
0 HOW many rooms will the family
or comraunity need?
l
What size will each room be?
l
How will each room be placed
in relation to the others
(that is, what will the floor
plan be)?
What shape will the building
' be? Round? Rectangular?
Some other shape?
. How high will the ceiling be?
l
Where will doors and windows
be?
-1.
I..
*:
“
2;
:
13
CONSTRUCTION MATERIALS
. What will the foundation and
floor be made of?
e What will the walls, windows,
and doors be made of?
o What will the roof be made
of?
There are a number of simple guidelines that anyone planning a
building can follow in answering these questions. But it is
important to treat them as guidelines and not as hard and fast
rules. There are rarely any "right" answers. Those who will use
the building must be prepared to find compromises between their
needs and budget on the one hand, and the limitations of local
climate, soil, geology, and construction materials on the other.
This section of the manual is designed to help the field worker
and community member(s) work together step-by-step to answer the
three basic planning questions above for schools, health clinics,
and homes. By following the process sugg?si:ed, the builder
will end up with an accurate picture of what his or her building
will be like.
Here are some of the things planners
might want to leave space for:
Schools
- a shaded outside area for
assemblies, lunches, outdoor
classes
- recreation area for sports,
play
- future classrooms
- other additions such as
offices, library, theatre,
school garden
- compost pile
- livestock/poultry pens
- two or more latrines at least
17 meters from water supply
- cistern/well
- lodging for teachers
- storage for school and
maintenance supplies
Health Clinics
- future additions for extra
reception and treatment
rooms
- cooking area for patients
who must stay in clinic
- latrines
- well
- lodging for health workers/
doctors
- separate building for
maternity care and
recuperation
H0m.e s
- outdoor latrine
- garden
- livestock/poultry pens
- future additions to the home
- well
15
I .~.~.I.-.-.B.~.-.~.I. I
.
’ GARDEN
I r
--- I
I
I
FUTUIRE-EXPAN~ I ON
i
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.
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*
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.
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.A ’
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UTURE MEETING ARE
I
DMS ! I
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I
LATRINESM 0 i
.
i .a.-.lr~I.-.II.I.-.-.-.
.
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.
i
LATRINES
.
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, r--F;-&---l
!i RECUPERATION
I --Y-III-- 1
Y-I------
SMALL -CLIN I C
Many of these needs may appear far-
fetched to the family or community
when they first plan their building
project. However, the field worker
should urge them to allow room for as much future. expansion as
possible. It is always easier to add to a present building and
site than to start over again because there is no room at the first
site.
16
Even in cases where the family or community cannot afford a large
cr,.ough *
site gi3x al1 fiitilre needs, theycm consider what land next
to their site might be obtained for later expansion.
In addition to the actual size of the site, planners need to
consider other conditions at the site that might block future
expansions:
. rivers, streams
. heavy forest or bush
. unsuitable land
marsh)
. roads, markets,
buildings
(such as
existing
Whether these obstacles are on the projected site itself, or on
the land next to it, care should be taken that they will not
block the builders' present or future needs.
HowAccess ible, and How Private Should the Sit& Be?
A building can only be easy to build and easy to use if the site
is accessible; that is, if it is conveniently close to other people
and places in the community and if it can be approached easily.
At the same time, a building can only be comfortable for those who
use it if the site provides enough privacy to satisfy their needs.
Privacy can also be important for health: for example, dirt, dust,
and smells can cause serious problems if a building is too close
to a heavily travelled road.
Because the need foraacessibility often conflicts with the need
for privacy, planners often have to compromise between them.
17
Access for Construction. Unless the materials for
construction are available on the site itself, some or all
of them will have to be brought to the site in large amounts.
Generally, this means the site should be near a road, or in
an area where a road to the site can be built. -In addition,
there must be space on the site to store materials during
construction.
Access for Use. To serve its purpose well a building must
be easy for people and supplies to get to. For different
kinds of buildings different considerations should be kept
in mind. For example:
SchooZs should be
- within reasorlable travel distance (by foot and/
or vehicle);
- close to clean water;
- close to fuel supplies in cold climates;
CZinics should be
- centrally located so that the community can reach
them easily;
- close to clean water and fuel supplies;
- next to a roadway suitable for vehicles;
Homes
should be
- close to clean water for cooking and washing;
- close to neighbors;
- close to fuel supplies;
- close to the family's fields or other places where
the family earns income;
- close to markets;
- close to community facilities.
Privacy, Comfort, Health, and Safety. All building sites
should be:
- away from rivers and streams heavily infested with
mosquitoes, or other sources of disease;
- away from forest, bush, or jungle (all these cut off
breezes, are dangerous in case of fire, and provide
homes for snakes, rats, ants, and other pests):
- away from major roads and other sources of noise,
dust, dirt, distraction, smells (this is especially
important for schools and clinics);
- away from flood-prone areas;
- away from fault lines in earthquake areas
(see section on earthquake areas, page 195.
18
What Kind of Soil Should the Site Be On?
Possibly the most important consideration in choosing any site is
that the soil must be able to support any building(s) erected
on it. Almost any ground can be built on (or over), but the nature
of the site chosen will affect the simplicity or complexity of
the foundation, the cost of construction in labor and money, and
the durability of the building.
. Rocky soiZprovides the strongest s-upport for a building,
usually much more than is necessary for a l-story building.
But while it is extremely stable, it can be very hard to
excavate.
l
Hard-packed
cZayis generally the best soil for l-story buildings:
strong, but easy to work with.
l
Sand a=pd
gravezare usually acceptable soils for l-story
construction. They can support about half as much weight
as clay, but they are subject to shifting
or
slipping,
especially if the site is-not on level
ground.
a
Soft b2ack sod2, drained ma.rshZand, and %ade" earth CfZ22 thut has been
co22ected
and
packed)
are satisfactory soils for construction.
However, buildings constructed on these soils should be
built on concrete foundations, or on raised platforms.
In addition, buildings on these soft soils should be made
with the lightest suitable rn;rfar;-l- available.
-..v --a. a.ULJ
Black topsoil contains decayed organic matter that makes
it soft, especially when moist. In areas where such soil
goes more than 30-45 ems. deep, it must be removed before
construction can begin. Otherwise it will almost certainly
shift under the foundation and lead to wall cracks or collapse
of the building.
Each type of soil has very definite limits to the weight it will
support. Generally speaking, l-story buildings will be well
within those limits except in the case of buildings with rock
walls on the weaker soils.
When a tentative site has been selected, it's a good idea to
double check that the soil at .2he site will support the planned
building safely. Quite often this can be done simply by looking
at similar nearby buildings
(2
or more years old) on the
same kind of soil. If they
show signs of uneven settling
such as cracks in the walls or
foundations, the side of the
new building may have to be
dug out and filled with firmer
soil, or another site may have
to be selected.
19
In cases where there are no similar buildings nearby, or no
similar soils, an estimate of the planned building's weight
per square meter should be made and compared with the weight-
bearing capacity of the site. Detailed directions for calculating
the weight of a building, plus a guide to the weight-bearing
capacity of various soils will be found in Appendix 1.
Almost as important as the type of soil at the site is the
uniformity
of the soil. If the ground at the site contains a
mixture of different soils,it must be dug out and filled in until
it is uniform in order to provide a stable support for any building.
If the ground at the site cannot be made uniform, or if the
weight of the planned building will be close to the weight-bearing
capacity of the site, it may be necessary to use reinforced
concrete in the foundation.
How We13 is the Site Drained?
In addition to the weight the site can support, builders need
to consider how well the land is drained. Water seepage can
destroy even the strongest foundation if it is not controlled or
planned for. Wet or damp floors can make a building uncomfortable
and unhealthful.
Whenever possible,
mmshZand
or any ground that lies underwater for
extended periods of time should be avoided for construction
purposes. In some areas, people have developed methods for con-
struction on stilts because they have no access to dry land, or
because they depend on access to the water for economic support.
Buildings in these areas should be made of light materials and
should be replaced often.
LOU-lying 2and,
and land that
may be exposed to short-term
flooding is also less than
desirable for construction
purposes. When there is no
choice, however, this kind of
land can sometimes be
improved by digging a trench
about 25 ems. wide and lo-15
ems. deep around those sides
of the building site that
won't drain. These trenches
should lead far enough from
the planned position of
the building to keep water
from rising to the foun-
dation depth.
247-801 0 - 17 - 3
20
If the dark topsoil in low-lying areas is more than 30-45 ems.
deep I every effort to find a different site should IX made, since
removing this topsoil for a firm foundation will be expensive and
can make effective drainage much more difficult.
High, dry groundis usually the best for building sites since it is
not subject to the ill-effects of water seepage. However, ground
can be too high. Planners need to avoid or guard against these
dangers:
*if the ground is also hilly, the excavation needed to produce
a level area for the foundation may be too difficult or
expensive;
*if there are heavy rainfalls, rapid drainage may cause
erosion, ground slippage, or landslides that can cause a
building to collapse or can bury it; in most cases, a re-
taining wall and carefully planted trees can solve these
problems, but both alternatives can be expensive;
*if high ground is exposed to high winds or storms, the
building may be in danger of collapse, olr it may lose its
roof.
The ideal site for any building is on dry soil safe from flooding
,and sheltered against gro*und slippage, strong winds, and storms,
4
How Should the Building Be placed On Its Site?
After selecting a site, the builder needs to decide where on the
site the building or buildings planned will be. The position that
is chosen should ideally:
l be far enough back from the site boundaries for privacy
and comfort
cleave room for future additions
*leave sufficient room for storage of construction materials
l allow the windows and outside doors to face as close to
north and south as prevailing winds will allow (see the
section on windows and doors, page 52)
*be as level as possible
ebe as dry and strong as possible
abe away from forest, brush, or jungle area on the site
@conform to all local legal regulations.
21
Summary of Factors Affecting Site Selection
The most important factors community groups and families should
consider in choosing a site for their building are:
gwhether the soil will support the weight of
the building;
*whether the site is drained well-enough to
prevent water damage:
@whether the site is large enough to accommodate
their immediate and future needs;
@whether the site is easily accessible for
construction and use of the building:
@whether the site is comfortable, safe, and
healthful.
In most cases, builders have to compromise between these concerns.
Choosing the best site among several less-than-ideal possibilities
is often difficult and complex. It is always best to get
experienced advice, whenever there is any doubt. Contractors,
engineers, or architects in the area can help make the options
clear, especially in terms of cost and labor.
P 4
O?W F&zZ
Gaxtim.
In many areas, local regula-
tions will influence what can be built;-where
it can be built, and how it can be built.
Building and zoning codes, permits, licenses,
and accepted practices vary widely from
country to country and locality to locality.
To avoid wasted or illegal effort, the field
worker should help family or community mem-
bers learn their restrictions and obligations
during the basic planning and design process.
This should always be done
before
settling on a
definite site for construction.
24
Don't forget to plan for latrines and a water supply on the
school grounds (see section on latrines for special rules that
apply to the location and number of latrines).
If needed or desired, thought should be given to space for
a school garden, lodging for teachers, and sports.
Here is one possible site plan including these features:
LATRINES t
i
---
RECREATION
Ii
h
s
s
u
VI
.-
n
5 FU
E
C
TEACHERS ’
BEDROOMS
1 I
!
TURE ADDI’
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L A
--
.
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.
!
I
TIDN i
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i
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WELL
i
r -B-w-- eT”a
i
I
COMiOST .
-e
I
1
i
I
!
GARDEN
I
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L I V’ESTOCK
!
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i
Health Clinks
25
Health clinics usually require more advance planning than schools
to fill a community's needs well, because separate rooms are
needed for the reception and treatment of patients, care of
patients who must sleep in the clinic, and space for office and
supplies. In addition, latrines should be included in the plans
for any clinic (see separate section on latrines for detailed
planning).
This is a floor plan for a
small
health station, with
3 rooms and 2 inside walls,
measuring
7
X 5 meters. Ii
I
*m
3 m.
OFFICE/
SUPPLIES
PAT I ENT
BEDRSUM
LATRINE
4
m.
RECEPTION/
, TREATMENT
A more complete clinic might be twice the size, 7 X 10 meters.
To reduce noise that
may
disturb in-patients, and to reduce the
possibility of infection, patient rooms should be as far as
possible from treatment rooms.
Ii
3
I
i
I
m
RECEPTION TREATMENT
PATIENT BEDROOM: OFF I CE/SUPPL’I ES. LATRINE
26
LATR I kr
A desirable addition to one of
these clinics would be a midwife
station in a separate structure
on the same site.
Midwife stations permit special
care for mothers and babies
during and after delivery,
without exposing them to infection
from clinic patients.
Here is a possible plan for a
midwife station.
TREATMENT
This is a SITEplan for a complete health clinic.
----
i
LATR I NES
i
i
27
In normal times, housing projects are more difficult to organize
than community projects such as schools and health clinics. But
after a disaster, such as an earthquake or flood, many people
are in urgent need of new homes ---at a time when they may be least
able to afford construction or to think carefully about their.new
home's design without help. As a result, many agencies providing
disaster relief have tried to design and build new homes for people
---only to find that the new homes stand empty‘because people don't
like them. This problem can be avoided if field workers use the
ideas suggested in this section to help families plan their own
homes.
As with schools and clinics,
the smaller a house, the less
it will usually cost to build.
Here are some guidelines to
help a family decide what
their
minimum
needs are:
l
The plans for a house
should clearly shah?
where each of the
family's basic activities
will take place. Even
the smallest home must
have adequate space,
either inside or out-
side, for the family to
sleep, cook, eat, and
move around in comfort.
BATH I NG
I
EAT I NG
l
In addition, the family should consider including space in
its plans for a latrine and a shower. Latrines are especially
important for every family's health. They can be designed
as part of the main house itself. But there are several
advantages to building latrines as separate structures on
the same plot of land. For example, an outdoor latrine
can be moved easily when it fills up.
l
Other activities a
t:,A.ly
may wish to plan space for include
laundry, prayer, and private space.
. When cost is a critical problem, a family can save money by
using rooms to serve more than one purpose: for example,
a single room can provide living and eating quarters by day,
and sleeping space by night.
28
The following questionnaire can be used to help a family determine
what kind of space they need and how many rooms they need to
build.
01 ’ I ’ ’
A. SLEEPING SPACE
1. How many people will sleep in your
house?
2. Which people will share a bedroom with
each other? (Write their names in the
blanks for each roomi
Room #l Room #2 Room #3
.-
3. In the circle to the left, write the
number of rooms needed for sleeping area.
B. DINING SPACE
1. How many people will eat at your house?
2. Will they eat inside or outside? Will the
eating space be attached or unattached to
the house? (Check the correct boxes)
3. Can one of the bedrooms also be used for
dining space? (If yes, leave the circle to
the left blank; if no, write in 1.)
C. LIVING/SOCIAL SPACE
1. Do you need space inside and/or outside
for family members to spend time
together or for visitors?
2. If so, can this living space be the same
as your dining area? If yes, leave the
box blank; if no, write the number of
inside/outside rooms needed for living/
social spaces in the circle. Check if
spaces will be attached or unattached.)
D. COOKING SPACE
1. Do you plan to cook inside or outside
your house?
2. Do you want the cooking space attached to
the dining area or unattached? (Write the
number of cooking spaces needed in the
circle and check the correct boxes.)
b
O”T”
O’“-”
E. BATHjPERSONAL WASHING SPACE
1. How many rooms for personal washing do
you need?
2. Will this space be inside or outside the
house? Attached to the house or not?
F. LAUNDRY SPACE
1. Do you need space in the house for doing
laundry?
2. If so, will the laundry space be inside
or outside the house? Will it be attached?
3. Can the laundry space be in the same
area as the bath? (If yes, write "0" in
the circle; if no, write "1")
I 1
G. PORCH/VERANDAH
1. Do you need a porch outside.your
house? If yes, write "1" in the circle!
If no, leave the circle blank.)
H. STORAGE SPACE
1. Do you need separate room(s) for storage?
Will they be inside/outside,attached/
unattached? Write the number of rooms
-needed in the circle and check the correct
boxes.
I. OTHER SPACES NEEDED
1. Do you need separate rooms for other
activities besides those listed above?
For example, do you need separate space
for prayer, family meetings, or other
needs? If so, write the number of rooms
needed and the purpose for each one:
-
Check over your answers to these questions. The information
you've listed should help you decide exactly how many and what
kind of rooms/spaces you need to plan.
WHAT SIZE WILL EACH ROOM BE?
Ta be useful and comfortable, a room must be large enough and
properly shaped for its function. For example, a bedroom must
be long enough for a person to lie down in and wide enough
so he or she can get out of bed and in and out of the room
easily. A latrine, on the other hand,only needs to be large
enough for a person to sit or squat (unless people also plan
to dress or wash in the same area).
The best way to make sure that a room will be large enough is
to decide how large it would have to be for the largest adult
likely to use or visit the home. Then the room will be com-
fortable for everyone.
[Note: Often the proper size and shape of a room is determined
more by traditional requirements and social patterns than by
physical comfort. Field workers must be sensitive to the
community's needs and priorities and should explore them
thoroughly with the family.]
Here are some guides for a "human" measuing unit:
- Most adults will be less than 2 meters tall;
- An adult usually needs 2/3 meter from side to side and
from front to back in order to move around; and about
1 meter, or nearly half his/her height,to sit down.
2/3
m.
l+=-
1 m.
31
USING MEASURING UNITS TO HELP THE FAMILY PLAN ITS OWN ROOM SIZES
A family's interest and confidence in a building project will be
much gre,ater if they are able to envision and plan their home's
rooms themselves. A first and very important way the field
worker can help them do this is to visit other homes in their
community with them and question them carefully about their
reactions. Some questions a family might want to ask include:
. Do we want our rooms to be larger or smaller than these?
. Would we like them to be the same or a different shape?
a How do we feel about rooms with more than one purpose
(for example, sleeping, dining, and living)?
0 Are the rooms we have seen easy to move around in, or
difficult?
.
l
Is working in the kitchen or laundry space easy, or does
it take a lot of walking back and forth?
l
Do family members get in each other's way when moving from
room to room? Where and why?
Once the family is familiar with a number of different possible
designs, they will need to put the actual size and arrangement of
rooms in their new home on paper.
An easy way to help them get started is to give the family pieces
of paper representing the "human" measuring unit. Using 12 cm. for
1 adult length is the most convenient.scale since. l/2 adult is an
,even 6 cm. and l/3 adult is 4 cm, The family
will need pieces for:
*
the length and width of an adult
standing or lying down;
*
the length and width of an adult
sitting;
*
the space an adult needs from side
to side in order to walk or work
*
any furniture they have or special space needs
(for example, in countries with cold climates,
space may be needed for chamberpots in the
bedrooms so people don't have to go out at
night).
Remember that the pieces must be proportional to one another so
that they can be used to get an accurate picture of the space
needed.
NOTE: Extra copies of the planning pieces for use with a
community group-are provided in Appendix 8.
A family can design its own
rooms by gathering pieces it
needs for any room and then
arranging them into a square
rectangle, or circle.
For example,
a family planning
a bedroom for a couple and
one child would need:
,, 2 pieces of an adult
length and width for
the couple's sleeping area:
l
1 piece S-length x $=-length
for the child's sleeping
area;
. 1 piece f-length x S-length
for an adult to sit;
. 1 strip the width of an
adult for clothing or
storage:
.
2
strips the width of an
adult for each parent to
walk around their bed(s),
and to walk to the baby's
bed;
0 extra pieces for large
furniture or other
needs.
33
Once the pieces are gathered, the family should try to put them
together so they form a room-shape. There are many combinations
possible for any room, so people should be encouraged to
experiment with AF. many arrangements as possible.
ALTERNAT IVES
When all the pieces have been
placed together, a line should
be drawn around them. -This
line represents the complete
room‘113
If the shape of the room is
irregular, the field worker
should help the family
make adjustments until it
is a simple shape.
FINAL CHOICE
Space can be added to complete a square, rectangle, or circle,
Some
of the space in walking areas
up to l/3. can be carefully reduced by
.
To find out what the dimensions
of the final room should be,
first calculate the number of
adult lengths along the sides
of the room.
Then the family, or the field
worker, if necessary, should
multiply the number of adult
lengths by
2
meters.
The answer will equal the actual
dimension of the wall in meters.
f ADULT 3 ADULT + ADULT
EXAMPLE: Caihduttin of Dimensions
of
Rectangub Room Above
width:
f adult length
3 adult length
& adult lerkjth
14 adult ?engths x 2 meters = 3m
Len&+
1
adult length
2/3 adult length
l/3 adult length
2 adult lengths x 2 meters = 4m
Room DGnensions: 3 meters x 4 meters
Here are some additional measures that may be useful in deciding
what pieces the family must use in planning kitchens (or outdoor
cooking areas), and dining areas:
l
Work space in kitchens, especially counter space should
be about l/2 adult wide. Anything wider will be hard
to reach across;
l
Space for fuel in kitchens should be about l/2 adult long
by l/2 adult wide:
. Dining space for each person (that is, space for the
person to sit and space in front of him or her to eat)
should be about l/2 adult wide and 3/4 adult long.
COMBINATION
KITCHEN-DINING
l/4
ADULT
%xg
PLANNING A BEDROOM FOR 1 PERSON
TOP. VIEW
I
11 ADULT LENGTHS I
36 36
Let's look at how the "human measuring unit" can be used to plan Let's look at how the "human measuring unit" can be used to plan
several rooms. several rooms. These suggested plans may be useful if a famJ.ly These suggested plans may be useful if a famJ.ly
has problems picturing what they can do with the "pieces" for a has problems picturing what they can do with the "pieces" for a
room. room.
( Note: ( Note:
the field worker may want to adapt these illustrations the field worker may want to adapt these illustrations
if the furniture shown here is not relevant to the local area) if the furniture shown here is not relevant to the local area)
SIDE VIEW
This is how the room might look.
37
BEDROOM FOR TWO ADULTS
OR A COUPLE
OR PARENTS AND CHILD
I 1 &ADULT LENGTHS I
38
DINING/FAMILY ROOM
2 ADULT LENGTHS
39
Kitchens may be inside or outside:
but in either case, they must be
big enough to store all utensils
and food away from animals, and to
provide working space; at the
same
time, they should be small
enough so that everything can be
reached easily without many
trips between supplies.
Shelves and cupboards save floor
space. In places where the
kitchen is primarily for storage
and most of the cooking is done
outside, the kitchen can be
smaller.
_&-ADULT
1 ADULT SITTING
Latrines can be
small:
1
m. X 1
m.
However, if
they are built longer, they
will be easier to clean and
to move around in. (See the
separate section on latrines,
page188 for more details).
Door opens in for privacy
Bathrooms require room to shower or
to dry oneself, and to get
dressed.
1 ADULT LENGTH
A verandah, or porch, is really
a room with 2 or 3 sides open
to the air. It should be big
enough to be comfortable for
social gatherings, family,
prayers, or other meetings;
this means at least one adult
wide and one adult long (longer
for large groups), so that there
will be room to sit or lie down,
and to walk around anyone using
the room.
HELPING THE FAMILY DRAW ITS OWN FLOOR PLAN
When the number and size of rooms needed have been determined,
the next step is to decide how they should be put together to
form the house.
The easiest way to do this is to draw a picture of how the
rooms would look from above if the roof were removed. Since it
shows how the floor-space in the home will be divided among the
rooms, such a picture is called the floor plan.
One thing to keep in mind when designing a floor plan is to keep
the shape of the building as compact and simple as possible. Odd
shapes and sharp angles are more difficult and more expensive
to build than either rectangles and squares. Curves are also
expensive except when bamboo, or similar materials are used.
As in planning room size, the family's interest and confidence in
a building project will be greater if family members participate
in the drawing of their own floor plan.
The field worker can help them
draw the plan by giving them
scale model pieces of paper
or cardboard representing
the rooms they have planned
and helping them arrange the
pieces in several different
"floor plans".
Each possible floor plan
should be discussed at length
in order to determine how
well it will fit the needs
of the family.
41
When a final decision has been reached, the arrangement of the
room-pieces can be copied on a single sheet of paper. This
paper then becomes the floor plan.
42
DRAWING THE FLOOR PLAN OF A HOUSE
Here are some step-by-step examples of how the floor plan for a
small family's house might be developed.
Sample Plan #l: House for a couple with no more than 1 child
A good way to start a floor plan,
is to place the piece for the
main bedroom (the room where the
heads of the family will sleep)
in the center of a sheet of
paper.
For a couple with no children,
this might be the bedroom
suggested on page 37. This
size has the advantage that a
first child could be easily
accommodated without cramping.
To this bedroom might be added
a kitchen and a living/dining
area (both kitchen and dining
area are shown indoors here:
if either or both will be
outdoors, the space required mciy
be very different).
At this point doors have not
been shown in the
illustration.
Or, the
same
space can be used as
a porch:
43
The home could be built on tnls
plan. But any of several changes
or additions to complete the
square are possible. If grand-
parents or aunts and uncles
are part of the family, they
may require the main bedroom;
in which case, a second bedroom
would be needed.
In a nuclear family, a shower
can be added, along with
some
storage or laundry space to
complete the square:
Storage/Laundry
Finally,
a
latrine should be
a
latrine should be
planned near the house, planned near the house,
preferably where it will be preferably where it will be
sheltered from public view, sheltered from public view,
Storage/Laundry
Sample Plan Sample Plan
#2: #2:
Holuse for a couple with no more than 1 child. Holuse for a couple with no more than 1 child.
A less expensive alternative for A less expensive alternative for
the same couple would be to build the same couple would be to build
a single bed/living-dining room a single bed/living-dining room
using a screen to separate the using a screen to separate the
two areas instead of a wall: two areas instead of a wall:
III
Latrin
45
Sample Plan #3: House for a
Small
Extended Family or A Couple
With 2-a Children,
To design the floor plan for a
slightly larger family, all the
planner needs to do is add a new
bedroom to the smaller homes
shown in Plans#l and C2.
For example, the verandah in
Plan #l could easily be remodeled
as a bedroom for two children or
an aunt and uncle:
.
Plan #l could also accommodate a new room either next to the
dining room, the first bedroom, or the shower:
Storage/Laundry
Bed room
Kitchen
Bed room
Dining
In Plan
#2,
the original bedroom
can be converted into a room for
two children or grandparents, and
a second, smaller room for the
parents could be added on the
other side of the kitchen area.
Bath I Kitchen
Dining/Bedroom Bed room
Sample Plan
84:
House for a family of
4
or 5,
Ijere.'s another plan for a family of 4 or 5 that could be added
to if the family continued to grow:
Fut
Future
-o-----w
IT--------
II
II
II
II
‘I!
ure Addition
1
I.
II
II
II
II
II
iition
Bed room
Bath
Ki tchen
Dining
PO rch
II
! !
Future Addition
ii
II
ii
.
II
m----I.---*
m-------- 11
47
.Some Points to Remember About Floor Plans.
l
l
The kitchen and dining areas should always be
next to each other so that food can be carried
easily from one to the other. If dining will
be outside, the kitchen should have an outside
door.
In countries where privacy is important,
each bedroom should be planned with separate
access to baths and/or indoor latrines, so
people won't have to pass through someone
else's bedroom.
In many countries, standard floor plans
for various size homes are available from
the government or local architects and
engineers. But check to be sure that these
plans are appropriate for lower income family
needs!
A good way to find out what makes a good
floor plan is to explore homes in the local
area and copy or adapt successful ideas.
Such a survey can be especially helpful
in planning so that family members will
not get in each other's way when moving about
the house.
48
Doors, Windows, and Ceilings In All Buildings
WHERE WILL INSIDE DOORS HE PLACED?
No floor plan is complete until it
shows where the inside doors
between rooms will be placed and
how people will move from room
to room. (For outside doors,
see the guidelines for windows
and special notes on page 65.
Inside doors should be designed
to:
l
provide easy movement
between rooms:
l
provide privacy (if desired).
Easy Movement depends
primarily
on the siae of the doors. They
should be one adult high, or
2 meters,
and at least 75 to 100
cm. wide for all rooms except
bathrooms, which can have narrower
doors,
60 to 75 cm.
One other factor that can affect
ease of movement is how-close doors
are to other parts of the house.
Doors should be placed so that
they don't interfere with other
doors, open windows, or major
pieces of furniture (such
as
beds).
Privacy depends on how much of a
room can be seen through the door-
way. There is no problem when the
door is closed. However, it i.p
often desirable to leave the
door open for air circulation.
Privacy can still be maintained
if the door is placed properly
and opens in the right direction.
The chart on the following page
shows the right and wrong ways
to place doors in a room.
rF5-l
Ii
N a
49
Door Placement.
Doors should be placed--and hinged-- so that as little as possible
of the inside of the room is‘seen when the door is open.
INCORRECT: No privacy because passersby can
see into room.
CORRECT: View is blocked
by door, al though
it is left open
for circulation.
rn
50
Doors are shown in floor plans by drawing a line representing
the door in the open position.
l
Here are some examples of how doors might be shown in the floor
plans we've already seen:
HOW HIGH WILL THE CEILING BE?
Ceilings must be high enough so
that people can stand up
comfortably. The best rule to
follow is to keep the ceiling
about l/3 meter above the doors,
or about 2 l/3 meters high.
If ceiling lights or fans are
planned, then add about 2/3
more meters to make the ceiling
at least 3 meters high.
AVERAGE
In tropical areas, higher ceilings
are significantly more comfortable
if they are ventilated to allow
heat to escape. Buildings with
because heat collects in the
space above doors and windows,
making it difficult to keep the
rooms cool.
Avoid high ceilings in cold
weather areas: they make rooms
harder to heat because the warm
air from people, fireplaces,
or heaters rises to the ceiling
where it cools off before it
can warm up the living area.
51
HEIGHT IF FAN
OR LIGHTS ARE TO
BE IN BUILDING
unventilated high ceilings
tend to be very uncomfortable
HOT AIR COLLECTS AND IS TRAPPED NEAR CEILING
..-.
* .- . ..L l . ,..-,
.‘ii ;.r.;~i..~:oS.i : c;W..“; /‘~.I~~
.* . ..- \. ;.. . . .:- *.~~..*y,..“‘.., .-: . . . . . . . . ,
. ..:
:: -
.$ ;“‘.. : f i;> ) : ,.. :
. . i :
i:Zj~‘3,~~‘~~“:
1 i -’ ; . . ‘-: . . . . :‘:.y
! :<.., i..g : y-y:,< ., .!-
.,.‘..... ;.. ::.*..- . ..* ; :
~ i . ..* . . . . .._...*... ::..:**.. &I i
. ..i j
.’ -“..~
-..** :‘pj , .- ,. ” ...“‘-.. :‘:::’ :~‘:.:.i...”
. . . . ..... ! :-.. .., ; ; ; ;
* : : : ui‘y?
.s .“.,I . ; ; ! : :
i ! i
it;s::
p; ‘w..<y. ..’
:::.I
:::::i
i i : i : :
i : : :
ii:::;
:!iii:
l-l:
ii.:::
i i i i ;
i i
I I
COOL AIR REMAINS BELOW
247-801 0 - 77 - 5
52
WHERE WILL WINDOWS AND OUTSIDE DOORS BE PLACED?
HOW WILL THEY BE DESIGNED, AND WHAT SIZE WILL THEY BE?
Most windows do the following things, in varying degrees:
- they aid the circulation of air in the building;
- they provide light (and warmth, in the daytime);
- 'hey provide a view of the outside (and they also
allow outsiders to see in).
At the same time, windows can do the following things, or fail
to do them:
- protect from too much wind, rain, heat, and glare;
- help keep the house cool;
- ventilate enough to control mildew and molds.
The best size, design, and placement of windows for any building
depends on how much light, heat, and wind is desired inside.
So the most important consideration in planning windows is the
climate. Generally, the best way to design windows is to survey
the windows in nearby buildings and use ideas that have worked
well in local conditions.
But there are some general guidelines the field worker can
follow in advising a community group or family. Here are two
typical climates and what you would want to achieve in each:
Climate
Tropical
Windows shouid be designed to:
- avoid heat from the sun;
- protect inside of the building from rain
and insects;
- take advantage of any breeze day or night.
Desert - avoid heat fromlthe SUni
- protect inside of the building from dust;
- protect inside of the building from wind,
especially at night.
53
D
WINDOWS IN A TROPICAL CLIMATE
Avoid Heat from the Sun.
Two things can be done to avoid
too much heat from the sun:
* windows can be placed so they
face away from the mid-morning
and mid-afternoon sun:
- near the equator, windows
facing north or south will
absorb the least heat;
NORTH
SOUTH
--m--m
-a-----
--- -mm
Strongest
Sun1 ight
NEAR EQUATOR
north of the equator,
windows facing northeast
and southwest will absorb
the least heat;
- south of the equator,
windows facing the northwes
and southeast will absorb
the least heat.
SOUTH OF EQUATOR
* Windows can be shaded:
- with full or partial shades
built around the outside of
the building:
PARTIALLY SHADED WINDOWS
- with the overhang of a roof;
(the overhang should be
half the height of the wall)
- by a porch;
a porch serves as an
open air, shaded area
for rest, dining, and
social gathering while
at the same time pro-
tecting the windows and
building from the sun.
SUN1
SlidLIGHT
- by designing them as
self-shading walls; thick
bY a shaded inner courtyard;
- or
by
trees or other plan
PROTECTING THE INSIDE OF THE BUILDING FROM RAIN AND INSECTS
The best protections against bad weather and insects are outdoor
shutters and screens. Shutters and screens can both help protect
the building from animals and thieves
A variety of shutter designs can be used alone or in combination.
The best combination in the tropics is usually a mesh screen
(for insects) with a glass , wood, or well-made bamboo or reed
shutter (for rain). The illustrations on this page and the next
show several shutter and screen designs, along with their uses.
Mesh Screen
l
lets in some light, heat, cold and
dust
l
keeps out insects, some light and
some breeze -
Glass
l
lets in light and heat
l
when closed, keeps out cold, wind,
rain, dust, and insects
Fixed Screen
l
lets in some light, fresh air, heat,
breeze, and insects
l
keegs out some light, glare, sun
D
B
57
Reed Screen
o woven pattern slides over at night
. lets in some light, heat, cold, and
insects
Solid Wood
l
lets in heat, light
l
keeps out some light, cold, wind,
rain, and when closed, dust and
insects
Louvered
l
lets in some of everything
. when closed, keeps out wind, rain,
dust, and insects
D
Double-door Shutter
l
when open lets in everything
l
when closed, keeps out everything
3
“‘>I
1: ,,
58
TAKE ADVANTAGE OF ANY BREEZE
For noticeable circulation, there
must be windows on more than one
wall.
The building should be placed so
that the windows face intc
light breezes, but away from
harsh winds, and also away from
the mid-morning/mid-afternoon
sun.
INCORRECT: Breeze can’t pass through bu
CORRECT: Breeze passes freely through
59
Here are six situations showing how buildings in the tropics should
be placed depending on the direction of prevailing winds and the
position relative to the equator.
I.I
. ..p ..’
/; y..: *._. *-
..“.~J
-.. . ...+*
a ..:*..I;
,. . .
,*.:,
_ . ::-.:..
.:.+ . .
. .
.-i-.1.1.1 :: . :‘: - .
-. ..:-1.:‘.
-“--‘\
i I
i.
tIzl 1 ,
* %
. . ‘..
‘..>:: -. . .
-..;. . -*,
.,*-.
-3
.:W:‘:..
. . . ...* y:‘,
, .-.
-, ..a....*
--.-: _
.<-:‘,
*r =.*
.m..-.-
NORTH OF EQUATOR
Northeast or Southwest Winds.
Windows face North and South to
catch breeze and avoid sun as much
as possible.
All Other Winds.
Windows face Northwest and Southeast
to avoid sun and catch breeze as
much as possible
NEAR EQUATOR
Due East or WestWinds.
Windows face North and South as
much as possible to avoid sun, but
they catch breezes.
All Other Winds.
Windows face North and South to
avoid suni and catch breeze.
SOUTH OF EQUATOR
Northwest or Southeast Winds.
Windows face North and South to
catch breeze and avoid sun as much
as possible
All Other Winds.
Windows face Northeast and Southwest
to avoid sun and catch breeze as
much as possible.
Another way to increase
circulation is to use as many
windows as possible. But bear
in mind that:
- building windows can be costly
in labor as well as materials;
- walls facing mid-morning or
afternoon sun should not
have more than one window
per room (so as to reduce
heat from the sun).
Th,e size of windows also affects circulation
because larger windows .allow more air in and
out.
Again, some cautions:
- the larger the window, the more expensive
it will be to build:
- since there most likely will be times when
the windows must be closed with shutters,
they should not be much bigger than about
1 X 1 l/3 meters. Anything larger may put
too much of a strain on the hinges and
make the windows difficult to open and
close;
- large windows offer less protection against
thieves or animals.
b
b
61
One final consideration in getting
the most circulation possible is
the height of the windows. Most
windows in tropical areas should
cover the upper half of the wall
so that any breeze will be felt
around the head and shoulders.
A few additional windows covering
the lower half of the wall,
especially in sleeping areas, will
further increase circulation.
Construction will be much simpler
later if the tops of windows are
kept level with the top of the
door (about 2 meters).
To sum up, a good plan for a building in a tropical climate
would have:
- windows facing away from the mid-morning and mid-afternoon
sun;
- shades, overhanging roofs, or a verandah;
- several windows, placed opposite each other so wind can
flow through the building (but no more than one on walls
facing mid-morning and mid-afternoon sun);
- large windows covering as much of the upper half of the
walls as possible plus a few windows in the lower half
of the walls, especially in sleeping areas; (make sure
they are not too large or heavy to open and close easily)
- screens tokeep out insects, and shutters that can be
closed to keep out rain, wind, dust, animals, and thieves.
62
WINDOWS IN A DESERT-LIKE CLIMATE
Avoid Heat from the Sun.
The same rules apply to windows in desert-like areas as annlv
to windows in tropical areas.
Windows should be placed to avoid direct sun in the mid-morning
and mid-afternoon.
Buildings in desert-like areas are often built around open court-
yards shaded
by
trees and the walls of the building itself,
so that windows open onto cooler air (the same idea is used
in tropical areas, too, but less often).
Buildings can also.be placed close
together so that each shades the
walls and windows of the building
next to it. This may block some
breezes, but since winds in the
desert tend to be hot and
uncomfortable, it isn't so
important to keep buildings open
to them.
BUILDINGS SHADE EACH OTHER
Windows in desert areas can also
be protected from the sun's heat
by designing them as openings
in thick, self-shading walls.
sutd
CHINES 0~
LITTLE HEAT &
\
SIDE\/IEW’
OUTS1 DE WALL BUT
LIGHT ENTER BUILDING
Protect Windows from Uncomfortable Winds.
since so= ~nc-l+ winds =s-- hot
--w-a w -*-
and uncomfortable, people want
to be protected from them
rather than exposed to them.
On the other hand, a building
with no circulation at all would
be uncomfortable and unhealthful.
The best way to protect against
uncomfortable wind without cutting
circulation entirely is to plan
small windows opposite each
other.
.SMALL WINDOWS
;: ,
i I / : , : I
:i : ii .,t
i a' ,: .-
:
Protect Windows from Dust and Glare --
In many areas, the ground tends to be dusty. In addition,
because it is often bare and light in color, it reflects sunlight
in strang glare that can be very uncomfortable.
Both dust and glare can be effectively guarded against by
placing smqll windows high up from the floor. This prevents
most of the dust picked up by winds from getting in, and
blocks all the glare.
D
b
65
To sum up again, a good plhn for a building in a desert-like
climate would have:
- windows and doors facing away from mid-morning and mid-
afternoon sun;
- small, deep-set windows to protect against hot winds and
direct light;
- windows placed high to protect against glare and dust.
EXTERIOR DOORS
Like windows,
mind: exterior doors should be designed with climate in
a they should be placed to avoid heat from the sun;
l
they should be shaded from rain if they open outward, or they
should be designed to open inward (otherwise weather will.
spoil the wood or bamboo and cause the door to twist, warp,
or rot):
I generally it is worth the expense to shade doors so they
can be opened outward since this is safer in emergencies
such as fire or earthquake, and increases the amount of
useful space in the building;
a in earthquake areas, outside doors should be placed close
to the center of the wall's length (see the separate
section on earthquakes (page 196).
--
CONSTRUCTION MATERIALS
Q
Schools, clinics, and homes can be built out of an almost endless
number of materials.
The proper choice of materials depends on almost as many
considerations, including:
. the climate: some materials cannot withstand large rainfalls;
0
the part of the building (floors, walls, roof, etc.):
some parts need to be stronger than others;
9 the builder's budget: some materials are much more expensive
than others for original construction, maintenance and future
additions;
I the number of people working on the construction: some
materials require many more people than others;
. the amount of time available for construction: some
materials take months to prepare properly.
For any application, there are usually several materials to
.choose from that will be within the budget, time, and labor
limits of the builders. Whenever there is a choice, the most
important consideration is what materials (and equipment) are
available at or near the site. Local materials are almost
always less expensive, more acceptable to the people who will
use the building, and more familiar to those doing the construction.
4
This section is designed to review basic information about the
most common materials that small rural communities are likely
to find nearby. Detailed directions in the use of these materials
will be found in later sections covering the actual construction
process (pages 115-180).
But once builders know the major characteristics of the materials
discussed here, a brief survey of what is locally avaiiable
will usually be enough to decide what to use.
a
67
Rammed Earth (Mud, Pise) and Adobe Blocks
Rammed earth is a combination of sand, silt and clay that when
properly pressed and dried is suitable for walls in dry climates.
(wet climates, too, when protected with lime plaster.) If the
sand, silt, and clay are locally available, rammed earth and
adobe blocks are two of the least expensive materials to use.
Basically, the ingredients are mixed with water in this ratio
by volume:
l
50
to
80%
sand (the most important);
l
Up to
30%
clay;
. 15% silt (extremely fine-ground rock).
The amount of water needed varies considerably and must be
determined by making several tests. There should be enough to make
a mud that holds its shape but can still be molded,
@nce the ingredients are mixed
thoroughly, they are pounded
with a thin pole into a portable
mold (form) 2/3 to 1 meter high
until they are packed solid.
The mixture is then allowed to
cure (dry) thoroughly. When
one section is ready, the mold
is removed and used to' form the
next section
RAMME DE ARTH FORM W
CRETE/BLOCK FWN DAT I ON
Adobe bricks are individual solid blocks made from the same
mixture of ingredients as rammed earth.
A simple form - or mold - is used to shape the bricks, which
must be dry for at least a month before use. Because of the
drying time needed, adobe bricks can only be used where there
is a long season of hot dry weather.
ADOBE FORM
\I
Construction with either rammed earth or adobe is inexpensive
and highly labor intensive. This makes both materials
especially good in low-income communities that can contribute
volunteer labor.
Rammed earth and adobe should never be used underground for
foundations, since underground moisture will eventually weaken
them. Both materials are excellent for walls, however, and can
withstand rainfall if protected with lime plaster.
In earthquake areas, rammed earth and walls must be reinforced
with wood, wire, or bamboo.
Finally, rammed earth and adobe structures cannot support heavy
roof loads without strong wood or iron reinforcement. Light
roof materials, such as thatch or bamboo, are the best to use
with either rammed earth or adobe brick walls.
69
Wood
wood is one of the most versatile and durable construction
materials. It is easy to work with and can be used to build
almost any part of a structure.
countries, however, Due to deforestation of many
wood is too scarce and expensive for use by
most low-income communities as their main construction material.
Field workers in countries like Thailand or Malaysia where wood
is still plentiful may wish to consult one of the many excellent
books-describing wood frame construction listed in Appendix 7.
Over the long-term,projects to re-plant forest
replenishable source of wood for construction
desirable. But most communities now will only
wood as a secondary material for:
areas as a
(and fuel) are highly
be able to afford
. roofs;
. doors and door frames;
o shutters, windows, and window frames;
. porch railings and posts;
. wall reinforcements (especially in earthquake areas)
e forms for poured concrete, blocks, temporary frames and
braces, and scaffolding for roof construction.
The best timbers to use are generally those that are hard and have
some resistance to decay, rot, and termite attack, such as:
- Lignum vitae (West Indies)
- Honduran Mahogany
- West African Odum and Okan denya
- Asian rosewood and teak.
Some softer woods, such as Eucalyptus Pine, are also quite good.
When in doubt, a survey of nearby buildings may help to determine
which local timbers have proven successful.
‘d
Bamboo is an excellent material for almost any part of a building
except the foundation.
inexpensive. Where available it is usually very
Its light weight makes it very easy to work with--
generally easier than wood.
Bamboo must be used with care, however, because it cannot support
great loads or excessive dampness or rain.
water, Because it decays in
it cannot be used underground for a foundation.
Since construction with bamboo is very different from construction
with other materials,
beginning on page 181. it is covered in a separate section
70
Stone and Rock
Piles of stone and rock can be
used to make strong foundations
and walls, especially if used
with a cement-based mortar to hold
them firmly together.
Stone and rock have several
disadvantages, however:
l
if not locally abundant,
they are expensive to
obtain;
e walls made with rock or
stone have many uneven surfaces.
Filling in the large cavities
in order to made inside walls
smooth is time-consuming and
expensive;
o walls of rock/stone must
be thicker than cement block
walls if they are to be
equally strong;
l
building to precise measure-
ments is difficult or
impossible; builders planning
to use rock/stone should
plan slightly larger rooms
and construction sites to
ensure that the finished
building will be large enough.
Cement and Materials Made With Cement
Cement is an adhesive material that l'bondsV' or glues objects
such as rocks or grains of sand together so that they form a
strong permanent piece. A useful cement can be made locally
from finely-ground limestone. But commercial cement:; also
contain silica, alumunum, and iron oxide. These materials
ensure that the mixture will contain a variety of grain sizes
The more different grain sizes there are! the stronger the cement
will be.
71
Because of its bonding action, cement is used as an ingredient
in many construction materials including:
. mortars
l
concrete
- poured
- reinforced
. blocks
- concrete blocks
- sand-cement (sand-Crete) blocks
- stabilized earth blocks
Each of these materials is discussed below.
Generally, cement is used two ways:
a as an ingredient in mortars, (pastes used to bond bricks,
blocks, or stones,and to plaster walls);
. as an ingredient in concrete.
Mortars
Mortar is a general term for any
mixture of cement with
sand and either lime or clay.
The ingredients are mixed in
varying proportions with water
to form a paste that can be used:
- to bond bricks, blocks, or
rocks;
- as a wall finish (plaster,
stucco).
The tables in Appendix 5 give
recommended proportions for
different mortar uses.
Concrete
Concrete is a mixture of sand,
gravel, and water that is held
together and given strength by
cement.
The strongest concrete has
particles ranging from very fine
sand to gravel of 3.75zeters
Some
builders and manufacture
refer to the sand as fine
aggregate, and the gravel as
coarse aggregate.
across
rs
ENLARGED CROSS SECTION Of CONCRETE
72
Before concrete can be poured, wood forms must be carefully
built to hold it in the exact size and shape desired. When the
formwork is ready, plain wet concrete is mixed, poured in the
forms, and allowed to cure (dry) for a few days to a few weeks
(depending on the weather and type of construction).
Plain poureu concrete can be used to build:
a foundation footings (pads of concrete that distribute a
building's weight over a wide surface);
. blocks for foundations and walls;
. floors.
The proportions of cement, sand, and gravel vary according to
the planned use of the concrete. But these proportions are
always referred to in the same way by builders. For example,
a formula often used for foundations, 1:2&:3, means concrete
composed of 1 part cement, 22 parts sand, and 3 parts gravel.
A builder usingthis formula would need 24 wheelbarrows of
sand and 3 wheelbarrows of gravel for every wheelbarrow of
cement. In addition, he/she would need approximately
23 liters of water to be added to the mixture.
Reinforced Concrete
Reinforced concrete combines two
materials with opposite-
characteristics:
CONCRETE ALONE IS NOT STRONG ENOUGH
. plain, poured concrete: s
resists downward pressure
(compression), but will not
bend; it cracks instead;
. iron rods: will bend (they
have tension strength), but they
will buckle under compression.
Reinforced concrete is prepared and
handled as plain concrete is, except
that an iron rod, or a series of
rods,is fastened inside the
form before the concrete mixture
is poured in. (In some cases,
bamboo stalks can be used for
reinforcement in place of iron
rods.
See -page 188).
a
73
Reinforcing concrete either with iron
or bamboo is fairly easy and can
D
multiply the strength of the concrete
2 to 5 times in:
walls;
support walls
and ceilings;
un-supported sections of
such as overhangs or balconies.
Blocks
A variety of blocks can be made by combining cement with other
ingredients. All these blocks are useful for foundations and
walls and can be produced locally if the proper ingredients
are available. They can either be made by hand or with a simple
press. A press is generally more efficient and produces a
stronger, more tightly-packed block than can be made by hand.
Whether made by hand or press, the blocks can be solid or hollow,
depending on the mold chosen. Hollow blocks use considerably
less material, reduce weight, and improve insulation. They are
not as strong as solid blocks. But in sections of a building
where additional strength is required, the hollow parts can easily
be filled with poured concrete or other reinforcing materials.
TWO BASIC BLOCK-MAKING PROCEDURES
J/By Hand. #l Gather and Mix Ingredients
#2 Pour Mixture in a Mold
#3 Pack Mixture Tightly in Mold with
Shovel
#4 Add More Mixture and Pack Again
#5 Remove Mold
#6 Cure (Dry)
By Hand-press.
#l Gather and Mix Ingredients
#2 Pour Mixture in a Mold
#3 Pack Mixture Tightly in Mold
with Press
#4 Add More and Pack Again
#5 Eject Block from Press
86 Cure (Dry)
B
B
Concrete Blocks
Concrete blocks are excellent for
foundations and walls. They are
made from a mixture of 1 part
cement, 2 parts sand and 4 parts gravel.
As manufactured commercially they:
l
are usually among the strongest
blocks available (in fact, they
are stronger than necessary for
l-story buildings);
l
have excellent insulating
qualities;
. are the most uniform blocks
(important for accurate, durable
construction).
However, they are by far the most
expensive block a community could
use.
Concrete blocks can be made locally
if limestone (or commercial cement)
sand, and gravel are available
in large quantities near the site.
The process is simple, but time-
consuming. Generally, the blocks
must be made about a month before
they can be used for construction.
Sand-Cement Blocks (Sandcrete)
Sand-cement blocks are strong blocks made of 1 part cement to 6-8
parts sand. They cannot be used to support .roof loads without
some reinforcement,
buildings. but are more than adequate for l-story
75
Because of the high proportion of sand needed, sand-cement blocks
are only practical for construction where there is a lot of
sand (sand-cement blocks are not generally made commercially).
But if the sand is available,
and efficient process. sandcrete block-making is a quick
cure (dry), Sandcrete blocks only take 12 days to
blocks. less than half the time required for concrete
76
Stabilized Ezwth Blocks
These are blocks in which clay soil, rather than sand, is mixed
with either cement or lime. The amounts of cement and soil
needed for a good mixture can only be determined by testing
how much the soil shrinks when dried (the procedure is simple
and can be followed easily by any community group).
The blocks are formed in the same
way as sand-cement blocks and can
be used for all the same purposes.
They are especially suited for low-
cost construction in areas where
sand is not available in large-
enough quantities for sand-
Crete. However, great care must
be taken to keep organic material
out of the clay soil used in the
mixture. Otherwise the mixture
will not form a strong bond.
(This too can be done with a
simple test of local soil
samples. See page 146).
Stabilized earth blocks can be
used after only S days of curing.
Summary
In surveying locally available materials, it is useful to keep
in mind that:
l
adobe brick is best for dry, hot areas but needs a rock or
concrete foundation and protection against rain;
. rammed earth walls, though made of the same ingredients as
adobe brick walls, are not as strong or as permanent:
0
stone and rock are good but require more heavy, hard work
than other construction materials;
l
sand-cement blocks are strong and easy to make, but they
require cement and a lot of sand;
l
stabilized earth blocks are cheaper than sand-cement blocks
and about as strong; but care must be taken to see that
the right mix of soils is available in the area;
. concrete blocks are good but very expensive if purchased
commercially;
to prepare; they can be produced locally but take a month
77
plain poured concrete is a strong and versatile material
especially suited to foundation footings, foundation walls,
and floors; it can be made inexpensively in most communities
if limestone or commercial cement is available;
reinforced concrete is the strongest, longest-lasting
material of all (especially in wet and stormy climates and
earthquake areas). But it is ~eryexpensive.
IhED PLANNING FOR C!QNSTRUCTION
8C
After the size and floor plan of a new building have been decided
on along with its site and position; and after a preliminary
assessment of the construction materials that may be used has
been made, the next crucial step is to develop detailed written
plans (or blueprints) to guide each part of the construction.
These plans must answer several questions about each part of
the building from the ground up:
FOUNDATIONS
l
How deep in the ground must the foundation be set?
. How thick must it be?
. How high must it be?
. What will the foundation be made of? Will it be
reinforced?
FLOORS
l
Will the floor be made of cement or packed earth? I
i
. How much should it be raised above the level of surrounding
ground?
. How thick should it be?
WALLS
* What will the walls be made of?
. How thick should they be? Should they be reinforced?
l
How will window and door frames be made and exactly where will
they be placed in each wal:?
ROOFS
. What will the roof be made of?
l
Will it be flat, set at an angle, or set at several angles?
81
Many of these questions are interrelated. For example, the
design of the foundation depends in part, on the weight of the
walls and roof it must support; and the design of the walls and
roof depends, in turn, on the foundation. Thus, in order to
plan the construction effectively, the builder must be able to
make some basic decisions about either the foundation or the
walls and roof before determining all their exact specifications.
When in doubt about a detail of the construction plans, the field
worker or community member may want to seek advice from an
experienced local contractor. In most cases, however, construction
plans ~o~be drawn successfully for simple l-story buildings
by anyone following the suggestions in this manual.
This part of the manual is designed to help the field worker or
community member,
Q first, to understand key methods/principles of construction
and key technical characteristics of basic materials;
. second, to proceed step-by-step to consider how these principles
and characteristics should influence their basic design; and
. third, to actually draw his/her own detailed construction
plans.
82
PLANNING FOUNDATIONS
If the walls of a building are
built directly on the ground
surface, the weight of the
building will soon press them into
the earth. This causes the
building to sag, crack, or leak.
Foundations are strong platforms
built below ground level, where
they won't sink. A building with
a foundation can "stand" securely.
The foundation of a well-
constructed building does
several things:
l
it provides a level platform
for the building to stand on;
a it helps protect the building
if earth tremors, strong winds
or rains shake the structure;
l
it keeps out water and damp-
ness.
Here's a list of things the
foundation must NOTdo:
l sag;
r --mm-----
t WALL
1
I I
I I
b FOOTING
I I
L- -e------ i
PLAN VIEW
ELEVATION VI EW
NOTE: The footing continues
around the building
l
dissolve (or rot) by water erosion;
l
crack from stress at a certain point;
l
slip on uneven ground
l
buckle under pressure of water
in the
ground (this
is
called
"scouring");
. collapse from the weight of
the building.
wall can be made of many different
materials. Each material must
be planned for in a different way.
Note:
There are other foundation
designs such as pier and beam, or
post and beam that communities
with access to heavy wood beams
might wish to use. See
Appendix 7 for reference
materials that discuss these
designs.
Footings
All foundations should have a
emcrete
footing. The concrete
can be poured directly into the
foundation trench, or into wooden
forms in the trench. In either
case, the bottom of the trench
must be ZeveZ and the sides of
the trench or of the kooden
forms must be square: that is,
they must be exactly ,vertical,
at 90° to the trench bottom.
INCORRECT: not square
TRENCH CORRECT: square
5cm x 1Ocm spacer
to secure the form
L 5cm x 1Ocm or 5cm x 25cm boards
at
right angles
to the trench botLzi” ang1e’
247-801 0 - 77 - 7
84
The
depth
of the trench in which
the footing rests depends on:
. what the foundation wall is made
of;
. the stability and strength of
the soil:
0 the frost line (this only applies
in areas where temperatures
drop below freezing in winter;
the frost line is the maximum
depth to which soil freezes
locally);
4 the unevenness and/or slope
of the ground.
The wCdth and thickness
of the
footing depend on what material
the foundation wall is made of.
Foundation Walls
The foundation walls can be made
of rock, or they can be made of
blocks of concrete, sand-cement,
or stabilized earth.
All of these materials are strong
enough to support the walls and
roof of most l-story buildings.
The choice depends on *what
materials are available, the
builders' budget, and whether or
not earthquakes or severe weather
conditions will require
reinforcement in the foundation.
INCORRECT: A crack wi 11 develop.
Rock Foundation Walls. A rock
foundation wall is built by setting
stones that are
20
to 40 cm.
long in mortar. The rocks must
be cleaned so that no rocks re-
main on them.
AZ2
the spaces
between the rocks must be filled
with mortar (these spaces are
called "joints"). In addition,
and most important, they must be
laid so they overlap. If a
straight line can be drawn between
the rocks from the top to the
bottom of the wall, a crack will
develop.
CORRECT : Overlapped is more durable.
85
Rock foundations are the least
expensive to build. However, they
require a large number of rocks,
and it is difficult to clean,
level, and overlap the rocks
properly.
If the building position is on
rocky ground, or on dry, well-
packed clay soil, the footing for
a rock foundation wall should be
4 to 8 cm. thick.
In less stable soils, such as
sand, or gravel, the footing
should be at least 10 cm. thick.
In soft black soil, drained
marshland, and made earth, the
footing should be reinforced and
should be 10 cm. thick.
In rocky or hard-packed clay soil,
rock foundation walls need only be
30
cm. deep. In other soils,
they should be at least 45 cm.
deep.
Rock foundation walls should be
at least 30 cm. thick, and they
will be much more stable if they
are flared at the base to 45 cm.
Block Foundation Walls. Whether
built of concrete, sand-cement, or
stabilized earth,.block foundal
tion walls are made by laying
level rows of blocks on concrete
footings until the wall reaches the
the planned height of the floor.
Each row of blocks, called a
cowse , is joined by mortar,
as are the ends of each block.
Block foundations cost more to
build than rock foundation walls
(except in areas where the rock
must be transported over large
distances), but block foundation
walls can be put up faster, and
they are easier to build well.
M 4CM
45cm
the footing must be entirely below
the frost line.
The table below gives suggested
depths to be safely below the
frost line in different climates:
Lowest Temperature Safe Minimum
in Winter, Degrees Depth for
Top
Celsius of Footing
-lo
45cn.
-so
75cm.
-1lO 90cm.
-18O 1.05m.
-22O
1.2om.
-28O
1.30m.
86
In rock or firm clay soil, a
block foundation should be 45
to 60 cm. deep. In less stable
soil, a block foundation
shouZd
NOT be used.
The width and thickness of the
footing depend on the size of the
blocks being used. In general:
.
the footing should be as thick
as the blocks are wide;
.
the footing should be 3 times
as wide as the blocks.
Frost Line. The frost line is the
depth to which the ground in any
area freezes in the winter. In
climates with freezing temperatures,
87
D
Sloping Ground. If a building is built at an angle on a slope,
-will tend to slide downhill, causing the foundation and walls
to slip and/or crack.
or is uneven, Thus if the ground under a building slopes
the trenches for the foundation footing must be
completely levelled.
--------- DIRECTION OF SLOPE
---- --- b
------- ---------- ---
If the ground slopes sharply, it may be easier, or necessary, to
"step" the trenches. When block foundation walls are planned,
it's important to make each step the height of one or two courses
of blocks.
88
Deciding Upon the Ma+-Gals and Qimensions for Foundations
In general, the best way to decide what the foundation walls
will be made of is to choose the least expensive and most easily
accessible material.
Once the choice has been made between rock and blocks, the
depth of the trenches and the dimensions of the footing and
foundation wall may beqprozimatety determined by using the figures
outlined on pages 85-86.
It is important to remember, however, that these preliminary
figures are only approximate guidelines. Any number of local
conditions can make a deeper, stronger foundation advisable.
One of the best ways to determine whether preliminary foundation
plans are safe is to compare them with the foundation structures
of buildings in the local area.
member should ask: The field worker or community
, How deep are the foundations of buildings that have cracked
walls or other signs of weakness?
of buildings that have lasted well? How deep are the foundations
0
How wide and thick are the foundation footings and walls
of weak buildings ? Of strong buildings?
. What are the foundations of weak buildings made of? What
are the foundations of strong buildings made of?
If preliminary plans for the foundation are similar to those
of strong buildings built nearby on the same kind of soi1.i.n the
local area, they should be safe to use. If the preliminary plans
are similar to those of weak buildings they should be strengthened
before the start of construction.
Drawing Final Foundation Plans
After the materials and dimensions
of the foundation have been planned,
the last step before construction
of the foundation can begin is
to draw a final foundation plan.
The plan should include two simple
drawings:
- a scale drawing of the footing
and foundation wall as they
would look in a cross-section;
-
-W FOOT I NG
4 FOUNDAT I ON WAL:
Q
89
- a scale drawing of the footing
and foundation wall measurements I
as they would look if seen from
above.
Both these drawings are simple to
produce with a ruler. tl
Step-by-step
instructions will be found in
Appendix 2.
OUNDAT I ON WA
E
9
90
In areas of heavy rainfall, if the
floor is at or close to ground
level, water will come in under the
doors and damage the floor.
For both these reasons, the floor
of all buildings in areas where
there is heavy rainfall should
be raised at least 20 to 30 cm.
above ground level to protect it
from moisture.
The best way to do this is with
"dry fill."
Dry
fill is a layer
of any material that will not hold
water. Typical materials used for
dry fill include: small stones,
broken bricks, clumps of hard
earth, and gravel.
Types of Fkxws
Two basic types of floors will be
discussed in this manual:
. hard-packed earth floors,
0 concrete.
In areas with large local wood
supplies, wood floors are also
good.
To be comfortable and safe, the
floor of a building must be:
0 dry;
. level;
l
smooth, but not slippery:
movement should not be
obstructed by holes or bumps,
but the surface should not
become slippery when wet.
The most important of these is
keeping the floor dry.
In many climates, the ground
under a building will be damp,
even in periods between rainfall.
WATE R
ICORRECT: Raised to Prevent Flooding
D
I
HARD-PACKED EARTH FLOORS
Hard-packed earth floors are much
less expensive than concrete.
They are adequate in dry climates,
but can be uncomfortable and
unhealthy in wet climates or low-
lying areas, even when ample dry-
fill is used.
Earth floors must be made from
hard earth taken from below ground
level. Soft topsoil, or any soil
containing organic material will
not pack well enough. The hard
earth should be placed above the
dry fill in a tightly-packed layer
lo-15 cm. deep.
CONCRETE FLOORS
Concrete floors cost more than hard-
packed earth. They are also stronger
and much better-suited to wet climates
and low-lying areas.
A concrete floor is made simply by
pouring a layer of concrete over
the dry fill.(Hard laterite is the
best kind of fill for a concrete
floor.) The.best thickness of the
concrete layer depends on the
planned use of the floor (see
table on right).
Suggested Thicknesses
of Concrete Floors
Purpose of Thickness
floor cm.
house, clinic, 10
school
garage 12.5
(for vehicles)
farm storage 15
(heavy equipment)
92
In locations where the ground is very unstable or uneven, or in
earthquake zones, a concrete floor might need reinforcement for
flexibility and additional strength.
Estimating the Amount of Concrete Needed for a Floor.
To determine whether the builder can afford a concrete floor, and
,to be sure of buying enough materials without buying too much,
the field worker or community.member(s) should make an estimate
of how much concrete will be needed. Step-by-step instructions
for the calculations needed will be found in Appendix 3.
PLANNING WALLS, WINDOWS, AND DOORS
A cqlete, detailed plan for the construction of a building's
walls (both exterior and interior) would include descriptions
of:
l
the material they'll be made of;
l
their height;
l
their length;
. their thickness
l
the exact placement of windowsp doors;
_I
. the construction techniques to be used, especiallyaround
doors and windows, and where any two walls meet;
l
the use of reinforcement (if any) to help the building
withstand the stress of very soft ground, high winds, or
earthquakes:
a
an estimate of the amounts of materials needed for
construction.
The basic plan and design of the walls developed earlier should
already specify many of these features, especially the materials
the outer walls will be made of, their dimensions, and the exact
placement of doors and windows.
However,, especially when blocks or bricks will be used for the
walls, some changes may have to be made before construction
can begin. To avoid expensive mistdkes or problems during
construction,
be prepared. a detailed construction plan of the walls should
93
B
Wall Height end Length
When the walls will be made of rammed earth, stone, concrete,
bamboo, or any other material other than block or bricks, the
height and length of the walls should be exactly as planned in
the basic wall design.
However, when using blocks of any kind (adobe, sand-cement,
cement, etc.) it may not be possible to build a wall exactly the
height and Zength planned.
B
For example, if the blocks used will
measure 12 cm. high, a wall could
be
2.88
meters
(24
blocks) high
or 3 meters (25 blocks) high;
but it couldn't be 2.96 meters high
unless one layer df blocks was
cut in half, and this is difficult
to do. In the same way, if the
blocks used will measure 40 cm.
long, a wall could be 7.20 meters
(18 blocks) long or 7.60 meters
(19 blocks) long; but it couldn't
be 7.35 meters long unless one
block in each layer of the wall
were cut 5 cm. short.
2.88m (24 Blocks) -
211
Construction is much easier, and much less expensive if the
height and length of block walls are adjusted so that they
can be made from a whole number of blocks.
To determine how much the height and length of the walls needs
to be adjusted (if at all) simply follow these steps:
STZP I:
Divide the planned height of the wall .by the height of
one block. If the answer is a whole number, the wall can
be built as planned without any adjustment. The result
of the division will equal the number of layers (courses)
of block needed to reach that height.
Example: The planned height of the.waZZs Ls 2.88 meters (288 em.);
us&~-22 cm.'high bLocks:
288 i 12 = 24cou.rses of blocks
If the answer is a whole number plus a remainder, compare
the remainder with the height of one block and round off
to the nearest whole block.
94
Exam@?e: of the planned he<ght 01’ the walls is 29Ocm. h{gh,
udng
12
cm. high blocks:
290 + 12 = 24 whole courses +
c.2 remahder of 2 cm,
The remainder of
2 cm. is less
than
l/2
of 12 cm. (the
height of one block), so rowa? the height of the watts
down to 24 bi!ocks hCgh.
Example:
If
the planned height
of
the wa.Us is 295cm., using
12
cm. h$gh blocks:
295
+ 12 = 24 whole courses +
CL zwmdnder of
7
cm.
The zwmdnder of
7
cm. 7:s more than l/2 of 12 cm., so
round the height
of
the &!Zs up to
13
bl.oL>ks high.
STEP 2:
The procedure for adjusting the
length
of a blor?k wall is
similar to the procedure outlined above for adjusting
the height: divide the planned
length
of the wall by the
tength
of one block. If the answer is a whole number, with
no remainder, the wall can be built as planned without
any adjustment. The result of the.division will equal
the number of blocks needed to reach that length.
#!iMlpZe:
If
the ~~LVUWI length
of
the natt
is
7.2 meter8 (720 Qn. i,
U8iw
40
an. hq blocks:
720 ; 40 = 18
blocks Zag
If the answer is a whole number plus a remainder, compare
the remainder with the length of one block and round
up or down to the nearest whole number of blocbs.
Wall Thickness
The thickness of a wall depends on three things:
l
whether the wall is exterior or interior: interior walls.
usually do not support the weight of the roof and can
therefore be thinner; interior walls also play a less
important role in insulating the building from heat and cold;
. what the wall is made of: walls made of stronger materials
can be thinner than walls made of weaker materials;
l
the climate: buildings in desert-like climates need thicker
walls, while buildings in tropical climates need thinner
walls.
95
The table below suggests minimum thicknesses for different kinds
of walls. The figures given should be adequate for most l-story
buildings (up to 5 m. X 9 m.). However, if there is any doubt
about the load-bearing capacity of the walls in a special design,
advice from an experienced local contractor should be sought.
SUGGESTED WALL THICKNESS FOR DIFFERENT MATERIALS
Material Exterior Wall Interior Wall
Rammed Earth 37.5-45 cm. 37.5-45 cm.
Adobe Brick 30 cm. 30 cm.
Poured Concrete 12.5-20 cm. 12.5-20 cm.
(not reinforced)
Poured Concrete 12.5 cm. 12.5 cm.
(reinforced)
Stone 30-37.5 cm. 25 cm.
Block (sand- 20 cm. lo-15 cm.
cement, stabi-
lized earth,
cement)
Placement of Doors and Windows
As with the height and length of walls, the exact placement
and size of windows and doors may have to be adjusted to make
construction easier. No adjustments need to be made when the
walls will be made of rammed earth, stone, concrete, bamboo,
or any other material other than block or brick.
However, when using blocks of any kind (adobe, sand-cement,
cement, etc.) the size and placement of windows and doors should
be planned,so as to make them even with the courses of blocks.
ADJUSTING THE SIZE OF WINDOWS, DOORS
The procedure for adjusting the height and width of the space
for windows and doors is exactly the same as the procedure for
adjusting the height and length of a wall. Simply think of the
windows and doors as though they were walls to be built with
blocks. Then, following the procedure described on pages 93-94,
increase or decrease the height and length of the windows/doors
as necessary.
For example, suppose a window is
planned so that it will begin
135 cm. from the bottom of a wall
made of 10 cm. high x 20 cm. thick
x 40 cm. long blocks. 135 cm. would
be 13s layers (courses) of blocks
high. So rather than cut a whole
layer of blocks to fit the window
height, it is much easier either
to raise or lower the window 5 cm.
so it will start 130 cm. (13
courses) or 140 cm. (14 courses)
from the bottom of the wali.
LOCAT
LO CAT
I ON
I ON
Construction Details for Dams,, Windows, an,d interior Walls
DOOR AND WINDOW FRAMES
The construction plan for walls
should show how the door and
window frames will be attached
to the walls.
Window and door frames are made
of wood (5 cm. thick wood is
best) to fit the exact size of
the wall opening. The frames
are permanently attached to the
walls, and then the windows and
doors are attached to the frames.
WINDOW FRAME
DOOR FRAME
Frames that are nailed right to the
masonry or concrete of the wall are
the best for preventing drafts and
leaks. But they may also be
attached to the wall by placing
wooden slats in the mortar joints
and nailing the frame to the
slats.
WINDOW FRAME
LINTELS
-T-
Lintels are short beams that should
'always be used to support the wall
over an opening for a door or
window. Lintels are usually as
thick as the wall. I
In rammed earth or
walls, the lintels adobe brick
may-be made of
5
cm. thick wood beams. They
should extend past the window or
door opening about 20% of their
length, or a minimum of
2C
cm.
on each side.
In walls made from any other
material, except bamboo, the
lintel should be made of reinforced
concrete (use two steel bars for
reinforcement). Construction
will be much easier if the lintels
are "pre-cast": that is, made in
advance and then placed in the
wall like a brick. (For bamboo,
see the section on bamboo con-
struction, page 181)
l
In block walls
the lintels should overlap the
opening 3 the length of a
block on either side of the
frame.
I INTEL IN WOOD FRAME
REINFCRCEMENT BARS
98
INTERIOR WALLS
Interior, or "partition" walls do
not support the weight of the roof,
as the exterior walls do. Thus they
are often thinner than the outer
walls, or made of 'a different
material completely. However, they
must be attached to thrt outer walls.
This can be done after the outer
walls have been built. But it is
usually better and easier to build
all the walls at the same time.
This is especially true when the
walls will be made of blocks or
bricks.
The wall construction plan should
include a diagram showing how the
partition walls will be attached to
the outer walls=
REISJFORCBMENT . , , . . . .
In areas where buildings are
exposed to stresses suqh.as high
winds, severe storms, freezing
temperatures, and high humidity,
walls should be reinforced.
Effective reinforcement will increase
the life of any building sig-
nificantly. Often it enables the
builder to construct thinner walls
and save money on materials.
In earthquake areas, walls
MUST
be reinforced. (See the,section
on construction in earthquake 'zones
for special reinforcement techniques
not shown here, page 195). _,
Rammed earth and stone walls are
very difficult to reinforce
effectively. Block walls can
be reinforced in several ways:
l
steel rods can be run along
the horizontal joints of the
wall.: the rods should be.1 to
1.25 cm. thick: where they over-
lapI the overlap should be at
least 25
cm.
RE COMMEN DE D
EXTERIOR WALL
m( EXTERIOR WALL
A INTERIOR WALL
-NOT RECOMMENDED:
WEAKER
RE I N FORCEMENT BARS
.lN MORTAR JOI NTS
(overlap 25cm Minimum)
99
. barbed wire is an effective
reinforcer: it is run, like
the steel rods, along the
top of each course of brick:
. if hollow blocks are used, the
holes in the corner blocks can
be used to run steel rods from
the foundation up to the roof;
then the holes can be filled
with concrete;
REINF
.a "ring beam" can be run
around the top of the walls:
this is usually a 15 cm.
thick band of concrete with
2 steel rods that runs
continuously (without seams)
around all four walls. Ping
beams are mandatory in
earthquake areas. (See
page 200).
Poured concrete walls are often
reinforced; the exact thickness
and arrangement of the
reinforcement bars should be
determined by an experienced
local builder, but this is the
method most commonly used:
Steel rods ranging from l-2 cm.
are arranged horizontally and
vertically, lo-20 cm. apart.
They are fastened to each
other by lightweight flexible wire
and are wired in place temporarily
until the concrete is poured.
Concrete that has been reinforzed
has from 2 to 5 times the strength
of unreinforced concrete. This
means that, for example, a 10 cm.
thick reinforced concrete wall will
be as strong as an unreinforced
wall twice as thick.
RE
RING
INFORCEMEN
TOP OF
RE I N FORCEMEh-J’ BARS
POURE
RE I NFORCEMENT RODS .
:D CONCRETE w
. the basic roof styles; their advantages and disadvantages
for the local climate and environment;
. the kinds of materials suitable
for each roof style;
0 how to design and build each
roof style.
Roof Styles and Their Functions
All roofs provide protection from
the el?Fiii?nts: sun, rain, wind, dust,
heat, cold, and animals and insects.
But each different kind of roof
protects against some things better
than others. In addition the
different roof styles vary in
their durability and ease of
construction.
r
FLAT ROOF
ESTIMATING MATERIALS tiEEDED TO BUILD WALLS
Before construction can begin, the builder needs
to estimate
how much of each of the materials to be used will
be
needed
so that all the supplies can be purchased or assembled in
time.
Details of the calculations involved will be found in Appendix
4.
PLANNING ROOFS
When the basic design and construction plans for the foundation,
floor, and walls are complete, the field worker and community
member(s) should consider what kind of roof the building
should have and how it will be constructed.
There are several kinds of roofs. Each can be made of different
materials, and each has advantages and disadvantages, depending
on the
climate,
the builders' budget, the availability of
materials, and the ease of construction. To make a good decision
about the kind of roof to be used, the builder needs to know:
There are four basic roof styles:
@flat:
the roof simply lies flat
across the top of the building's
walls;
SHED ROOF
. shed:
the roof is built at a slight
angle, generally from lo-30".
l
gabZe or double-pitched:
the roof
forms a triangle over the building,
dabie
roofs are a combination of
two shed roofs, each starting from
the opposite sides of the building
with the same angle or pitch,
hence, "double-pitched";
l
hipped:
hipped roofs are gable
roofs that have been pitched
on the ends of the building
as well as the sides.
FLAT ROOFS
Flat roofs are generally the most
difficult to build and the least
suitable of roof styles, especially
in buildings wider than 4-5 m.
Here are some of their principal
disadvantages:
. because they are flat they tend
to sag in the middle unless
given very strong support:
the most common forms of
support, wooden or reinforced
concrete beams, must be heavy
to be strong: as a result
they are difficult to lift
into place; reinforced concrete
or heavy woodcotwmrs may also
be used to support flat roofs.
However, columns reduce usable
space inside the building;
. flat roofs tend to hold snow or
rain; this increases the weight
on the beams and walls and leads
to leaks and warping;
. flat roofs tend to lift in wind
and must be securely tied to
the building; in areas with
severe storms, flat roofs
are dangerous.
The only advantage of flat roofs is
that they can provide extra living
space above buildings in dry,
desert-like areas.
I I I
GABLE ROOF
HI P!‘ED ROOF
SHED ROOFS
Shed roofs are generally easier to
support than flat roofs. They are
build.
Because of their pitch (angle),
they shed water easily and are
particularly good in warm, rainy
climates with no snow.
usually the least expensive and
the easiest style of roof to
Shed roofs are slightly less
subject to wind pressure than
flat roofs. However, in stormy
areas they must still be very
securely tied down to the walls.
G-ABLE ROOFS
Gable roofs use more materials,
require more care in design, and
are more expensive than shed roofs.
However, they can be built over
large areas (buildings over 10 m.
wide) without heavy beam or column
support because they are made of
relatively light materials and
are extremely strong.
Gable roofs are much less affected
by wind than flat or shed roofs
and are therefore better-suited to
areas with strong storms.
10 3
In addition, gable roofs provide
excellent insulation against heat
and cold. In areas with cold
nights or seasons, the triangle
formed by the double pitch above
the ceiling helps hold the heat in
at night. In very hot areas, gable
roofs that are ventilated have the
opposite effect: they pass heat
out of the building quickly,
thus helping to keep it cool.
In general, gable roofs are the
best, and most adaptable style
whenever they are within,the
builder's budget.
HIPPED RtiFS
Hipped roofs provide more protection
auainst wind on the ends of a
But this is their only advantage
over the other roof styles. Hipped
roofs are harder to design, harder
to construct and use more
materials than any other roof
style.
Roof Materials
b&.lding than do gable roofs.
Roof materials fall into two categories: those that are used
for the frame and support, and those that are used as the roof
covering.
WOOD
Wood is the most common material used for roof frames and supports
because it is strong and easy to work with. When the covering
material will be heavy (tile, for example), wood may be the onZy
practical material for the frame and support of the roof.
One caution: before planning to build a wood frame, or to use wood
beams for roof-support, make sure th,at wood is available in
sufficient quantity and size. Wood beams must be at least 5 x 15
cm., and wood used in frame construction should be at least 5 x
10 cm. To estimate the quantities of wood needed for any roof
design, see pages 107-114 on roof construction plans.
BAMBOO
Bamboo is an excellent frame
material, especially where resistance
to wind and earthquake are important
concerns. It is light, flexible,
and strong.
Where large species of bamboo
are available, they, zan be cut
to make tiles for a roof
covering.
The chief disadvantages of bamboo
are:
a it cannot be easily nailed:
most connections are made by
tying section together with
wire, thongs, or hemp lashings;
. it tends to rot when exposed to
dampness or rain.
105
MUD
Mud is the least expensive roof covering, but it has serious
disadvantages: it is very heavy; it tends to develop cracks that
cause leaks,and it requires very frequent repairs to prevent
collapse.
106
TILE
Tile roof coverings are also very
heavy. The materials and labor
involved make tile very expensive.
Tile roofs should not be used in
earthquake zones.
REINFORCED CONCRETE
This kind of roof is seldom needed
on small buildings. If it is
required, an engineer must be
consulted on its design.
CORRUGATED METAL OR ASBESTOS
Corrugated iron, aluminum, zinc
and asbestos sheets have several
advantages as roof coverings:
. they are very light;
. they are easy to use on shed
or gable roofs;
. they are usually leak-free;
. they are relatively fireproof;
. aluminum sheets are rust-free.
On the other hand, they have some
disadvantages, especially on flat
roofs:
. they are cold in winter and hot
in the summer;
. they rust (except for asbestos
and aluminum);
. they are noisy during rain;
. they tend to tear away easily
during heavy storms or wind;
. asbestos has been identified
as a possible cause of cancer.
THATCH
Thatch is an effective and
inexpensive covering for wood
or bamboo frames. It is light.
In addition, it provides better
insulation against heat and it is
quieter than metal.. However, thatch
will not last as long as other roof
coverings, especially in wet
climates. It is also easily
infested by animals and insects
unless treated with an effective
insecticide.
Construction Details for Roofs
FIAT ROOFS
Flat roofs are built in three major steps:
S!l’EP
I: Placement of the beams across the width of the building:
Wood beams should be about 5cm x 15cm. If bamboo is used
beams should be made from the thickest stalks available.
For heavy materials such as tile. place the beams at
least every 0.6 -- l.Om. For lighter covering materials,
the beams can be slightly further apart if desired. Each
beam should be as long as the building is wide plus the
length of overhang on both sides of the building.
S!TEP 2:
Place purlins across the beams: Purlins are horizontal
pieces of a roof frame that support either the roof
covering material (in flat and shed roofs), or the
pitched rafters (in a gabled or hipped roof). Each
purlin should be as long as the building plus the length
of overhang on both ends of the building.
STEP 3: Cover the roof with the planned covering material, tying,
bolting, nailing, or lashing it securely to the purlins.
108
SHED ROOFS
Shed roofs can be built in two ways.
Either wayr the beams for support
can be both thinner and further
apart than for flat roofs:
. If one wall going the length
of the building is higher than
the other, the shed roof can be
built with beam supports like
flat roofs;
S I MP LE BEAM SUPPORTED
SHED ROOF
.
A much stronger shed roof can be
built if the building walls are
level. Beams are laid across
the walls. Then pitched rafters
made of 5 x 10 cm. wood planks
are supported at an angle by
four struts. Finally, the
purlins are attached as in the
flat roof and the covering
material is tied to the
purlins:
TRUSS SUPPORTED SHED ROOF
GABLE (DOUBLE-PITCHED) ROOFS
Gable roofs are supported by
light weight wood, bamboo, or
steel structures called trusses.
Basically trusses are triangular
shapes strengthened by struts
that help distribute the weight of
the roof and the force of wind,
rain, snow, and earthquake evenly.
The illustrations on this page and
the next show how trusses are used
and identify their key parts. See
the glossary on the next page for
definitions of each part.
LO9
GABLE ROOF: WITH PURLINS ATTACHED TO TRUSSES,
AND USING END WALLS AS TRUSS SUPPORTS
110
GLOSSARY OF TERMS FOR GABLED‘ROOFS AND TRUSSES
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Cross ITie:
Abeam pladed horizontally across the width of the
building and tied to the walls on each end. The cross
Eczve : tie is the bottom part of a truss-triangle.
PurZh: The part of a roof that overhangs the wall.
Rafter:
Horizontal beams that tie the trusses together. (Not shown)
Either of the angled parts of the truss.
RQfteP Batten:
A short beam that joins the top of the rafters
in
a truss.
Rafter hzcketr
A short beam that supports the rafter when
Ridge:
there is a large overhang.
SpZke: The top point of the truss (also czlled the cqxx).
A section in a rafter where two long pieces of
wood are joined together with nails and a short
piece of wood.
strut:
Any short beam attached to the cross tie and rafters
of the truss and used to provide strength.
mss : One of several triangular support-structures used
to hold up a gabled roof.
WQZZ
Phzte:
The part of the wall to which the roof frame is
attached.
Sample Truss Plans
The following pages show the plans for two different trusses for
a gabled roof.
The first plan is for roofs on buildings
6
to 9.6 meters wide
(20-32 feet in U.S. measurements). The second plan is for
buildings up to 6 'meters wide (18 feet in U.S. measurements).
In either case, the trusses should be placed 2 meters apart.
The charts accompanying each plan indicate the length of each
part of the truss for any given building width.
Note:
The charts were originally prepared in U.S. measures.
Field workers in areas using metric measures should try
to find similar charts and plans in their local area,
since standard lengths may not be comparable. If metric
. charts are unavailable, the charts printed here may be
used.
111
TRUSS PLAN FOR BUILDINGS 6 -
9.6
METERS WIDE
BUILDING
WIDTH,
Meters
W
6.0
6.6
7.2
7.8
8.4
9.6
ESTIMATING LENGTH
OF MEMBER,
Meters
L 2A 6
3.75 4.38 2.32
4.05 4.72 2.52
4.35 5.05 2.75
4.65 5.40 2.95
4.95
5.80 3.15
5.25 6.10 3.35
5.55 6.45 3.55
C
1.25
1.35
1.45
1.55
1.65
1.75
1.85
CONSTRUCTION
Distance Between
Bolt Connections
D A 6
2.10
1.83 2.11
2.30 2.00 2.31
2.50 2.16 2.51
2.70 2.34 2.71
2.90
2.52
2.91
3.10 2.69 3.11
3.30 2.87 3.31
C
1.05
1.15
1.25
1.35
1.45
1.55
1.65
113
114
I
TRUSS PLAN FOR BUILDINGS UP TO
6
METERS WIDE
1
3/4"
BOLT
6"
Lona
PURLINS
ROSS 7-I C
RING BEAM
I.-. . .
UUNU l5tHM
BOLT
4"
LONG
3” BOLT/M. S. ROD I I
EUILhNG
WIDTH,
Meters
3.6,
4.2
4.8“
ESTIMATING LENGTH
OF MEMBER,
Meters:
i
A
IB‘. c
4.35
1.30 2.85
4.95 ! 47:
3.20:.
5.55
..:5 3
.,:i>
6.15
f 52. s:90
JhSTRUCT I ON
Distance Between
Bolg Connect ions
I
A
B e
I
3.3 1.16
2.29
4.5 1.33 2.65
- :
5. I
1.51 2.99
5.7
1.67
3.35
BOLT
Long
\‘:,.. _::. .-. \ /
3 DlRECTlONS FOR CONSTRUCTION
Once the construction plans for the entire building are complete,
construction
can begin.
This section is designed to help the field worker and community
member(s) organize their work to make the construction process
flow smoothly, and to provide step-by-step directions for the
critical parts of construction that are common to all buildings.
The material is divided into six parts:
. SETTING OUT (LAYING OUT)
. FOUNDATION FOOTINGS
. FOUNDATION WALLS
. FLOORS
. WALLS, WINDOWS, AND DOORS
SETTING QUT ClAV!~G tX.JT)
In order to begin digging the
trenches required for a building's
foundation, the builder must first
transfer the lines and measurements
indicated on his or her foundation
plan to the building site. That is,
the exact length, width, depth, and
position of the foundation trenches
must be marked on the ground.
This movement from the plan to the
actual site is called setting out.
It is probably the most critical
step in the entire construction
process.
FLOOR PLAN
D
A building that is set out
accurately will be:
o level: no part of the floor or
foundation higher than
another;
l
square:
walls parallel and the
same length;
~plumb: straight up and down, not
leaning to one side or
the other
NOT THIS THIS
THIS
r---- >THlS
_____ -___---.
117
118
A building that is set out
carelessly will be difficult or
impossible to construct according
to plan. As a result, the finished
structure may be expensive to
maintain and unhealthful. So it is
important to take special care when
setting out.
There are three major steps to
setting out:
.Orientation
of the building on
the site;
.MzrkGzg a simple outline of the
building's foundation on the
ground;
l
PZacing
"batter boards" aromd
the foundation outline and
marking the position of inside
walls, doors, and windows on the
boards.
TAPE MEASURE
The tools shown on this page are
needed to set out a building so that
it will be level, square, and
accurately measured.
PLUMB BOB
LEVEL BOARDS
(5cm x 1Ocm x 1.5m)
NAILS
I-
119
Orientation
The orientation of a building is the
direction its front walls face:
north, east, south, west or
something in between.
To mark the orientation on the site,
first find north. This is easiest
with a compass. But if no compass
is available, finding north is still
fairly simple.
The builder should stand at the
SUNSET ,
building position so that his/her
1 I
right arm points at the spot where
the sun rose in the morning while
the left arm points to where the sun
set the last night. In this position
the builder will be facing north.
Standing in the same position, if the
builder moves his/her arms so they
form a straight line to the sides,
they will be pointing due west (left
arm) and east (right arm).
Once the main compass points have i
been established, use a stick to mark
out the shape and position of the
building. Add about 2 meters to the
dimensions of the building on all
sides: the extra space will be needed
for supplies and work space during
construction.
Next, clear the ground inside this
area of trees, shrubs, and loose
plant growth. If the topsoil is
loose, clear away the top 15cm or so Y
to get down to hard earth: loose soil
will not support a building.
If clearinq the lan d at the positi
PROXIMATE BUILD;
outlined proves too difficult, or
if it would require felling trees
that are desired for their shade or
beauty, consider moving the building
a short distance before clearing the
land.
120
iMarking the Fsundatiosa Qutline
The next step is to mark the outline
of the foundation on the site using
string and pegs.
Three measures are very important:
* the length of .each wall must be
marked exactly:
* the string must be exactly level;
* the corners must be square:
exactly
90°
The length
of each
wall
is easy to set
out on level ground. Simply measure
it with a tape measure, making sure
to pull the measure tight.
CORRECT
INCORRE’;T : NOT ACCURATE J
When the site is onwzevenground,
care must be taken to measure the
length of the wall along a level
line: following the slope of the
ground will throw off the measure-
ments.
121
To
prevent errors, begin at the
highest end of the first wall's
length and attach the string to a
peg planted at the end-point. Set
a new peg every 2 meters to prevent
the string from sagging, and test to
make sure the string is level by
using a plumb bob and mason's square
as shown: when the plumb bob stops
swinging it will be plumb (straight
up and down); the string will be
exactly level when it is a 90° to
the bob string.
Repeat this process until the
length of string set out is equal
9
to the planned length of the first
wall.
-----MB BOB
If the ground is sloped
very steeply, it may be
easier and more accurate
to measure the wall's
length in steps or
stages. To do this run
a new length of string
from the bottom of every
second peg (that is,
every 4 meters). Test
with a plumb bob to be
sure that every peg is
straight up and down.
In addition, to be sure
there are no gaps or
.overlaps in the measure-
ment of each new stager
piant a small block with
a circle on it right
next to every other peg:
then in measuring the
next stage (or step)
along the wall, hold the
tape measure to the point
in the circle that marks
the end of the last stage.
Once the first wall has been set out
the second wall should be set out at
right angles to it (900). There are
several ways to make sure that this
angle, and the angles between all th
walls set out are square:
s
A mason's square is good for
distances up to 3 meters. Use it
to get started, but don't use it
to check the entire outline.
. One of the easiest and most
accurate methods of checking large
distances for squareness is to
compare the diagonals. Simply
measure the diagonal lines from
Opposite corners of the foundation
When they are exactly equal in
length, all the angles will be 90°
On uneven ground, be sure to use
the tape measure along a level
line!
. If measuring the diagonals is
inconvenient, or if the building
is not a simple rectangle, another
method is the 3-4-5 calculation:
If the wali on one side of a
right angle is 3 units long
and the wall on the other side
is 4 units long, a-line drawn
between their ends wit2 always
be
5 units long.
Here's how to use
this rule to test whether the
angle between two walls is
square: Along the string set
out for one wall, measure and
mark off 1.5 meters (3 x .5m).
Then, along the string set out
for the second wall, measure and
mark off 2 meters (4 x .5m).
Next, measure and cut a piece of
string 2.5 meters long (5 x .5m)
and hold its ends to the Faints
marked off along each wall.
When the 2.5 meter string just
touches both marks with no slack
left over, the angle between the
two wall strings will be exactly
square. If the 2.5 meter string
is too short or long, adjust
either one of the wall strings
Until it fits exactly.
TRI ANGLE
:-KING THE INSIDE FOUNDATION LINES
Once the outside walls of the
.foundation have been set out with
pegs and string, the next step is
to set out a second set of lines to
mark the
inside
of the foundation
walls. Use the same procedures to
keep them level, accurate in length,
and square.
The easiest way to begin is to
measure the width of the foundation
wall and mark it along the strings
set out for two opposite walls.
Then set out a string between these
two points and fasten the ends with
pegs. Use a plumb bob to be sure
each peg is directly beneath the
outside foundation line.
Next, repeat this process for each
of the remaining walls. Place a
peg at every point where the new
lines cross: these are the inside
corners of the foundation walls.
Batter Boards
Batter boards are like a single rail
fence placed around the building
position. They should be placed
after the foundation lines have been
set out and before any digging for
construction begins. Batter boards
are essential for two reasons:
. They provide permanent reference
points for the position of the
foundation walls: these will be
needed once the string markings
have been removed during
construction;
l
They can be used to measure and
mark off the exact position of
doors, windows, and floors, thus
making it much easier to build the
walls accurately.
To be useful, batter boards must be
exactly
le\rei
and should be set
about 1 meter back from the string
marking the outside foundation line.
123
124
PLACING BATTER BOARDS
To place batter boards around the
building postion, first find the
highest point on the site about
1 meter outside the outer foundation
line and place a wooden stake firmly
in the ground.
Nail the first board to this stake
so that the
top
of the board is at
least as high as the top of the
foundation walls will be. Since the
foundation walls must be as high as
the floor, this will be at least
20-30cm.
above the ground.
Next,
place a second stake 2 meters
from the first and 1 meter outside
the outer foundation line. When this
stake is secure, nail the other end
of the first batter board to it,
taking care that the batter board is
level. Nail a second board to this
same stake and repeat the process of
placing new stakes, levelling, and
nailing the boards, until the batter
boards form a fence that goes
completely around the -building
position.
AS THE PLANNED
125
HOW TO LEVEL BAT':,'? BOARDS
A commercially made "spirit level"
is the easiest levelling device to
use. Place it on the surface - in
this case the top edge of the
batter board - and keep adjusting
the height of the board at the
opposite end until the bubble is
in the center.
When joining boards at stakes,
SPIRIT LEVEL
When Air Bubble
is Between the
Hair1 ines the
Boards ar; Level \\
place the level over the
seam
of the
board to maintain a continuous level
line.
An additional check on level can be
made at the corners: use an extra
board to provide a surface for the
level.
Another method is to use a water
level: this is a clear plastic hose
that is filled with water. Adjust
the first end of the hose to a known
level mark. When the other end of
the hose is placed at the next stake,
the water inside will be at the same
level as at the first end. To
prevent spillage the ends
may
be
plugged until the hose is in position.
But all plugs
must
be removed to get
an accurate measurement.
TRANSFERRING MARKS TO BATTER BOARDS
Once the batter boards are complete,
all the measurements shown on the
written foundation plans should be
marked on the boards.
First, transfer the foundation lines
marked by the strings set out
earlier: run a strinq from one board
to the opposite board directly over
each foundation line. Use a plumb
bob to make sure this new string is
over the corner pegs.
Next
tops
sect
I
place nails or saw
of the boards where
the strings.
cuts
in the
they inter-
A'good system is to use different
marks for the foundation lines than
those to be used for other
important measures such as wall lines
and the positions of doo::s and
windows. For example, use small
notches cut with a saw to indicate
the foundation lines. Then use nails
to indicate the wall lines.
Once the foundation lines and *:lall
lines have been marked on the batter
boards, the builder is ready to
start digging the foundation trenches.
Note: the digging will be easier if
the strings are left in place until
the trenches have been well started.
CONSTRWCTIQN OF FOUNBATlON FOOTINGS
Digging the Foundation Trench
Before the concrete footing can be poured, the builder must dig a
trench for it. The
depth
of the trench depends on characteristics
of the site and building that should have been determined in the
basic planning stage (see pages 82-88).
However, the
width
of the trench, and the care with which it must
be dug depend on whether the concrete footing will be poured
directly in the trench or into wooden forms.
TRENCHES FOR FOOTINGS POURED WITHOUT FORMS
When wooden forms will not be used,
the trenches must be dug very
carefully:
. the walls of the trench must be
plumb (straight up and down);
l
the earth forming the trench
walls and bottom must be very
firm so that there is no danger
of the trench crumbling when the
concrete is poured:
. the earth must be removed
carefully so that the earth at
the bottom of the trench is
smooth, clear of all trash or
debris, and undisturbed
(undisturbed means that the
earth has not been moved,
) RI GHT
loosened, or dislodged by the
digging);
. the bottom of the trench must be
absolutely level: 6-8 measurements
with a straight board and level
should be made along the length of
the trench to be certain of the
level;
0
the trench must be exactly as
wide as the concrete footing;
. the trench must be free of
UND I
standing water.
127
128
TRENCHES FOR FOOTINGS POURED WITH FORMS
It is much more common to use wooden
forms when pouring the concrete
footing because the ground at
building sites is rarely hard enough
to stay in place when the concrete
is poured directly in the trench.
Like the trenches for non-form
footings, trenches in which forms
will be used must be level at the
bottom, and hard. The earth at the
bottom must also be left smooth,
clear of debris, and undisturbed.
However, there is no need to make the
side walls of the trench plumb. The
only requirement is that the trench
be 30-45 centimeters wider than the
footing will be, so that the:e will
be room in the trench for the wooden
forms and work space for the builders.
A FINAL NOTE ON DIGGING TRENCHES
When digging the trenches, any loose
soil, or soil with organic material
should be shovelled
outstie
the
foundation lines and discarded.
Hard earth that is dug up should be
spread evenly &side the foundation
lines: it will be very useful as
part of the fill under the floor.
Organic E Loose Soil
129
Formwork for Footings
The formwork should be made of boards measuring about
5cm x 15cm
or
5cm x 30cm.
The boards should be supported by
5cm x lOcm
braces called studs. Allow about twice the width of the footing
between the studs (but never more than 1.3 - 1.6 meters); the
formwork must be strong because concrete weighs 2.5 metric tons
per cubic meter.
Tight Joints
to Prevent Leaks
In addition:
*
the joints and corners of the formwork must be tight: neither
the concrete, nor the water should be able to leak out. If
water leaks out it will weaken the mixture;
e
the walls of the forms must be exactly plumb (straight up and
down), and the tops of the forms must be level: any
inaccuracies will weaken the foundation;
. small boards, called spacers, should
be
nailed to the tops
of the formwork to keep the sides of the forms from leaning
toward each other before the concrete is poured;
. the formwork should be built so that it may be removed easily
without damage: most forms can be re-used;
l
if part of the footing will be visible and the builder would
like its surface to be smooth, the boards of the formwork
must also be smooth: .any irregularities in the wood
bends, chips, and so on - - burrs,
will leave an impression in the
concrete,
130
FORMWORK FOR A STEPPED FOUNDATION
The formwork for a stepped foundation
is constructed in the same manner
described above. However, if the
walls will be made of block or brick,
the height of each step of the
footing must be equal to the
height of the blocks used, or to a
whole number multiple of their
height. For example, if the blocks
used in the foundation are 20cm high,
then the steps must be 20cm or 40cm
or 60cm high, and so on.
Making the Concrete for Foundatisn Footings
To prepare a strong, durable concrete mixture# the builder must:
. select, prepare, and store the ingredients (cement,
sand, gravel) properly;
. use proportions of these ingredients that are
suitable for his or her purpose;
l
mix the ingredients properly with each other and with
water.
SELECTING INGREDIENTS
Cement
The commercial cement most commonly used for l-story buildings is
Portland cement. It is available from most manufacturers.
Portland cement, and most locally made limestone cements, can
be stored for up to 6 months in a cool, shaded,*, area. If the
cement has hard lumps that are difficult to break or crumble,
don:t use it.
In humid tropical areas, or areas with heavy rainfall, it
may
be
advisable to purchase "hydrophobic" cement, since this kind of
cement can be stored in damp conditions for long periods of time.
131
Sand
The sand is possibly the most
important ingredient in the
concrete mix, since it provides most
of the plasticity: that is, it makes
the mixture easy to work with.
There should never be more than 3
parts sand for every 1 part cement.
TOO ZittZe sand in a mixture may result
in shrinkage cracks when the concrete
dries; too
much
sand will produce a
harsh mortar that will be difficult
to work with and may lead to leaks.
Never use sand from the ocean: the
grains in ocean sand are too uniform
in size and will not make a useful
concrete. Any other source of sand
is fine. But it is crucial that the
sand used be clean.
To test whether sand is clean enough
to be -used:
. put 5cm of sand in a jar and
WATE R
fill the jar with water:
SAND b
. shake the jar vigorously for
1 minute and let it stand for
1 hour. The layer of dirt that
settles on top of the sand
should be less than 6mm thick.
If it is more, wash the sand or
find other sand (but again, do
not use ocean sand).
SAND: SHOULD BE LESS
THAN
6
mm THICK
Gravel
Gravel adds strength to concrete because it increases the range of
grain sixes in the mixture. Generally it is also the easiest
ingredient to find and prepare locally.
Gravel should be clean, and should range in size from 6-18mm.
247-201 0 - 71 - 10
132
MIXING THE BEST PROPORTIONS OF INGREDIENTS
The concrete mixture required for a foundation footing may be
very different from the mixture needed for concrete used for
another purpose.
For example, the average mixture for foundation footings is
1:2 3/4: 4 (that is, 1 part cement, 2 3/4 parts sand, and 4
parts gravel).
But a typical mixture for fence posts is l:l:l&. The higher
proportions of sand and gravel in the footing mixture provide
maximum strength and resistance to water. Since fence posts
do not need to be as strong or as water resistant as footings,
they can be made of a weaker and less expensive mixture.
Table 4 in Appendix 5 recommends average mixtures for different
uses of concrete. Following these recommendations will assure
builders that their concrete will be
M3CXIBTG PROCEDURE
Mixing Area
Concrete should be mixed on a flat
surface that will not absorb water.
Mix it on a wooden platform about
2 meters by 2 meters. Or, mix it
on a cement-sand platform.
Cement-sand platforms must be made
a week before concrete can be mixed
on them. To build a platform, mix
cement and sand on the ground in a
1:6 ratio, cement to 'sand. Add
water, and spread the mixture in a
circle about 2 meters in diameter.
well-suited to their needs.
133
Choosing A Measuring Unit
Since the dry ingredients ‘of concrete,
cement, sand, and gravel, are mixed by
volume, the easiest way to be sure
that the proportions are right is to
decide on a standard measuring unit
such as a box or wheelbarrow.
Once the unit is chosen, simply fill
it to the appropriate level with each
ingredient in turn. For example, to
make the recommended mix for
foundation footings, 1:2 3/4; 4, for
each unit of cement, add 2 3/4 units
of sand, and 4 units of gravel.
Generally, the easiest measuringunit
to use is a gauge box or wheelbarrow
that holds 1 bag of cement. The box
or wheelbarrow should be approximately
40cm x 4(?cm x 40cm. Note: to avoid
confusion, once the size of the
measuring unit has been chosen, do
not use different size boxes or
wheelbarrows on the site for any
purpose.
GAUGE BOX
When using a box:
. the box should have handles
on both sides for easy lifting
by two people;
. if the materials are close
enough to the platform so that
they do not have to be carried,
it is easier to use a bottomless
box: set the box directly on the
mixing platform and fill it to
measure; then, lift it up to
empty the ingredients into the
mixture.
Mixing the Ingredients
The ingredients in concrete should
always be mixed in the same order:
FIRST,
spread the correct amount of
sand on the platform with a shovel.
SECOND,
dump the required amount of
cement on the sand, and mix the
sand and cement until the color of
the pile is uniform: there should
be no streaks of color.
THIRD,
add the required amount of
gravel and mix it with the sand
and cement until the gravel is
thoroughly distributed and there
are no streaks of color.
FOURTH,
hollow out a hole in the
center of the.mix. Add water
slowly, pushing the ingredients
toward the center while turning
them over with a shovel.
4
4
135
A good test for the correct amount
of water is to walk on the mixture:
a if you sink to your ankles or
higher, there is too much water;
a if you sink about 5-6cm, you
have the right mixture.
The correct amount of water is
important because too much or too
little will weaken the mixture:
CORRECT AMOUNT OF WATER
- if there is too little water,
air spaces (weak spots) will form
in the concrete;
- if there is too much water: a
cement-water paste will rise to
the surface, weakening the
mixture underneath.
Pouring Concrete for Foundation Footings
Fresh concrete mix has to be
carried to the footing trench in
water-tight containers such as
wheelbarrows: no water should
seep out of the mixture:
l
the mix sh.Duld be poured
within 45 minutes-of
mixing;
0
avoid b:;mps during transport
from the mixing area to the
site: vibration will cause
the aggregates (sand and
gravel) to separate from
the mixture;
l
it is best to let the mix
flow into the trench; do not
drop it into place or the
sand and gravel may begin separating from the mixture;
. once in place,
a shovel, rod, the concrete should be worked up and down with
or spading tool to break air pockets;
. footings up to
30cm
deep can be poured all at once; deeper
footings should be poured in layers
15-30cm
deep at a time;
l
once started, the pouring must be continuous: concrete that
has started to set crmnot be disturbed;
if you must stop pouring at the end of a day, place a vertical
stop at the end of the poured section;
when pouring is resumed, roughen the edge of the old section
and paint it with a cement-water paste before applying fresh
concrete. (Use a stick or any sharp object to roughen the
old section).
l
Curing Concrete Footings
As concrete hardens, the water in the mix gradually evaporates.
Prolonging that process increases the strength and water-
tightness of concrete.
Immediately after the concrete has set , put a wet covering over
The covering may be made with wet burlap bags, or a thin
layer of wet sand, or uet straw. The covering should be
sprinkled with water 2 or 3 times a day for at least 7 days.
.I.
Reinforced Footings
Reinforced concrete footings require the same formwork as
unreinforced footings (see page 129). Steel rods are attached to
the form before pouring. The rods should be made of steel about
9mm in diameter. They must be cleat ---= free of rust.
When placing the rods:
. 'Jse steel wire to hold them in place 2.5-5cm above the bottom
of the trench, and 5-7.5cm from the sides of the forms.
Temporary wood supports may be used while the steel wire is
being tied in place,'
concrete. but they must be removed before pouring
Plain round bars must be hooked at the ends; deformed bars
' (bars with curved ridqes along their surface) can be left
will hold the concrete firmly.
straight
since their ridges
. The ends of bars should be
spliced (overlapped) for a
length
at Zeast
30times the
diameter of the rods. For
example, 9mm rods should
overlap for 2.7 meters.
PLAIN ROUNP DAc
e The rods must be complett_ly
surrounded by concrete, and
the concrete and steel must
be fuZZy and
tightly
bonded
to work properly; any
exposed steel will rust
through, and this will
weaken the steel and
destroy the bond.
“DEFORMED” BAR
The recommended concrete mixture for reinforced foundation
footings is 1:2&:4.
Footings may also be reinforced with bamboo. See the separate
section on Bamboo, page 188.
CONSTFBUCTION OF THE FOUNDATION WALLS
.Once the foundation footing.is complete, construction of the
foundation walls can begin. The foundation walls may be made of
concrete, or anyofthe blocks made with cement (Sand-Cement,
Stabilized Earth). Adobe blocks should never be used for a
foundation.
The foundation walls should be built so that the top of the
foundation is exactly level with the floor height (at least
lo-30cm above the ground at the highest point on the building
site).
Concrete Fowndation Wafls
MIXTURE
The best concrete mixture for foundation walls has the same
proportions as the concrete for footings: 1:2 3/4 :4.
FORMWORX
The best formwork to use for concrete foundation walls isre-usable
unit formwork. Since each "unit" can be used over and over again,
the cost of the wood for the formwork can be shared by an entire
community.
If possible, it is best to complete all the foundation walls in
one day's pouring: this will avoid
seams
in the concrete.
If it is necessary to stop before completion of the walls, the top
surface of the last layer poured should be roughened by scratching
it with a stick or placing large pebbles that project out of the
surface. This will provide a good "grip" for the fresh concrete
when the pouring resumes.
CURING
In warm weather, the forms can be removed after 3 days; in cold
weather, leave them on at least a week and preferably 10 days.
As with footings, cover the surfaces of all concrete foundation
walls for at least a week with wet sand, straw, or burlap.
Block Founciation Walls
Construction of a block foundation wall requires 3 basic steps:
a Making the blocks:
. Laying the blocks;
. Finishing the Mortar.
Making Blocks
There are three types of block suitable for foundation walls:
concrete blocks, sand-cement blocks, and stabilized earth blocks
lnot adobe).
Each-requires different procedures and ingredients.
MAKING CONCRETE BLOCKS
A
Ingredients
The ingredients required for
concrete blocks are cement, sand,
and gravel in a 1:2:4 mix. The
concrete is mixed using the method
described on page .132-136.
Forms
The most commonnomina2 size of
concrete blocks is 20cm x 20cm x 40cm.
141
The nominal size of a block is the
acttta2
size of the block + the
thickness of mortar in which it will be set. Planning for 5mm cf
mortar between blocks, this means the actual size of the most
common concrete block is'19.5cm x 19.5cm x 39.5cm. Thus, the
forms used for these blocks should measure 19.5cm x 19.5cm x 39.5cm
on the inside.
The forms should be made of wood 2.5cm thick, with removable cores
(or dowels) to create holes in the block.
Procedure
The mixture should have enough water to make the mix plastic but
not watery. The mix is placed in the form and hand-spaded or
vibrated mechanically to remove air pockets.
If the mix is spaded, the forms should not be removed for at least
12 hours (or 2-3 days in cold weather). If the mix is vibrated
mechanically, the forms may be removed 30 seconds after vibration.
The cores should be removed first: tap them gently and pull them
out slowly. Then slowly remove the outside form. Avoid breaking
the corners and edges.
The blocks should be kept damp for 7-10 days and should be
sheltered from wind and sun for 28 days before use.
MAKING SAND-CEMENT BLOCKS
Inaredients
The usual mixture of cement-to-sand
'for sand-cement blocks is 1:6. A
mixture of 1:8 can be used for block
walls that will not carry roof loads,
but this is
not
sufficient for
foundation walls.
The best sand is clean river-bed
sand composed of many different size
particles. If it is dirty, the sand
should be washed, or sifted through
a fine screen (4-5mm square), since
dirt will weaken the blocks. Do not
use ocean sand.
M_ixing Site
The site for making sand-cement blocks should be flat and shaded:
if the blocks rest on an une-ven surface, they will crack before
they harden; and direct sun will dry blocks out before they can
cure properly. If the mixing site
mustbe
in the open sun, the
blocks should
be
moved to a flat, shaded area for curing.
142
Mixing
Following the mixing procedure for concrete (page 132),
measure out the proportion of sand and then mix the cement in
thoroughly. AddcZearlwater in the center of the pile and turn the
ingredients over at least 3 times until all streaks disappear and
the mixture is even. The mix should have the consistency of
concrete: wet, but not watery.
Moldina Sand-Cement Blocks
Sand-cement blocks may be molded by
hand or with a simple hand-press.
Blocks made by press are generally
stronger and more durable. But
blocks made by either method are
acceptable.
Hand Molding. If a commercially made
mold 1s not available,
a
mold? can be
made out of 2.5-5cm lumber in the
dimensions desired. Typically, these
blocks are:
ACTUAL SIZE, cm NObUNAL SIZE, cm
19.5 x 19.5 x 39.5 20 x 20 x 40
14.5 x 19.5 x 29.5 15 x 20 x 30
9.5 x 19.5 x 29.5 10 x 20 x 30
Once the molds of the correct size
have been built, shovel the wet
mixture into the mold and shake the
mold to settle the contents.
Then re-fill the mold slightly over
the top and pack the mixture down
with a spade or shovel. Scrape any
excess off after packing thoroughly.
143
Next, carry the full mold to the curing area.
Turn it upside down gently,
from any previous blocks. and place it a few centimeters away
Then, lift the mold off: first the core;
then, the casing.
made. Repeat the process until enough blocks have been
Using several molds simultaneously will greatly speed the
process.
144
Molding With A Hand Press. There
are several types of has press
available for making strong sand-
cement blocks. Cinva-Ram and
Tek-Block presses are the most
common, but any similar press will
work as well.
There are three basic steps in the
operation of most hand presses:
0 loading the mold box;
. compressing the mix;
l
ejecting the block.
With any hand press, it is a good
idea to make a few test blocks
before starting production in
order to determine the correct
amount of mix needed to make a
strong block.
i45
D
Curing Sand-Cement Blocks
Sii. --cement blocks should be sprinkled with water after they have
set for about
12
hours. They should be dampened at least once a
day for 5 days. They should not be laid up in a wall for at least
12 days after being molded.
MAKING STABITIZED EARTH BLOCKS
Ingredients and Soil Selection
The selection of a suitable soil
for mixture with cement is crucial
in making strong stabilized earth
blocks.
There
are,
roughly, 5 kinds of soil:
. gravel
- rock ranging from 5mm
to 7.5cm;
l sand
- rock particles 5mm and
smaller;
l silt
- very finely ground rock,
spongy when wet, but not sticky:
l czQy
- very fine grained earth,
sticky when wet, hard when dry;
a orgcmic soils - spongy, stringy
appearance, odor of decaying, wet
wood.
The best natural soil for stabilized
earth blocks is sandy clay. As with
plain concrete, ,the strongest blocks
have a combination of fine, medium,
and coarse particles. Earth that has
only one particle size, or has
mostly
organic and/or coarse particles is
unacceptable.
STABILIZED EARTH B;OCK FORM
146
Testing Soil Acceptability
To determine whether local soil can
be
used to make stabilized earth
blocks, use the following test,
called the "jar test":
l
Fill a glass jar about l/3
full of soil.
. Add water to the 2/3 mark.
Shake vigorously for 11. minute.
: Let the jar set for an hour.
When the soil has settled
there should be 3-4 distinct
layers in the jar. If there
are not, reject the soil.
/VEGETABLE HATTER
A VERY FINE
1 FINE
v COARSE
Deciding How Much Cement to Mix With the Soil
Once
much
This
an acceptable soil has been found, you need to determine how
cement to mix with it to make strong stabilized earth blocks.
can be done easily with a "shrinkage test":
Make a box 4cm deep,
4cm
wide, and
6Ocm
long.
Grease or oil the insides thoroughly.
Fill the box with damp, but not muddy, soil.
Pack the soil with a shovel. or spade, especially at the corners.
Level the surface with a str,aight edge or ruler.
Place the box in the sun for 3 days, or in the shade for 7 days,
and protect it from rain,
The soil should shrink .and develop
3 or 4 cracks.
IT 6 o~more cracks
appear, or Zf the dried sdZ arches out of
the box, reject the soil. It will not make
good blocks.
As long as there are
less than 6 cracks and the soil lies
flat in the box, measure the shrink-
age .by tapping the box and sliding
the soil to one .end:
If the shrinkage is: use a cement: soi 1
ratio of: -
lcm or less l-15
lcm to 2cm
2cm to 4cm
4cm
to
5cm
more than 5cm
1-12
l-10
I- 9
reject the soil, or
add sand and repeat
the test
147
Mixing the Ingredients
Once a sui table soil has been
selected, it should be screened
through a wire mesh with holes no
larger than 5mm.
After the soil has been screened,
measure out the proportions of
earth, cement, and any sand to be
added.
On a platform or other flat area,
mix the ingredients thoroughly as
for concrete.
Add water slowly with a watering
can until the mixture is moist but
not muddy.
B
To test whether you have added the
correct amount of water, squeeze a
handful of the wet mix into a ball:
l
If it can be broken in two
without crumbling and without
leaving moisture in the hand,
the amount of water is correct;
l
If the mixture crumbles, it is
too dry. Add more water and
repeat the test.
l
If the mixture leaves moisture
in your hand, it is too wet.
Compress the mixture and
allow
the excess water to run off.
It is best to test the mixture
frequently to avoid getting it
too wet.
n
_-.
-
148
Curing Stabilized Earth Blocks
The moisture in stabilized earth blocks should be eliminated
slowly, under cover, with the blocks protected from sun and rain.
For the first 3-4 days the blocks should be separated in single
rows, never stacked upon each other. They should
be
sprinkled
lightly with water twice a day for this initial period. After 4
days r the blocks
may
be stacked up to 10 layers high in a pyramid
fashion with a little space between each brick. On the 8th day,
bricks
may
be laid up in a wall where they will continue to cure
and gain full strength in about 30 days.
laying Block Foundations
When the footing has been poured and
has cured for about
a
week, and the
SECOND COURSE
blocks have been made, construction
of the foundation wall can begin.
All block foundation walls, whether
concrete, sand-cement, or stabilized
earth, are laid the same way.
First, stack a number of blocks at
intervals along each
wall
line so
that
a szqply is always at
hand.
FI RST COURSE
Next, lay out the planned number of
blocks for the first row (course) on
or alongside the footing and check to
see'how well they fit the length of
the wall. Very small adjustments in
the length of a wall (under
7.5cm
over the length of the whole wall)
may be made by increasing the size
of mortar joints between every 5th or
6th block. For example, if 8 joints
are made lcm instead'of &cm, the wall
length will be increased
4cm
without
cutting any blocks.
To give the wall strength, the courses
(rows of blocks) must be staggered so
that the bond between any two blocks
rests over the middle of the block
beneath them.
STAGGERED BOND
To stagger the courses, turn one
corner block on the first course so
its "head" faces out. Then, on the
next course, turn the block at the
opposite corner head out.
Continue alternating between courses
in this way.
I
I
149
To ensure that the blocks are laid
in a straight line, run a string
from corner to corner along each
wall. For outside walls, attach the
string to the batter boards; for
inside walls, attach it to a nail
hammered between two courses of
blocks.
If the string sags, as it is likely
to do over a distance, support it [
with a piece of paper that is
BATT,,,
weighted with a small rock.
BOARDS L
1
PAPER WE I GHTE 0”;;
Use the string as a guide, laying
each block
up to but not touching thz
STRiNG j
w-c. .-.z
line.
The string can be moved up
later for each new course of blocks. -:-t
. .
Once the string is in place for the F
first course, you are ready to
prepare the mortar.
The recommended mix for mortar to
lay blccks is 1:3, 1 part cement to
3 parts sand. Mix these ingredients
with each other and with water as
concrete is mixed (see page 132).
During the dry season, it helps to
sprinkle the blocks with water
before they are laid in mortar.
This prevents them from absorbing too
much water from the mortar.
To lay the first course of blocks,
use a trowel to spread out a full
bed of mortar about 1.25cm thick on
the footing. To prevent the mortar
from drying out before blocks are
laid in it, spread only enough for
4 or 5 blocks at a time.
Using the batter board lines as
guides, position the first block -
the corner block -
very carefuZZy:
an
error here will cause problems that
are hard to correct.
When the corner block is positioned.,
tap it down firmly - do not pound -
until it is solidly bedded in the
mortar.
150
Butter the ends of each new
block to bond the vertical joints
between blocks. Press each new
block against the previous one until
a solid mortar joint about
15cm
wide
is formed.
Keep trowelling of the bed to a
minimum: it will draw water out of
the mortar
mix,
weakening the bonds.
Any excess mortar that squeezes out
between blocks should be scraped off.
It can be re-used if it has not dried
out. Once mortar dries out it must
be discarded.
After every
3
or
4
blocks are laid,
check the course with a level. if
it is not level, remove the blocks.
add mortar, and lay them again.
Once the entire first course of
blocks is down, build up the corners
at least 4 or 5 courses up, or all
the way to the top. This will give
you something to attach the guide
STORY POLE Bw
string to for the upper courses.
Use a story pole to check the height
of each course, and to check that
all corners are going up evenly.
CHECKING LEVEL
FIRST
152
THIRD, pour the concrete.
Use the procedure for pouring concrete
footings without forms as a guide for this step (pages 127 and
1351. Use a concrete mix of 1:2 3/4 :4. Let the concrete cure
for 2 to 3 days.
FOURTH, Zuy the rocks.
Tie a string to the batter boards as a guide
for laying the rocks. Use a mortar mix of 1 part cement to 3
parts sand. Spread a mortar bed about 1.25-2.0cm thick on top of
the concrete base. Bosition the rocks and tap them into place
as if they were blocks.
Mortar all the joints between the
rocks; the outside surfaces of the
walls don't have to be flush, but
the joints should be compact.
. Be certain to lap all the joints
(that is, stagger the rocks) to
prevent a straight-line crack
from developing.
.
If possible, alternate the
direction of the "corner" rocks.
Finish the exterior mortar joints
in the wall with a jointer to
strengthen the joints and help
waterproof the mortar.
Keep the top surface of the rock
foundation wall as level as
possible.
153
r
CONSTRiJCTION OF FLOORS
After the foundation walls are complete, but before starting the
regular walls, a floor should be started, level with the top of
the foundation walls.
Earth Floors
Earth floors are easy to build.
For drainage, simply place a
layer of dry fill inside the
area bounded by the foundation.
The fill can be made of any
material that will not hold
water, such as gravel, rock,
broken brick, or rubble. The
top of the dry fill layer
should be about 5cm below the
top of the foundation walls.
The fill will be packed down
as people walk over it during
the rest of the construction
process.
When the walls are complete,
add a
lo-15cm
deep layer of
hard earth and pack it down
either with a shovel, or by
walking on it. When the
hard earth is well-packed',
wet it down slightly, and
sweep it out to complete the
floor.,
)HARD PACKED EARTH
_-
Foundation Wall)
Concrete Floors
FILL
Like earth floorsp concrete floors need a level of dry fill
underneath for protection against ground moisture. Dump the
fill inside the foundation walls so that it will be packed
down by rain and people walking over it during construction
of the walls. The fill should be composed of two layers:
a bottom layer of dry fill: rock, gravel, broken brick, or
rubble; and a top layer of hard earth. If dampness in the area
is excessive, a 5-7 cm. layer of sand with a sheet of plastic
(or other waterproof material on top) should be laid between
the dry fill and hard earth.
f
CONCRETE
/ PACKED EARTH
Ilf
SAND (DPTHINAL)
a
The top of the hard earth should be about 10 cm. below the top
of the foundation walls.
PREPARING TO POUR THE CONCRETE
Concrete floors can be poured at two stages in the construction
process:
l
after the foundation wails are complete, but before the walls
are put up;
l
after the walls have been put up.
There is an advantage to the second alternative: since the floor
and walls will very likely settle at different rates, the floor
may develop cracks if it is connected to the walls. Another
advantage is that the walls and doors provide easy protection for
the floor while it is curing.
if the fill has been in place some
time, check that the hard ear,th is
at the correct level--about 10 cm.
below the top of the foundation
walls. If it has settled, add
more hard earth and pack it down
hard. Wet it and then pound it
with the end of a steel rod.
Use a straight edge and a level. to
check that the surface is
reasonably level before the concrete
is poured.
Pound 6 or 8 wood stakes (about
5 x 10 cm.) into the fill so that
their tops will be even with the level
of the finished floor (the same
as the top of the foundation
walls). These stakes will guide
you during the pouring, but they
must be removed
before the concrete
settles.
POURING THE CONCRETE
The best concrete mixture for floors is a 1:29:3 mixture (1 part
cement:24 parts sand:3 parts gravel). Mix the cement as
described on pages 132-135.
Then, begin pouring in the corner
farthest
frbm where you will finish
and work back toward a door so you can
on the fresh concrete. get out without walking
Pour the concrete at the full thickness--
10 cm --don't layer it.
156
As the area covered grows, begin
to level the concrete off with a
"screed"-- a board about 5 x 10 cm
and several feet long that is
swept across the surface to keep
the mix even with the tops of the
guide-stakes.
Then, before the concrete sets:
1. remove the guide-stakes and
fill their holes with concrete,
2. tap any pieces of gravel
and rock that stick out
above the surface into the
concrete and smooth the
surface over.
Using thin boards to kneel on or
walk across the surface without
marring the fresh concrete, . .
"finish" the floor by sweeping a
trowel or wooden "float" across
the surface. A rectangular
float is best--approximately
.15 x -25 cm. The sweeping
action will bring a smooth
cement-water paste to the
surface of the floor. Be
careful not to bring up too much
water: if water collects in small
pools, the surface of the
concrete will be too weak when
dry.
After the floor has started to
harden, but while it is still
workable, sweep the surface with
a broom. This will give a rough
texture to the finished floor and
create a safe, non-slip, surface.
When the floor is finished and is
left to cure, close the, doors and
windows to keep children and animals
from walking on the surface.
The floor should cure for at least
4 days, and preferably 10. Keep the
surface moist by sprinkling frequently.
Since so much area is exposed, the
concrete can easily dry out too
quickly.
157
CONSTRUCTION OF WALLS, M!!MDOWS AND DOORS
-a.m.,
Once the foundation walls are complete, construction of the walls,
windows, and doors can begin. This part of the manual covers
two kinds of wall construction:
- Block or Brick Walls, and
- Rammed Earth Walls.
BLOCK AND BRICK WALLS
Making the Blocks or Bricks
BLOCKS WITH CEMENT CONTENT
The procedure for making concrete, sand-cement, and stabilized
earth blocks is discussed earlier on pages 140-148. For walls made
of these materials, build a mold for blocks f the length of a
full-size block: the f-length bloc.ks will make the framing
of windows and doors considerably easier (see below).
ADOBE BRICKS
Adobe bricks are made from clay and sand. Where available, silt
(very fine particle material) will increase the range of particle
sizes and strengthen the mixture.
The proportions of these materials can vary considerably. But
a good mixture to begin with would include:
0 6 parts sand,
0 24 parts clay,
l
13 parts silt.
Adding straw or chopped grass will always strengthen the bricks.
Make some test bricks and then adjust the proportions as necessary.
Some things to keep in mind while experimenting with different
proportions:
- silt should never be more than 15% of the mixture;
- A healthy amount of sand is necessary to keep the clay
from shrinking. On the other hand, too much sand makes
the mixture watery and weakens the bricks as they dry.
158
Mixing Materials.
Use a mixing platform as for mortar or concrete (page 132).
Measure out and mix the proportions and add water slowly: if the
mud is too wet it will slump gradually while it dries outside
the mold. No large stones or lumps can be left in the mixture,
but stones up to 1.5 cm are all right.
Molds.
The most common adobe brick has anom&zuZ size of 10 x 15 x 30 cm.
it is made with a bottomless mold with
amha2
inside
dimensions
of
9 x 14 x 29
cm.
Use hard wood for the mold.* It may be easier, after some experience,
to line the mold with a strip of sheet metal. -__
Molds for several
bricks at a time are easy to make and increase the efficiency of
brick production.
Like blocks with cement
content, adobe bricks cannot
be broken neatly into halves
or quarters. So, for framing
windows and door jambs, it's
best to make a half-length
mold as well as several
regular molds (see window fram-
ing below, page
162).
D
390; Png Adobe Bricks.
Bricks can be made on flat, level ground, but using a table is
often faster and easier.
Place a clean mold (dipped in water) near the edge of the
table.
Fill it with mlud, being sure
like mortar, to pack the corners. The mud,
should be workable but not sloppy.
Clear any excess mud off the mold, but don't make the surface
too smooth-- the brick will adhere to the mortar better if it
has a rough contour,
Slide the mold briskly off the edge of the table and carry
it in a vertical position to the drying site.
I
WATER BARREL
I
I
Gently place the mold on
C?m$
ground,
J
close to the
last brick made. Let it sit
for a few moments, then lift
the mold up slowly.
Rinse the mold off thoroughly
(in a barrel of water)
before making another brick
with it.
160
Curing
Bricks must be dry before they can be used; if they dry in the
wall they will shrink and ruin the mortar bonds. The bricks
should dry in the sun for about 30 days. For the first week or
SOf the bricks should be protected from rain. Sheet metal
provides a good protective cover. After the first week they
can be safely exposed to light rainfall.
Turn each brick over every 5 or 6 days to assure even drying.
A Note on Mortar
Adobe bricks are generally laid with mortar made from thesame
mix as the bricks.
Laying Blocks and Bricks
The basic laying procedure for block and brick walls is the same
for all types of block and brick and is identical to the procedure
for .block foundation walls (see pages 148-151).
0
The top surface of the foundation, or of the previous course,
should be covered with a bed of mortar.
on the edges of hollow bricks. Apply the mortar only
Cover the entire surface of
solid blocks.
. Butter each new block or brick on its ends either before or
after it is placed. Again, butter only the edges of hollow
blocks; butter the entire head of solid blocks.
‘ORE
161
. Use string to guide the
placement of each new block or L
brick in a straight line.
Position the blocks or bricks
BUT NOT -
up to but not touchhg the string.
TOUCHIN-
Press and tape each one firmly
zz:z:?
into place so that the mortar
@.&j
.pyf
:-'::;:.:,
joint is l-1.25cm thick. Do
not pound the block in place. :::
..,
a
After every 2-3 blocks or bricks
check the course for level and &~~
.a:::.+:.. -.-. . _.... . . .
plumb. . . . ..&..~.~.-.L.: .:,. :::.::,::..-.'...:..~..-..,..~~...
Remove and re-mortar any . . . . . . . .
. . . . . . . . . . . . ..>...'..... :::z ..,.,..,
blocks that are out of iine.
HOND ARRANGEMENTS FOR BLOCK AND BRICK WALLS
There are important differences between the bonds that should be
used with blocks and the bonds for adobe bricks.
Bonds for
BLOCKS
With Cement Content
The main bond for blocks with cement content is the staggered
arrangement used in block foundation walls. This simple bond is
easily continued through corners by alternating the direction of
each corner block ( see page 148 for details).
When working with blocks, the
intersection of exterior and
interior walls is treated
much like a corner.
164
Framing Windows and Boors
Windows and doors in block and brick walls must be planned so
their heights are coordinated with the size of the block or brick
used (see pages 95-96).
All windows and doors consist of 3 basic parts: the head, the
sill, and the jamb. In addition, there must be a lintel above the
opening to support the blocks or bricks over the open space.
FRAMING WINDOWS AND DOORS IN BLOCK WALLS
In block walls, the lintels should be made
of reinforced concrete.. There sh,-Td also ----a-
be a concrete sill about 7cm thick under
the wood s.ill of the frame.
Frames (heads, jambs, and sills) should be
wood, usually 2.5cm x 15cm hardwood lumber
in block walls. WOOI
To build the space for a window or door in
a block wall, follow these steps: e?
...
Lintel
JAM6
I.
9
:
CONCRETE
SILL
1. Make a mold for the reinforced
concrete lintel. The mold should
be as wide as the wall, as deep as
the height of 1 block, and 13 times
as long as the window or door is
wide.
2.
Fix 2 reinforcement rods in
the mold and pour a 1:2:4 concrete
mixture. Remove the mold and cure
the lintel as you would a concrete
footing (see page 136).
FRAME FOR LINTEL
b
B
The Sill
3. Make a mold for the concrete sill.
The mold should be as wide as the wall,
about
7cm
deep, and as long as the window
or door is wide. Then, pour a 1:2:4
concrete mixture and cure it just as the
lintel was cured.
4. Prepare the surface of the wall where
the sill will be placed by spreading a bed
of mortar on the blocks.
5. Put the sill in place and press it
down firmly until the mortar joint is the
same
thickness as the joints between
courses.
6. Immediately check for level and adjust,
if necessary, by forcing one end down. If
the sill is not level after this, take it
off, add mortar, and repeat.
TEMPORARY
BRACE 1
The Frame (2.5cm x
15cm
hardwood)
7. Place the wooden frame on the concrete
sill and hold it in position with
temporary braces.
8. Continue laying blocks on either side
of the window: the wall must go up evenly
on both sides or it will
qo out
of plumb.
9. Attach the frame to the wall with
mortar and with nails hammered into the
masonry.
165
10. At the top of the opening, lay the
pre-cast lintel like a block:
l
if the walls are more than
75cm
thick, allow a few hours for the
courses
below
to harden before
placing the lintel:
l
apply mortar to the blocks or
bricks at both ends of the lintel
and adjust for the same joint
thickness;
. check for level and adjust.
FRAMING WINDOWS AND DOORS IN ADOBE BRICK WALLS
Adobe brick walls require wood
lintels and sills that serve as the
head and base of the frame.
The easiest method is to make the
lintel and sill equal to the height
of the brick used (usually
10cm) so
you do not have to cut or make bricks
in half-heights.
When the wall reaches window height -
or at floor level for a door - place
the frame in position on a bed of
mortar and support it with braces.
The jambs of the frame should be
5cm
thick..
Check for level.
Lay the next course or two of bricks
and check again for level and plumb.
-T-
MULL I ON >
At this point, the wall on
_ .
each side of the frame will exert enough pressure to keep it in
position.
Before laying bricks over the lintel, support the lintel with a
temporary 5cm x 1Ocm or
1Ocm
x
1Ocm
post, called a mullion. The
mulIion should remain in place until construction of the wall is
complete,
Roof Preparation
Near the top of the wall, preparations must be made for
attaching, and providing support for, the roof.
There are two basic kinds of preparation: wall plates and ring
beams. They are built and used in the same way on all block
and brick walls.
WALL PLATES
Wall plates are solid,
continuous
wood
beams (usually
5cm x 15cmj that connect the
exterior walls of a building
along their tops and anchor
the roof to the walls. They
are essential in all buildings
except bamboo structures.
The wall plate can be held in
place with 3 devices:
a a good mortar bed; as thick
as the horizontal joints in
the rest of the structure:
. steel straps (bale iron wire)
anchored l-3 courses below
the top of the wall (at
least 20cm); place the
straps in the appropriate
mortar joint every 3-l meter;
. bolts anchored l-2 blocks or
bricks below the top of the
wall every 2 meters:
-with small bricks, the
bolts can be anchored with
a thin metal plate (called a
167
b
BALE IRON
retainer plate) between mortar
joints;
-with hollow blocks of whatever size, the bolts can be placed
in a core and the core filled with concrete (1:2:4 mix).
Corner joints of the wall plate may be fastened either with lap
joints or batten joints. Battens are slightly stronger.
BATTEN JOINT
WITH BALE IRON STRAPS LAP JOINT
WITH BOLTS
RING BEAMS (ALSO CALLED THE BEAMS)
A ring beam is a continuous
reinforced concrete beam poured in
place at the top of
concrate block
l&.ztts only.
Ring beams help the walls resist
the outward-spreading pressure from
the roof, provide extra
reinforcement in earthquake areas,
and provide a solid base on which
to attach the wall plate.
RCEMENT RODS RCEMENT RODS
ST ST COURSE OF %L COURSE OF %L
4
REINFORCEMENT BARS
4
.OCK
Ring beams are poured in place, so
formwork must be attached to the
sides of the walls already up.
The beam should be about 15cm deep
and exactly as wide as the wall.
It should also be reinforced with
2 steel rods l-l&cm in diameter.
Follow the guidelines for concrete
formwork on page.129 and use a
1:2:4 mixture.
To avoid any seams, ring
beams must
be
poured
in
one
continuous
operation.
RAMMED EARTH WALLS
169
Rammed earth walls are built in layers by packing a damp earth
mixture into temporary forms, allowing each layer to dry slightly,
and then moving the forms to repeat the process until the walls
are as lligh as planned-..
Earth Mix-ture
The earth used should be basically the same mixture used for adobe
bricks (page 157). However, the proportions of ingredients are not ES
critical. Large amounts of straw added to the mixture will
increase the strength of rammed earth walls significantly.
Only a little water should be added to theearth until it is firm
and damp (not muddy).
If a suitable grade of earth can be found,
rainy
season), properly damp (after the
it can be brought directly to the building site and
used as-is, or with straw added.
Forms
The most manageable size for the
forms is 45cm deep by 2 meters
long and 37~.5-45cm wide,
depending on the wall thickness
planned.
The forms should be closed on 3
sides: the open side is placed
against the previous section of
wall. There can't be any
spreaders or supports inside the
form, so the form's strength comes
from battens on the outside held in
place with iron straps at the top
and flat iron bars at the bottom.
Two special forms should be built
for corner sections with alternate
long and short sides. The se
"corner" forms are held together
with interlocking iron pins in
addition to the strapped battens.
Rammed earth is not very easy to
mold or shape once in place, so
planning beforehand is essential.
First, mount the forwork on the
foundation wall, using-iron straps
or wire around the battens. Check
the form for level and plumb.
Place 1Ocm of earth in the form
and pack it down solidly with a
small rod about 4cm in diameter.
Use quick, short strokes. The
corners must be especially well-
packed.
As much as possible, avoid shaking
or vibrating the wall since this
tends to loosen the earth.
. I RON STRAP
III
FLAT I RON BAR
(TO StjPPORT MOLD)
L LONG SIDE
A
-
25ciii : RDN P-ii
- CORNER FORi4 DETAIL
Add more earth and ram it down until
there is a firmly packed layer 30cm
deep. Scrape lines about $cm deep
in the top suzfacs to give the
section some additional "grip".
4
171
Wait at least an hour before
removing the form and starting a
new section above the first.
If the earth on top of an old layer
has become dry, sprinkle it lightly
to dampen it before putting new
earth on top of it.
Overlap the corners by alternating
short and long legs. This will
greatly increase the strength of
the walls.
Rammed earth walls can be
reinforced. Run a steel band
around the entire building just
Rbove the door and window level. A
second band can be run just below
the roof if desired.
To guide the steel band around
corners, drive pegs about 20cm
long into the rammed earth before
removing the form.
Framing Windows and Doors
Windows and doors are framed
according to the same basic
procedure followed with adobe brick
walls (see pages 164-165). Use
wooden sills and lintels about
5cm
thick.
r'irst, place the sill in the proper
REVERSE MOLD FOR EACH COURSE
CE IN FORCEMENT
place and press it into the
top of the damp earth. Check for level.
Wext, place the frame, including the combination head-lintel on
the sill, and brace it.
Then place forms on either side of the frame and build the walls
up on both sides, checking the frame frequently for plumb.
Finally, before building above the lintel, support iz. with a
temporary brace.
172
Roof Preparation
To mount a wood wall plate on the
top of a rammed earth wall, place
steel rods in the wall about
3-l meter below the top of the
wall. Then wrap iron straps
around the wall plate and
fasten both ends of each strap
to the steel rods.
WA1
CONSTRUCTION OF ROOFS
It is a good idea to coat all wood and bamboo roof materials with
an anti-termite solution-such as carbonyl, Xylophene, or Creosote.
. .
In areas with very strong winds or storms, it may be advisable to
have an experienced local contractor check the roof plan.
Flat Roofs
To build a flat roof, simply follow
the steps below:
l
Place the beams across the top
of the walls every f-l meter and
lash them securely to the wall-
plate with iron straps or
staples. Avoid nails through
the beams since they may split
the wood.
. on
the ground, construct
the purlins out of
sections of
5cm x 1Ocm
wood. Purlin sections
should be spliced
together, as shown,
wtth
the Zonger piece over the
shorter piece.
Take care
that splices will not
be directly over a beam
once the purlin is in
place. Each completed
purlin should be lifted
into place and lashed
witn iron straps to each
beam.
0
Finally, the roof
covering should be
attached to the purlins.
Follow local custom when
using materials such as
thatch, mud, or tile.
Avoid corrugated
metal
for flat roofs: the
metal sheets make
buildings very
uncomfortable in hot
climates and tend to
rip off easily in wind.
Shed Roofs
CORRECT: Long piece is suppvrted by the short
piece
INCORRECT: Nails are not strong enough to
support the long piece
Simple, beam-supported shed roofs
for buildings where one wall is
built higher than the other-are
constructed according to the
same
procedure for flat roofs.
One Wall is Higher
174
For truss-supported shed roofs,
follow these steps:
STEP 1. Place beams across the
top of the walls as for flat
roofs. However, these beams may
be further apart, up to 1.3-i.4
meters, depending on the roof
covering to be used (closer for
heavier materials, further for
lighter materials). The beams
must be as long as the distance
between the two walls they will
rest on + the overhang planned
on each side.
STEP 2. On the ground, measure
and -mark off the outline of the
truss.
P
---- fiil
-;I-- 1
---- m---i
-=- 0 l4 0
------r,-- I
------I
STEP 4. Fasten the pieces of
the truss together, either by
bolting or nailing them.
Whether bolts or nails are used
as fasteners, the -joints may be
made either by overlapping
pieces; or,
by using single or double plates
(separate pieces of wood) to
hold the truss members together;
err
by splicing. When splicing, use
iron straps to reinforce the
joint fur-ther.
b
176
STEP
5.
Repeat steps 3 and 4 until a truss has been built for each
beam in the roof.
STEP 6. To position the trusses and attach purlins and roof
material, follow the instructions for gable roofs below.
4
Gable Roofs
To construct a gable roof,
follow the steps below:
STEP 1. With a tape measure,
mark off the outline of the truss
-- the di-stance from the rafters
to the tie beam, from the struts
to the tie beam, and so on -- on
the ground. Loosely organize the
pieces for the first .truss along
the lines marked and hammer
stakes in the ground to hold each
member in place.
STEP 2. Check the measurements
of the pieces on the ground
'against the plans and make any
needed adjustments; then make
sure the stakes are firmly in the
ground and won't move.
STEP 3. Assemble the truss with
permanent connections as for shed
roof trusses using the-
connections indicated on page 175.
STEP 4. As each truss is
assembled, put it up by pushing it
over the wallmt, and then
raising the point of the truss
with a long pole.
TEMPORARY PURLINS
STEP 5. Put the end trusses first,
/i
TRUSS .
bracing them from the ground. Then
run a string from apex to apex and
align the other trusses with the
string.
4
J/N
,LS AS TRUSS SUPPORTS
STEP 6. Hold the trusses in place
with temporary purlins nailed to
each one'. Then tie the rafters down
to the wall plate with bolts or
iron straps.
I RON
STEP 7. Next, construct the
purlins on the ground, rather
than on the roof. Stagger the
joints in the purlins to avoid
sagging in one section of the
roof. Be sure that no joints
are placed directly over a
truss beam: too many nails will
split the l-umber of the truss.
STEP 8. Attach the purlins to the trusses, starting 20cm from
the top of each one. The position of each purlin should be
marked in advance by running a string from end-truss to end-truss
and placing a nail at the purlin-point on each truss (the nail
will keep the purlins -from sliding until they have been attached
by bolts or iron straps).
For local roof-covering materials such
as tile, mud, or thatch, space the
purlins according to local
practice. For sheet metal, use
the following formula:
178
Where x = Space between purlins,
Y = Length of metal sheets, and
1Ocm = the length each sheet will overlap the one beneath it
X Y - 1Ocm
=
2
%AMPLE:
If
200~71 sheeting will be used, the
fomlu
would then yield:
2oocm - 1ocm c 2 = 19ocm + 2
=
95cm
betieen each purlin.
STEP 9. Attach the roof-covering
material. Again, follow local
practice for local materials.
Corrugated sheets should be
attached with specially galvanized
large-headed nails through the tops
of the curves,
wt in the valleys,
of y
each sheet. Piq ,.
Nail the sheets through
attemate
L 7 - 1
rises wherever the sheets overlap. +,~..,. nTTAPU ;\reav
Nail them every
third
rise in the
middle of the sheets.
The nailing should begin at the ‘(
bottom of the end of the roof
farthest from the prevailing wind
to minimize wind and rain that
will blow between the sheets.
For example, if the winds
come
mostly
from the east, begin at the
lowest part of the western end of
the building.
Stagger corrugated metal covering
so that each row of sheets covers
the joints of the row beneath.
Take care also to stagger the nails
so they do not form a straight line
along any purlin. Such a straight
line might split the purlin
underneath.
Patch any small holes in the
metal with "Masticon" or a gummed
metal tape called "Flashband".
NOTE: Metal Sheet Should be Staggered
STEP
10.
Build a crown to cover
the top of the roof by cutting
metal sheets lengthwise into
3 parts, pounding each part flat,
bending it over the ridge of
the roof, and nailing it to the
metal sheets and purlins.
179
24?.801 0 - 77 - I4
Bamboo is an excellent building material for several reasons:
l
it has a very high strength-to-weight ratio -- very
sturdy for such a light-weight material;
*
it is easily handled, with little waste and no bark
to remove;
l
it adapts to a variety of uses; a few bamboo plants
in the backyard will provide enough bamboo for a
fence, a pigpen, extra rooms, or a house;
0 after construction, bamboo can be used for other
income-generating crafts such as baskets, mats, and
so on.
About the onlypartsof a building that cannot be made rrom bamboo
are fireplaces and chimneys. However, bamboo is rarely used as
the only construction material for a whole building. Usually it
is combined with other materials: wood, clay, lime, cement, iron,
palm leaves, thatch, and so on.
There are many bamboo species. They differ in thitKness, strength,
flexibility, and resistance to insects and decay. Each is useful
in only a few parts of a building. For example, a species that
makes good supporting columns cannot be used to make screen matting
for a window. The general characteristics of different species are
discussed below. But when in doubt about a specific bamboo supply,
the best thing to do is check local practice and/or seek advice
from a local contractor.
To balance its advantages, bamboo has many drawbacks as a
construction material:
l
Uneven Dimensions. It is
necessary to ha-ve a large
supply in order to weed
out pieces that are too
thin, too crooked,
broken, or otherwise
useless.
l
Uneven surfaces.
Variations in the
diameter of the shaft
(called a culm), in the
prominence of the nodes,
and in the rate of
tapering at the end of
the culm all make
certain applications
difficult. On the
usually FQI
other hand, long culms can
often be cut up and the tips
used for one purpose while
the shafts are used for
another.
l
Brittleness. In almost all
cases bamboo cannot be
nailed. Most bonds are made
with wire or hemp lashings.
A few thick-walled species
can be bored to insert pegs.
0 Low durability. Bamboo is
susceptible to insects
(especially beetles and
termites) and to rot. Both
insect decay and rot can be
chemically retarded, and
some species are more
resistant than others. But
even in the best cases, bamboo cannot
last much more than
5 years
in weight-bearing parts of a building.
183
Bamboo for Foundations
Bamboo is basically an above-ground material. Unless it is treated
with a preservative, it will last only
2-3
years underground.
However,
stilts, bamboo will serve as a supporting post: for a house on
for example. Use the largest diameter culms (at least
12-20cm) with closely spaced nodes for stiffness.
'smaller shafts are available, they If only
can be bound into columns.
Bamboo for Frames
In earthquake areas, bamboo's
flexibility makes it a good choice
for construction of a frame for
floors, walls, and roofs; Such a
frame may then be finished by
weaving bamboo to form the solid
parts of the building, or by using
other materials such as clay, mud,
or thatch.
Use only whole culms. Cut off and
discard the upper, tapered ends of
each culm so that all shafts used
will have uniform thickness and
strength.
247-80, 0 - 77 - 13
(STUD
?
184
The design of a bamboo frame is simple:
Begin with corner posts firmly planted in the corners set out at
the site. Next, attach joists (horizontal cuPms that will support
the floor and roof). Then attach studs (vertical culms that will
form the wall frame).
Since bamboo cannot be cut to make perfectly measured joints, the
shafts must be lashed with vinesp bark, or wire. The only cut that
cun be made is a notch or cradle-like cut that can be used at the
upper end of posts to support a horizontal piece.
Bamboo for Floors
185
The culm of certain species can be split open and flattened out,
making a "board". Among other uses, these boards can be laid
directly on a hard earth surface to make a floor.
best soil for this purpose. Clay is the
It
should be evenly graded (for
proper drainage) before the boards are pounded into place.
BAMBOO BOARDS MADE BY SPLITTING
LARGE CULM AS SHOWN
Another type of bamboo floor is raised
1.5-2
meters so that
space underneath may be used for storage of equipment or anj
Thick culms are used as column supports* thinner culms are
flattened for the floor; and woven mats'are used as floor
covering,
I I
the
.mals.
Bamboo for Walls
Here are two common ways to use bamboo
for walls:
. Wide bamboo shafts are lashed
horizontally to both sides of
vertical hardwood posts.
Occasionally thick bamboo posts are
used instead of hardwood posts. The
spaces between the bamboo shafts may
be filled with mud, mud and stones,
thatoh, or more bamboo.
l
Sprung Strip Construction. Vertical bamboo shazts are woven
* _.
around three horizontal poles. The frame is then covered wltn
plaster on one or both sides.
OF PLASTER
DL ,AYER OF PLASTER
Partitions may be made exactly as walls are but with .lizE;a;,and
portable frames. Use the lightest species available.
flatten the shafts; then weave them into
mats
that can be suspended.
Bamboo for Doors and Windows
For practical reasons, doors
and windows are kept to a
minimum in bamboo housing.
Doors tend to be made of:
e wood: or,
. bamboo matting woven on
a bamboo frame: or,
. bamboo "bars" put up in a
gate-like fashion.
Windows are usually unscreened and
covered with bamboo matting or a
palm leaf. They can also be made
out of a row of shafts tightly
pressed and bound together by pieces
of wood: this kind of window, when
raised, acts as a shade'.
Bamboo for Roofs
Bamboo is used for the frame of the roof. The roof covering can
be of several materials:
. grass thatch;
e corrugated
metal
or asbestos:
. tile;
b bamboo tiles made from.halved culms.
188
Bamboo Weimforcern~t of Concrete
Bamboo can'be used to increase the strength of concrete by 2 to 3
times. To be effective, the shafts must be "seasoned" - dried
out and shrunk for a month or more and then split in half.
The placement of the shafts is the same as the placement of iron
reinforcement rods (see the section on reinforcing concrete,
page 137).
Preservation of Bamboo
The following simple steps will lengthen the useful life of
bamboo:
. Cut the shafts at the base and store them upright in
clumps in a dry, sheltered place. Never store bamboo
out in the open or expose it to rain or dampness: It
may rot or be eaten by insects.
. Dust the ends of each shaft with a mixture of 1:20 DDT to
talc (or other, safer insecticides where available and
effective).
. Use pegs to keep the ends off the ground.
. After 4-8 weeks of-drying, trim all twigs and leaves off
the shafts and dust the newly cut surfaces.
4
5 LATRCNES
190
LATRINES
Latrines are vital for community
health. They keep local watar used
for drinking or growing crops free
from diseases spread through
human feces; and they discourage
transmission of diseases by flies
that breed in excrement.
In
many areas, community
acceptance of latrines as an
integral part of any home,
school, or clinic project may be
more important than any other
construction ideas in this
manual.
Basically, a latrine consists
of: a
p&t
dug in the ground for
the storage of excrement; a
base
built over the pit with a small
hole in it so that a person can stand over the pit; and a
shetter
to
provide privacy, protect against weather, and to keep flies from
breeding in the pit.
Two principal requirements should govern the choice of a latrine's
location:
* It should be close enough to the school, clinic, or home to
be reached easily; but far enough away to keep the main
building
free of odors and potential contamination. 30 meters
is the distance recommended by many experts.
* It should be situated so
that it will not contami-
nate ground or surface
water that may enter
springs, wellsip or
fields. Satisfying
this requirement can
sometimes be complex.
The most important considera-
tions to keep in mind are:
l
the latrine should be high
enough so it will not be
flooded during the rainy
season;
191
. the latrine should be &x.m~iZLfrom any nearby wells or springs;
if this is impossible - of if the land is flat - the
latrine must be at least 15 meters away from wells or springs
(?.5 meters in sandy soil);
l
in regions with fissured rocks or limestone foundations
(which can carry pollution great distances),
get expert advice!
At the chosen location, begin by digging a pit, either ro;;: or
square, about 1 meter across, and from l-3 meters deep.
table below shows recommended depths for a latrine for a family
of 5. The same depths may be used for latrines in public
buiidings such as schools or clinics provided there will be 1
latrine for every 15 people who use the building regularly.
RECOMMENDED DEPTHS FOR HOLES WITH 1 SQUARE METER AREA
PERSONAL CLEANSING MATERIAL
w-s-
On the table, Wwet pit type" refers to pits which penetrate the
warer table in the ground and are constantly wet. "Dry pit type"
refers to pits that are 3 meters or more above the highest
underground water level.
If the soil is soft and tends to cave in during the digging, line
the pit with stone, brick, wood, or bamboo to keep the sides of
the pit strong. Even when the soil is firm, it's a good idea to
line the upper few feet.
The base is essentially a foundation for the floor. It also helps
to prevent hookworm larvae and burrowing rodents from entering the
pit.
The best materials for the base are concrete from a 1:2
:3
mixture,
or stabilized earth with S-6% cement content. Heavy hewn logs
treated for insect resistance ray also be used as shown.
Following construction of the base,
a mound of Shard-packed earth or dry
fill should be built up until it is
level with the top of the base (at
least 15cm above ground level), and
it covers the floor area planned
for the shelter.
Above this mound must be placed a
floor with a built-in hole about
40cm
long and 12-18~~1 wide.
Do not
make the IioZe tier than 18em or children
may fall
through it!
The shape of the hole can vary
according to local preference. Two
common shapes are shown.
l&m
-I
12cm
Q
193
The floor may be built of several materials. Reinforced concrete
is best. Build a form about 1OOcm x 1OOcm and 6cm deep. Then
cut a piece of wood 6cm high and the size and shape of the hole
desired. This piece will act as the mold for the hole in the
concrete slab. If you slope its sides slightly instead of making
them straight up and down, it will be easier to remove from the
concrete after the concrete has set.
Place the wood piece inside the 1OOcm x 1OOcm form where you
want the hole to be. Then place reinforcement rods (bamboo or
iron) in a grid across the formwork.
Mix, pour and cure the-concrete as you would for any concrete
floor (see pages 154-156). After curing,place the concrete slab
over the mound and base so that the hole is centered over the
pit opening.
Other materials appropriate for
building latrine floors include
reinforced brick mortar, wood,
and logs with earth.
It may be desirable to add raised
foot rests, approximately 30cm
long and 1Ocm wide as shown.
In addition, a simple wood cover
can greatly reduce odors and keep
flies away from the pit.
Shelter
The latrine shelter serves several purposes:
.
. protection from wind and rain;
. privacy;
. protection of the pit from direct light (darkness keeps flies
and other disease-carryivg insects and rodents from breeding
in the pit).
In general,
long, the shelter should be about 1 meter wide, 1.5 meters
and 1.5 meters high.
It should have a shed roof with a large overhang (about GO-100cm).
The roof should be lo-15cm above the walls for ventilation to
diffuse any odors which might build up.
If acceptable socially,
2 meters of the shelter, it is best to cut all vegetation within
especially if food is grown nearby.
This will prevent contamination of the ground surface resulting
from any possible misuse of the latrine.
The illustrations above show two types of latrine shelter. The
actual construction of latrine shelters follows the normal
procedures for any building.
One final note: The latrine design described in this manual is
only one of the many possible designs. See the sources listed
in the bibliography (page 227) for information on other designs.
STRUCTION EARTHQUAKE AREAS
196
CONSTRUCTiON IN EARTHQUAKE AREAS
In areas where earthquakes or tremors are likely, there are a
number of ways to reduce the danger of structural damage and to
increase the safety of those who use a building. Special care
should be taken in:
. the selection and preparation of the site and the
building position;
a
the selection of building materials;
. the use of special techniques for reinforcing
foundations, floors, walls, and roofs.
Sdectiore and Preparation of the Siie
One of the simplest precautions against earthquake destruction is
to choose a site as far as possible from the fault line. The
fault line is the line along which two blocks of earth meet and
slide against each other. Earthquakes occur when two such blocks
of earth move suddenly.
In areas where a serious ez r+hu-ke has occumed recently,
people near the fault line will know where it is. Fault lines
may also be found by looking for places where geological
formations such as dry river beds or veins of rock appear to
have suddenly split and shifted. The location of such shifts
will be on the fault line.
197
Other suggestions for the
selection of a site in
earthquake areas include the
following:
- Flat terrain is best;
avoid: sharply sloping
ground if possible; ground
slippage occurs most often
on hills.
- If the land has some slope
to it, level the
entire
site around the building
so that the foundation and
walls are the same height
throughout. Stepped
foundations and walls of
un-equal height are less
stable.
- Do not build on "filled-in"
earth: it can't be as stable
as ground that has settled
naturally over time.
- Align the building so that
its length is parallel to the
nearest fault line. This
will help the structure go
"with" and not "against" a
tremor.
-. Choose a site as far from
other buildings as possible.
The minimum distance between
l-story structures should be
equal to their height.
STEPPED FOUNDATION IS INCORRECT
(Wall Height Unequa 1)
LEVEL FOUNDATION IS CORRECT
(Wall Height Equal)
with fault line.
198
- If a new building must be
tdilt less than the minimum
distance .from another
building,
any separation is
better
than rwne. Never
interconnect the walls
of two
buildings.
- Use rectangular or circular
shapes for buildings in
earthquake areas. Avoid
"L-shaped" buildings.
INCORRECT: Walls Connected
CORRECT: Bui 1 dings Separate
Selection eb Building Materials
Generally, the safest materials in earthquake areas are the
lightest and most flexible.
In foundat&ms,
concrete footings reinforced with iron or
.bamboo,and concrete or block foundation walls are good. Avoid
rock foundation walls because the large amounts of mortar used
to bind the rocks are easily weakened in earthquakes.
For
waZZs, where climate permits, bamboo and wood are the best
because their flexibility keeps them from cracking or collapsing,
and because they are less dangerous if they do fall. Walls made
from bricks or blocks of any material are fine but should be made
as light and as thin as % ossible. F&mmed earth walls and rock
walls are unstable and angerous in earthquakes: they should be
avoided.
Roofs
are safest when made of bamboos and grasses (thatch).
Wood-beam supported roofs are also fine, provided the material
they support is light, such as shingles or corrugated metal.
Adobe and tile roofs should be avoided.
Reinforcemeht
of
Buildings
There are many ways ofreinforcing buildings to resist earthquakes.
The most important and least expe;?sive techniques are listed
here. But if earthquakes.are a major problem in the local area,
the field worker or community should consult experienced local
contractors for advice.
199
All of the techniques listed here can help save a building in an
earthquake, whether they are used alone or in any combination.
They cannot guarantee that a building will survive a severe
earthquake intact. But even in the worst case, they will give
people more time to get outside safely, before the building
collapses.
To strengthen foundations and floors, reinforce them with bamboo
or iron rods.
To strengthen walls:
. place windows and doors on opposite walls:
. place .Inside doors as close to the middle of interior walls
as pass-%le;
. place timbt: posts at the ends of interior walls (see the
section on window and door frames, page 96, for details of
construction);
l
mount exterior doors so they
open to the outside (this
permits faster escape during
a quake);
. allow at least 1 meter of
wall space between openings
and corners;
. connect all walls with
interlocking wooden beame
at the tops of the walls,
and preferably at the
floor and lintel levels
too;
reinforce wooden frame
walls with cross- supports:
TS
. use a "tight" bond between
brick or block courses; too
much mortar will weaken the
wall.
.
APPENQICES
-e
202
1. CALCULATIONS TO CHECK WHETHER A PROPOSED SITE WILL
SUPPORT A IBUILDING
If there is doubt whether the soil at a proposed site will
support a building (see page181 it may be necessary to estimate
both
the we{ght
of
the planned building
and
the weight-bearCng capacity
of
the soil.
This section contains step-by-step directions and tables
for both these estimates.
IMPORTANT NOTE:
The weight of a planned building cannot be
estimated until the builders have decided:
a
its size and shape (page 22-43);
l
what'its walls will be made of and how thick they will
be (page 92-951;
. what kind of roof it will have (page
101-114).
CALCULATING A BUILDING'S WEIGHT PER SQUARE METER
Several calculations must be made to estimate a building's weight
per square meter. For the purposes of estimation, figure that:
Equuttin 1. weight
of
longest + weight
of roof
mzt (kg)
supported by
Weeht per = longest 7xrlZ (kg)
square meter length
of
longest wall (ml
To find the weight per square meter, therefore, the planner first
needs to determine each of the three items on the right side of
Equath 2.
Follow these steps:
STEP 1. Enter the planned length of the longest wall in
Equation 1:
Equation 1. weight
of longest +
weight
of roof
wall (kg)
supported by
Weight per
squure meter = longest w&i?1 (kg)
STEP 2. Calculate the weight of the longest
wall.
Equation 1.
Weight per
squaxe meter length of longest waZ1 Cm)
(a) Use the following equation to determine the
weight of the longest’wall :
Equation 2
Weight
of
longest wall = weight pf
1
sq. meter
of
wall x number of sq. meters
in longest
wall
(b) Use Table A to find the weight per sq. meter for every centimeter of wall
thickness of the material with which the building’s walls will be built.
Table A
kg/sq. meter
wall material per centimeter
wall thCckness
(c) Multiply the number you find in
Table A by the thickness of the
building’s walls. The result will
be the weight of 1 sq. meter of
wall ; enter it in the correct
place in Equation 2:
concrete block 90
stabilized earth
125
sand-cement block 75
adobe
125
stone/rock 150
Equation 2
WeCght ,of
longest ml1 =cv)x n~~e;;.~er
(d) Next, multiply the length of the longest wall in meters by its height.
The answer will be the number of sq. meters in the wall. Enter this
figure in the correct place in Equation 2:
Equation 2
Weight
of
= weight
of
1 sq. meter x
of
sq.
longest wall
of
wall in longest wall
203
the weight of the longes t wall based on
in Equation 2 in steps 2 (c) and 2(d). the fi gures you have
STEP
3.
Estimate the weight of the roof supported by the
longest wall.
Equution 1
Weight Per
sP=e .meter
=
weight of longest
wa:.l (kg)
- length of longest till (m)
(a) Use the following equation to
estimate the weight of the roof
supporeed by the longest wa9 1:
We*t
of
roof
szgported by =
longest watt
t&ght of roof x nwnberof
per sq. meter
sq.
meter8
in. mop
(b) Use Table 6 to find the estimated
weight of the roo.f per sq. merer.
If you are in doubt about the
roof-style planned, use the
figure on the table for flat
roofs. Enter the figure you
find in fable B in Equation 3:
Roof Style
pitched
flat
Roof load
per sq. m
1707cg
19okg
Table
B
Equatimr3
Weight of
mof
supported by =
longest 7x111
205
(c) Next, multiply the length of the roof
by its width. If the roof has not
been planned yet, assume that it wi 11
be 1 meter longer and I meter wider
than the building. The answer will
be the number of square meters in the
roof. Enter this figure in the
correct place in Equation
3:
Equation 3
Weight of weight
of roof
roof
supported by = per sq. meter
longest waZ.1
(d) Compute the weight of roof supported by the longest wall using the
figures you have entered in Equation 3 in steps
3(b)
and 3(c).
STEP 4. Enter the figures you calculated in steps 1, 2(e), and
3(c) in Equation 1, and calculate the weight of the building per
square meter:
Equation l-
i
From 3(c) :
From 2(e) :
weight of-&of
weight of longest + supported by
STEP 5. Finally, compare the
building's weight per square
meter
with the weight-bearing
capacity of the soil at the
site indicated in Table C.
TabZe C
Weight-Bearing
Type of SoCl Cupacitg (kg/sq. ml
soft, b&z&, 4,9OU-10,000
&Sned marsh,
or
t'filllr
GraveZ, sand 29,400
Hard-packed clay 58,800
Rock 156,800
206
8.7m
SZQYPLE CALCULATION OF A BUILDING'S WEIGHT PER SQUARE METER
Here is a step-by-step sample of how the weight of a building
would be estimated,
202-205.
following the procedure outlined on pages
Assume that the building pictured above is planned to be 7.5
meters long and
2.4
meters high along its longest wall; assume
also that the walls will be made of 20cm thick sand-cement
blocks, and that the roof will be 8.7 meters long and 3 meters
wide, with a pitched design. If the site selected for the
building is soft, dark soil that can support 4,900 kg/sq. meter,
can the building be constructed as planned?
Here are the calculations:
-Equation 1 weight
of roof
weight of longest + supported by
Weight per wall (kg) longest wall (kg)
square meter = length
of
longest nail
STEP 1. Enter the length of the longest wall in Equation 1:
Equation 2 weight of roof
weight
of
longest + supported by
wu1.l (kg) longest watt (kg)
Weight per
square meter = (SE]
‘+
/
:,~.
I’
STEP 2. Calculate the weight of the longest wall.
(a) Use Equation 2:
Equation 2
Weight
of
longest wall = weight
of
7 sq. meter number
of
sq. meters
of
wizzz
X
in longest wall
(b)
Use Table A, page
203,
to find the wall’s weight per square meter for every
centimeter of wall thickness.
Yae build&g's walls will be made
of
sand-cement blocks which Table A
says weigh 75 kg/sq. meter
for every
centimeter
of
wall thickness.
(c) t4;4;Lply the figure you find in Table A by the thickness of the building’s
. The result will be the weight of 1 square meter ,of wall. Enter
this answer in the correct place in Equation 2.
!l%e sand-cement blocks that will be used will be 2Ocm thick. So a
wall made
of
these blocks will weigh 75 kg/sq. meter x 2Ocm thick =
1500 kg/square meter.
Entering this answer
in
Equation 2:
Weight
of
longest till = x nzunber
of
sq. meters
in longest wall
(d) Multiply the length of the longest wall in meters by its height and
enter the result in the correct place in Equation 2.
The longest wall
of
the building will be 7.5 meters long and 2.4
meters high. 7.5 x 2.4 = 18 square meters.
Enterixg this answer in Equation 2:
Weight
of
longest wall
=
1500
kg/sq. meter x (,,.)
(e) Compute the weight of the longest wall based on the figures you have
entered in Equation 2 in steps 2(c) and 2(d).
1500 kg/sq. meter x 18 sq. meters = 27,000 kg. Entering this result
in
EQuation 1: weight
of
roof
Weight per Q5G-G) + suported by
square meter = Zongest wall (kg)
\-
7.5
meters
207
208
STEP 3. Estimate the weight of the roof supported by the
longest wall.
(a) Use Equation 3:
Equation3
Weight
of
POOf
supported by = might
of roof x nwnber of
per sq. meter sq. meters
longest wall in
roof
(b) Use Table B, page 204, to find the estimated weight of the roof per square
meter. Enter this figure in the correct place in Equation
3.
The
zvof
is pZmrned with a pitched roof that Table B says will weigh
about 170 kg/%q. mter.
Entering this answer in Equation 3:
Weight of
mof
supported by
Zongest wall
nwnberof
sq. meters
in
roof
(c) Multiply the length of the roof by its height to find the number of square
meters of roof space planned. Enter this figure in the correct place in
Equation 3.
The
roof
is plunned to be 3 meters
with
and 8.7 meters long.
3mx8.7m = 26.1 square meters.
&teting this answer in Equation 3:
Weight
of
roof =
170
kg/sq. meter x
6.1
square meters
supported by
longest wall
(d) Compute the weight of roof supported by the longest wall using the
figures you have entered in Equation 3 in steps 3(b) and
3(c).
170 kg/sq. meter x 26.1 sq. meters = 4,437 kg. Entering this
result
in
Equation 1:
Weight per 27,000
kg
+
square meter = (TEEiks)
7.5
meters
209
STEP 4. Calculate the weight of the building per square meter,
using the figures you calculated in steps 1, 2(e), and 3(c) and
Equation 1.
27,000 kg + 4,437 kg 31,437 kg
= =
4,191 kg/sq. meter
7.5
meters
7.5
m
The building WiZZ weigh approximatedty 4,191 kg/sq. meter.
STEP 5. Compare the building's estimated weight/square meter
with the weight-bearing capacity of the soil at the site. Use
Table C, page 205.
According to Table C, the weight-beating capacity
of
the soft, dark
soil at thCs site is 4,900 kg/sq. meter. Since this building will
weigh only 4;191 kg/sq. meter, the building can be built safely at
th$s site.
To determine whether the soil at any proposed site will support
a planned building, all the builder needs to do is substitute
the figures for his/her building and site in the step-by-step
equations on pages 202-205, as shown.
2. STEP-BY-STEP QIRECTIONS FOR DRAWING FOUNDATION PUANS
Two kinds of drawings are important aids to help the field
worker and community members visualize their foundation plans
and check their progress during construction:
l
a cross-section view of the footing and foundation
wall: and
a
a view from above of the footing and foundation wall
measurements,
When a community group is ready to begin construction of the
foundation, it's a good idea to help them build a small
demonstration section of footing and foundation wall that they
can use along with these drawings to check their progress. The
demonstration section will help everyone see what they have
planned to do; at the same time, it will give them practice in
the construction techniques and skills Lney must use on the
aktual foundatfm.
DRAWING A CROSS-SECTION VIEW OF THE FOUNDATION
Drawing a cross-section view of the foundation is simple. Here
are examples of a cross-section for a rock foundation and for
a block foundation wall.
as well: Roth drawings show concrete footings
ROCK FOUNDATION WALL
:.
a* - - ‘ .
.
.*
. FOOTING * v
J 0 .
BLOCK FOUNDAT I ON WALL
211
DRAWING FOOTING AND FOUNDATION MEASUREMENTS (VIEW FROM ABOVE)
Drawing the foundation measurements
as they would look from above is
also simple.
Here are step-by-step instructions
for drawing the foundation
measurements of a sample building:
1. Draw a solid line representing
the outside dimensions of the
walls of the building. This
line will also represent the
outside dimensions of the
foundation wall.
6
2.
B
Draw a second solid lineimide
the first one to represent the
inside dimensions of the
building's walls. This line
will also represent the inside
dimensions of the foundation
wall.
The space betueen the two
lines should be exactly the width
of
the plumed &!ZG to scale.
(OUTS I DE WALL
>
INStDE WALL b
(WIDTH OF WALL
3.
Subtract the width of the wall
from the planned width of the
foundation footing. Divide the
remainder in two and convert
the answer into the scale
dimension being used in the
drawing. This figure represents
the distance between the inner
side of the wal! and the inner
side of the fou dation footing.
4.
Draw a dotted line inside the
drawing of the walls. This line
represents the inner dimension
of the footing. The space
between it and the inside
solid line (step C2) should
be exactly the distance
calculated in step #3,
5. Draw a dotted line outside the
drawing of the walls. This Pine
represents the outer dimension
of the footing=. The space
between it and the outside
solid line (step #l) should
be exactly the distance
calculated in step R3.
I i
, .
k OUTS I DE EDG.E
OF FOOTING
213
r
6. On either side of the
drawing's
length,
add a
solid line exactly as long
as the longest wall (that
I
is, the longest outer
solid line).
7. On either side of the
drawing's
width
, add a
solid line exactly as long
as the longest wall
(that is, the longest
outer solid line).
C
D
8. Place a mark
along each line
from steps #6-7
wherever the
outer wall turns
a corner.
Indicate the
actual length
of each
straight section
of wall.
0
MARK D I MENS IONS CALCULATED I N
THE CIRCLES ON THE DRAWING
0
MARK DIMENSIONS CALCULATED IN
THE CIRCLES ON THE DRAWING
7!
I
I
I
I
I
I
I
I
I
I
I
I
I
-I
-c
I
I
I
I
1
i
i
I
I
1
I
I
-4
m 0 a
------a-- t
I
1
I
I
1
A-
---------- -------- -,J
J
I-
---------------- 1
I I
1 I
I
I I
!
--------------- 3
t
I
I
I
I
I
f
3
3
214
,
9. Outside the lines drawn in steps #6-7, draw two more solid
lines exactly as long as the length and width of the outer
dotted line. Mark these lines to indicate the actual length
of each straight section of foundation footing.
10. Underneath the completed drawing, write down what the footing
and foundation wall will be made of and their cross-section
dimensions.
11. The completed drawing is an actual scale drawing showing
the trenches that must be dug for the footing and the
dimensions of the foundation walls.
Completed foundation plans:
n
215
3. ESTIMATING THE AMOUNTOF CONCRETE NEEDED FOR A FLOOR
To estimate the amount of concrete needed for a floor, use
the following equation and table:
Equation.
Cubic meters of thickness of
concrete needed = concrete x floor area (sq. meters)
for floor Zuyer (ml
Table. SUGGESTED THICKNESS OF CONCRETE FLOORS
Purpose of Floor Thickness (ml
School, Clinic, House .lOO
Garage (for vehicles)
.I25
Farm storage (heavy
equQmwnt)
.150
STEP 1. Find the thickness of the concrete layer that should be
used for your building in the table, Enter this figure in the
Equation:
Cubic meters of
concrete needed
= for floor
STEP 2, Multiply the length of your
building by its width to find out what
floor space it will have. Enter this
figure in the Equation:
Cubic meters of
concrete needed = concrete
for floor
216
In cases where the building will not
be a simple rectangle, the total
floor area can be determined by
multiplying the length and width of
each separate room
and then adding the
areas of all rooms together.
Sample CaZcuZation:
Floor area Room 1 = 2m x 2.Om = 4.0 sq. m
FZoor area Room 2 = lm x l.Sm = 1.5 sq. m
Floor aTea Room 3 = lm x l.Om = 1.0 sq. m
Tote,' _PZoor Area = 6.5 sq, m
In round buildings, the floor area
will be the radius of the building
squared times 3.14. The radius is
the distance from the outside of a
circle to its center.
Sampi!e Calculation:
Floor Area = Radius (2m) x Radius i2m) x 3.14
= 4 sq. meters x 3.14
2m
= 12.56 sq. meters
STEP 3. Enter the answers you found in steps 1 and 2 in the
Equation and multiply them. The answer will represent the number
of cubic meters of concrete that must be purchased or made for
the floor.
Swnpte Calculation (u&g
figures
for round cI.inic shown above)
.
Cubic meters
of
thickness
of
concrete needed. = concrete x floor area (sq. meters)
for
floor
layer
(rn)
= .lOm x 12.56 sq. meters
/
1
2m
lm
= 1.256 cubic meters
I
4. ESTIMATING MATERIALS NEEDED TO BUiLD WALLS
217
This section gives step-by-step
directions for calculating the
materials needed to build three
types of wall: poured concrete,
rammed earth, and brick/block.
POURED CONCRETE AND RAMMED EARTH
To deter-mine how much poured
concrete or rammed earth he/she
needs, the builder must calculate
how many cubic meters of material
it will take to "fill" the wall
space.
Use the following equation:
POURED CONCRETE/RAMMED EARTH FORM
Equation.
Cubic meters
of
nnterial needed = thickess
of
x waZZ area Isq. meters)
fi3i
one wall
watZ (meters)
STEP 1. Decide how thick the wall will be (see page 94 for a
discussion of what to consider when planning wall thickness).
Enter this figure in the correct part of the equation.
STEP 2. Calculate the,wall area in square meters by multiplying
the wall's
Length
by its
width.
STEP 3. Multiply the answers you found in steps 1 and 2. The
result will be the cubic meters of crncrete or rammed earth you
will need to build
that
one waZ2.
STEP 4. Repeat steps 1 through 3 for
each wall
of
the buitding.
STEP 5. Add the cubic meters of concrete or rammed earth needed
for all the walls of the building. The result will be the
tot&
number of cubic meters
of
concrete
or
rarrPned earth you will need for the
buitdzng.
218
Calculating Baqs of Cement Needed for a Concrete Wall
Builders who plan to purchase the cement for their concrete need
to know how many sacks or bags of cement to buy. Once you have
determined how many cubic meters of concrete you will need,
finding the number of bags of cement is easy: just look the
answer up in Table 3, in Appendix 4 (page 222), To use the table,
first, find the concrete mixture you plan to use. In the case of
walls, the mixture would be 1:2 3/4 :4. The table will then tell
you how many cubic meters of concrete you will get from one sack
of cement. Divide the number of cubic meters of concrete you plan
to use by the amount you would get from one sack. The answer will
be the number of sacks of cement you need to purchase.
Calculating Wheelbarrowsful of Rammed Earth or Concrete Needed
Hanybuilderswant to know how many wheelbarrows full of concrete
or rammed earth they must bring to the construction site for
wall construction: this information gives them an idea of how
much work will be involved.
The number of wheelbarrowsful needed can be estimated by following
these steps:
0 Build a form exactly 1 cubic meter in size and count how
many wheelbarrowsful of rammed earth or concrete it takes
to fill the form.
. Multiply this number by the total cubic meters of material
that are needed for construction (from Step 5, page 216).
Your answer will tell you how many wheelbarrowsful are
needed,
BLOCK AND BRICK WALLS
To estimate the number of blocks or 1,
bricks needed to build a wall,
follow these steps:
STEP 1. Calculate the wall area
in square meters by multiplying the
wall's
length
by its
tvidth.
STEP 2. Note down the nominal size
of the block face. The nominal face
of a
block is the height and length of
the block surface
visible in
the watt
after the block is laid.
Calculating Mortar Quantities
The amount of mortar needed to bond the blocks/bricks for a
building depends on the number of blocks/bricks and their
size. To calculate the amount of mortar needed for Icm thick
mortar joints, follow these steps:
Divide the number of blocks needed for the building by
l 100.
For example,
1536 + 100 = 15.36. if the building requires 1,536 blocks,
l
Use the table below to find the cubic meters of mortar
needed to lay 100 blocks. For example, if the nominal
size of the blocks used will be 1Ocm x 20cm x 40cm,
.073 cubic meters of mortar would be needed to lay every
100 blocks.
l
Multiply the answers found in the above steps. For
example, if 1,536 blocks of nominal size 1Ocm x 20cm x 40cm
are needed for a building's walls, multiply 15.36 x .073.
15.36 x .073 = 1.12 cubic meters of mortar. Table 7 in
Appendix 5 (page 224) may be used to determine how much
cement, lime, and sand yo;l will need to make the mortar
required for any building.
QUANTITIES OF MORTAR REQVImD
TO LAY 100 Bs!X'WSfBRIC~
(Mortar
for
Joints lcm Thick Includhag 25% Alhxznce for Waste)
Nom-hat Siie of
cubic Meters
BlOCks/B2+&3 of
(Cd Miwtar
10 x
13.25
x
30 .053
15
x
13,25
x
30 "053
20
x
13.25
x
30 ,067
10 x
15
15 x
15
20
x
15
10 x
20
15 x 20
20
x
20
10
x20
15 x 20
20 x 20
25 x 20
30 x 20
15 x
15
20
x
15
25
x
15
30
x
15
x
30
x
30
x
30
x
30
x
30
x
30
x
40
x
40
x
40
x
40
x
40
x
60
x
60
x
60
x.60
,065
,065
,070
,061
,061
,076
-073
-073
.og2
,092
l 092
t 092
.r15
,115
,115
r
XI
5. REFERENCE TABLES FQR CONCRETE CONSTRUCTION
r
TABLE 1
Recommended Thickness of Concrete Slabs (cm)
Basement floors for dwellings 10
Porch floors 10-12.5
Stock barn floors 12.5-15
Poultry house floors 10
Hog house floors 10
Milk house floors 10
Granary floors 12.5
Implement shed f loot-s
15
Tile floor bases
6.25
TABLE 2
Quantities of Materials Required to Build One Cubic Meter of Concrete
(for Aggregates 2.5 Centimeters or Less)
Mixtures Barrels of Cubic Meters
Cement of Sand Cub i c Mete rs
of Stone
1:1:1*
1:1:2
1:1:23
1:1:3
1:1$:2
l:lf:3
1:l 3/4:2
1:l 3/4:2t
1:l
3/4:2 3/4
1~2~3
1:2:3&
1:2:4
1:2:5
1:2%:23
1:2+:3
1:2&:4
1:2%:5
1:2&:3
: 3
. .
1;2&4&
1:2f:5
1:2 3/4;4
1:3:4
1:3:5
1:3:6
3.56
3.23
2.90
2.64
3.04
2.44
2.75
2.64
2.44
2.24
2.07
1.95
1.73
2.32
2.18
1.31
1.68
2.11
1.98
1.82
1.82
1.62
1.74
1.66
1.49
1.36
.40
-36
.33
.30
.43
.42
.54
.51
.47
.50
.48
.44
.39
.59
055
.48
.42
:Z
.51
.48
.46
.54
056
.51
746
.60
2:
.83
.68
.84
.62
.67
.80
237
.88
25
.74
.86
.94
l
71
::2"
.87
.91
-79
-75
.84
.92
221
222
Concrete
Mixtures
l:l:l$
1:1:2
1:1:2f
1:1:3
1:1&:2
l:lf:3
1:l 3/‘+:2
TABLE
3
Volume of Concrete Construction per Sack of Cement
for Aggregates Not Larger than 2.5 Centimeters)
Cubic Meters of Concrete Concrete Cubic Meters of Concrete
Per Sack of Cement Mixtures Per Sack of Cement
.07
1:2*:23 10
.08
1:2&:3 :l?
.03
1:2&:4
13
.lO 1:2%:5 :15
.08
1:2&:3 .12
.lO
1323333 13
l 03
1:2+:4
:14
it1 314~2%
10
l:2*:4i l5
1:l 3/4:23/4 :10 1:2+:5
:15
1:2:3 .ll 1:23/4:4 .14
1:2:33 .12 1:3:4 .14
1:2:4 13
1:2:5 :14 1:3:5 17
1:3:6
:18
TABLE
4
Suitable Mixtures for Various Concrete Construction Projects
Floors
. One Course 1-:1
3/4:4
. Heavy Duty, One Course 1:1:2
. Farm Buildings 1:2%:3
Foundation Walls and Footings
1:23/4:4
Basement Wa 11,s 1:23:4
Tanks 1:2:3
Fence Pos t s l:l:l&
Retaining Walls
1:2:3f
Ba rnya rd Pavements 1:3:5
Lintels
1:2:4
Beam Filling 1:3:4
Silo Pits
1:2t:3
Steps
1:2t:3
Concrete Mixture
Wall Thickness <cm)
(Nominal)
Size of Brick (cm)
6.5
x 10 x 20
7.5
x 10 x 20 10 x 10 x 20
5.6
x
9.4
x
20
10
730 650 485 6C5
20
1455 1300
970
1330
iz::
2075
1950
1455
1335
2910
2600
1940
2660
,:-,3:
>s ”
“_
,<c,;. ‘(
223
TABLE
5
Approximate Number of Bricks Required to Bui Id
10 Square Meters of Exterior Wall Surface
(Mortar joints 1.25&m thick)
TABLE
6
Mortar Required to Lay 1000 Bricks
With 1.25cm Mortar Joints
(10% AZZowance for Waste Incih.&d)
NOMIN,1L SIZE OF BRICK: 1Ocm x 6.5cm x 20cm 1Ocm x 7.5cm x 20cm 1Ocm x 1Ocm x 20m
WALL TH I CKNESS
1 OCITL
.32
CU.
meters $ cu. meters .36 cu. meters
20cm”-
.42
cu. meters * . meters -50 cu. meters
30cm**
.45
cu. meters
.47
“c”,. meters
.55
cu. meters
f Figures for 1Ocm thick walls include mortar for bed and end joints only.
** Figures for 20cm and 30cm thick walls include bed and end joint mortar
plus mortar for the vertical joints needed in double brick walls.
*,‘I-8L’1 0 - 17 - 16
TABLE
7
Materia.ls Required To Make 0.10 Cubic Meters of Mortar
Mortar Mixtures
By Vol ume
1 part cement
3 part clay mortar
3 parts sand
50kg Sacks 25kg Sacks of
of Cement Hydrated Lime Cubic Meters
or Clay Mortar of Sand
3.73
4.11 0.75
1 part cement
t part hydrated 1 ime 7.33
1.33 0.64
3
parts sand
1 part cement
1 part hydrated 1 ime
4.23
2.89
0.69
6 parts
sand
1 part masonry cement
3 parts sad
8.73 --mm 0.68
225
6. METRIC MEASUREMENTS USED IN
THIS IMANUAL AND
THEIR U.S.
EQUIVALENTS
LENGTH
1 meter (m) = 39.37 inches
= 3.28
feet
= 1.31 yards
1 centimeter (cm) = 0.01 meters = 0.3937 inches
1 foot =
0.3048
meters
1 yard = 0.9144 meters
1 inch = 2.54 centimeters
AREA
1 square meter = 10.76 square feet
bq. ml
1 square foot
= 0.3048
sq. meters
= 929 sq. centimeters
VOLUME
1 cubic meter = 1.308 cubic yards
(cu. m)
1
cubic
yard
= 0.7646
cu. meters
WEIGHT
--
1 kilogram (kg) = 2.2046 pounds
1 pound = 0.4536 kilograms
1,
”
I
::
, .,
226
I
7. SOURCES OF FURTHER INFORMATION
NOTE: Wherever possible, the address through which copies of the
following sources may be obtained has been listed. Several
manuals are unpublished materiai that may
Oni:'
be found in Peace
Corps files, Questions about these materials should be sent to:
Peace Corps
Information Collection & Exchange
806 Connecticut Avenue, N.W.
Washington, D.C. 20525
USA
BAMBOO:
1. McClure, F.A., Bamboo as a Building Material. U.S. Dept. of
Agriculture, Foreign Agriculture Service, 1970. Write to:
Dept. of Housing and Urban Affairs
Division of International Affairs
Washington, D.C. 20410 USA
2. United Nations Dept.
of
Economic and Social Affairs. The Use
of
Bamboo and Reeds in Building Construction. Publication
ST/SOA/113. Refer to sales 0 E.72.1V.3 and write to:
United Nations Sales Section
New York, New
York USA
CONCRETE CONSTRUCTION AND REINFORCED CONCRETE CGI,UM&jS:
3. Brann, Donald R. Concrete Work Simplified, Revised Edition,
Directions Simplified, Inc., 1971. Write to:
Directions Simplified, Inc.
Easi-Build Pattern Co., Inc.
529 North State Road
Briarcliff Manor, New York 10518 USA
4. Dalzell, James Ralph and Gilbert Townsend. Concrete Block
Construction for Home and Farm. American Technical
Society, Chicago, 1957. Write to:
American Technical Society
5608 Stony Island Avenue
Chicago, Illinois 60637 USA
5. Davies, John Duncan. Structural Concrete. MacMillan and CO.~
New York, 1964. Write to:
MacMillan Publishing Co., Inc.
Riverside, New Jersey 08075 USA
227
6.
Gibson, J. Herbert. Concrete Design and Construction. American
Technical Society, Chicago, 1951. Write to same address
as #4 on page 226.
7. Putnam, Robert. Concrete Block Construction, 3rd Edition.
American Technical Society, Chicago, 1973. Write to
same address as #4 on page 226.
8. Randall, Frank A. Jr. and William C. Panarese. Concrete
Masonry Handbook. Portland Cement Association, 1976.
Write to:
Portland Cement Association
Old Orchard Road
Skokie, Illinois 60076 USA
9. Waddell, Joseph J. Concrete Construction Handbook, 2nd Edition,
McGraw Hill Co., New York, 1974. Write to:
McGraw Hill Book Co.
1221 Avenue of the Americas
New York, New York 10036 USA
10. Winter, George. Design of Concrete Structures, 8th Edition.
McGraw Hill Co., New York 1972. Write to same address as
#9 above.
FOUNDATIONS AND FOUNDATION DESIGNS:
11. Brann, Donald R. Forms, Footings, Foundations, Framing.
Directions Simplified, Inc., 1974. Write to same address
as #3, page 226.
12. Carson, Arthur Brinton. Foundation Construction. McGraw Hill
co., New York, 1965. Write to same address as #9 above.
13. Chellis, Robert Dunning. Pile Foundations, 2nd Edition.
McGraw Hill Co., New York, 1961. Write to same address as
#9 above.
14. Ulrey, Harry R. Carpenters and Builders Library: Layouts,
Foundations, Framing.
1974. Write to: Theodore Audel & Co., Indiannapolis,
Bobb-Merrill Co. Inc.
4300
West 62nd Street
Indiannapolis, Indiana 46268 USA
BLOCK AND BRICK CONSTRUCTION (MASONRY):
15. Boudreau, Eugene H. Making the Adobe Hrick. Fifth-Street
Press, New York, 1971. Write to:
228
Bookworks
Random House, Inc.
457 Hahn Road
Westminster, Maryland 21157 USA
16. Busch, Lawrence.
Peace Corps: Construction With Pressed Earth Block (Togo).
write to address on top of page 226.
17. Dalzell, J. Ralph. Simplified Masonry Planning and Building.
McGraw Hill, New York, 1953. Write to same address as #9
above.
18. Dixon, Michael. Field Manual for Production of Bricks in a
Rural Area (Pakistan). Peace Corps: write to address on
top of page 226.
19. Frankly, Lee. The Masonry House:
Tile and Brick. Step-by-Step Construction in
Duell, Sloan, and Pearce, New York, 1950.
No address available.
20. Ray, J. Edgar. Revised by Harold V. Johnson. The Art of
Bricklaying. Charles A. Bennett Co., 1971. Write to:
Charles A. Bennett Co., Inc.
809 West Detweiller Drive
Peoria, Illinois 61614 USA
21. U.S. Dept. of Agriculture.
Earth Blocks. Building With Adobe and Stabilized
Dept. of Agriculture Leaflet No. 2535.
Write to U.S. Dept. of Agriculture, Independence Avenue,
Washington, D.C. N.W. USA
WOOD-FRAME CONSTRUCTION:
22. Anderson, Leroy Oscar. How to Build a.Wood-Frame House. Dover
Press, 1973. (Reissue of the revised 1970 Edition of the
U.S. Dept. of Agriculture Handbook No. 73, originally
pulbished by Government Printing Office under.the title of
Wood-Frame House Construction.)
%21 above, or to: Write to same address as.
L I
Dover Pubiications, Inc.
180 Varick Streeet
New York, New York 10014 USA '
23. Anderson, Leroy Oscar. Low-Cost Wood Homes 'for Rural America:
Construction ,Manual.
No.
364. U.S. Dept. of Agriculture Handbook
Write to same address as #21 above.
24. Blackburn, Graham.
1974. Write to: Illustrated Housebuilding. Overlook Press,
Overlook Press
c/o Viking Press
625 Madison Avenue
New York, New York 10022 USA
25. Brann, Donald R. How to Build an Addition. Directions
Simplified, Inc., 1975. Write to same address as #3,
page 226.
LATRINES:
26. Karlin, Barry. Thailand's Water-Seal Privy Program: A
Procedural and Technical Review. U.S.O.M., Korat,
Thailand. Write to the Peace Corps at the address on
top of page 226, or to the author at:
American Public Health Association
1015 18th Street, N.W.
Washington, D.C. USA
27. Wagner, Edmund G. and J.N. Lanoix. Excreta Disposal for
Rural Areas and Small Communities. World Health
Organization, Geneva, 1958. Write to:
Q Corporation
49 Sheridan Avenue
Albany New York, 12210
229
ORGANIZATION AND MANAGEMENT OF SELF-HELP CONSTRUCTION GROUPS:
D
28. Peace Corps (Jamaica). Manual for Supervising Self-Help
Home Construction with Stablilized Earth Blocks. Write
to address on top of page 226.
29. Warner, Jack R. Handbook of Construction: Peace Corps
Training Manual. Longmans Green and Co., London. Write
to address on top of page 226.
ESTIMATING CONSTRUCTION MATERIALS AND COSTS:
30. Cooper, F. Building Construction Estimating. McGraw Hill Co.,
1959. Write to same address as #9 on page 227.
GENERAL CONSTRUCTION
31. Alcock, A.E.S. and Richards. How to Build: Setting Out.
Longmans Co., London, 1960. Write to:
Longmans, Inc.
19 West 44th Street
Suite 1012
New York, New York 10036 USA
32. East Pakistan (Bangladesh) Public Works. Building Design
Manual. Dacca, 1965. Write to address on top of page
226.
D
33. Fullerton, Richard L. Building Construction in Warm Climates,
Volumes 1 and
2.
Oxford Tropical Handbooks, Oxford University
Press, London, 1967. Write to:
Oxford University Press, Inc.
200 Madison Avenue
New York, New York 10016 USA
34. Intermediate Technology Group. Intermediate Technology Series:
Manual on Building Construction. Parnell House, London.
Write to:
Intermediate Technology Group
Parnell House
London, ENGLAND
35.
Peace Corps (Togo). Construction Handbook: In-Country Training.
Peace Corps, 1974. Write to address on top of page 226.
36.
Uirey,
Harry F. Carpenters and Builders Library: Tools, Steel
Square, Joinery. Theodore Audel & Co., Indiannapolis, 1974.
Write to same address as #14, page 227.
37.
U.S. Dept. of Housing and Urban Development, Office of
International Affairs. Coma
Fabricar Unu Casa Us&. Tecnica
Ayuda Propia.
Government Printing Office, 1974. Write to
same address as #l, page 226, or to:
U.S. Government Printing Office
North Capitol Street, N.W.
Washington, D.C. USA
8. “HUMAN MEASURING PIECES” FOR DESIGNING ROOM SIZE
231
AND FLOOR PLAN
*
ACTION PAMPHLET NO. 4200.24 (9/77)

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