DP Installation Manual 2018 Feb

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INSTALLATION
MANUAL

Pin Foundations, Inc.

Gig Harbor, Washington
Toll Free: 866-255-9478 / Main Office: 253-858-8809
www.pinfoundations.com or www.diamondpiers.com

© 2018 by Pin Foundations, Inc. All rights reserved. DOC0007/02.2018

Diamond Pier® Foundation Systems are covered by U.S. Patents 5,039,256; 6,910,832; 7,326,003; and
patents pending.
Diamond Pier® is a U.S. registered trademark of Pin Foundations, Inc.
The latest version of this Installation Manual is available on our website, www.diamondpiers.com, or by
calling us at 866-255-9478 (Toll Free) or 253-858-8809 (Main Office).
Other documents and publications referenced in this manual are listed below and available at
www.diamondpiers.com.
National Evaluations
“Diamond Pier DP-50 & DP-75 for Bearing Pin Piers,” ICC-ES Evaluation Report No. ESR-1895, 2017.
State Evaluations
“Diamond Pier DP-50 & DP-75 Precast Concrete Pier Foundation Assembly,” Wisconsin Building
Product Evaluation, Code Approval No. 201612-O (Replaces No. 201008-O), November 22, 2016.
Observational Evidence
“Diamond Pier National Performance Submittals,” 2005.
“Diamond Pier Frost Performance Report, Zone II, Minnesota Soils,” 2010.
“Diamond Pier Observational Evidence, Forest Lake, Minnesota,” May 2011.
Building Code Compliance Documents
“Code Compliance Information for Diamond Pier Foundations in the State of Michigan,” Pin
Foundations, Inc., Revised January 2018.
“Code Compliance Information for Diamond Pier Foundations in the State of Minnesota,” Pin
Foundations, Inc., Revised January 2018.

CONTENTS
INTRODUCTION .......................................................................................................................................... 4
Soils .......................................................................................................................................................... 4
Pin Pile Technology .................................................................................................................................. 4
Diamond Pier Foundation System ............................................................................................................ 4
CONDITIONS AND USES ........................................................................................................................... 5
Normal Soil Conditions ............................................................................................................................. 5
Supporting Soils .................................................................................................................................... 5
Residential Diamond Pier Load Chart................................................................................................... 6
Use and Applications ................................................................................................................................ 7
Frost Heave .............................................................................................................................................. 7
Heave Resistance ..................................................................................................................................... 7
INSTALLATION INSTRUCTIONS ............................................................................................................... 8
Prior to Installation .................................................................................................................................... 8
Inspect for Underground Obstacles ...................................................................................................... 8
Locate Buried Utilities............................................................................................................................ 8
Check Your Layout ................................................................................................................................ 9
Assemble Tools and Supplies ............................................................................................................. 10
Inspect and Prepare Diamond Pier Components ............................................................................... 10
Install Inspection Plugs in Pins............................................................................................................ 11
Installation ............................................................................................................................................... 11
Identify and Mark Location .................................................................................................................. 11
Set the Concrete Head ........................................................................................................................ 11
Drive in the Pins .................................................................................................................................. 12
Encountering Obstructions .............................................................................................................. 13
Removing Pins ................................................................................................................................ 13
Place Pin Caps on Pins ....................................................................................................................... 14
Register Your Product Warranty ............................................................................................................. 14
AUXILIARY PARTS AND EQUIPMENT .................................................................................................... 15
Post/Beam Brackets ............................................................................................................................... 15
Breaker Hammers and Driving Bits ........................................................................................................ 15
FIELD INSPECTION .................................................................................................................................. 16
Pin Length Inspection ............................................................................................................................. 16
Pin Specifications ................................................................................................................................... 16
Concrete Head Integrity .......................................................................................................................... 16
Allowable Capacity ................................................................................................................................. 17
SPECIFICATIONS ..................................................................................................................................... 18
References/Standards ............................................................................................................................ 18
Delivery/Storage and Handling ............................................................................................................... 18
Pins ......................................................................................................................................................... 18
Connections/Posts/Beams ..................................................................................................................... 18
Site .......................................................................................................................................................... 18
Installation ............................................................................................................................................... 18
TROUBLESHOOTING ............................................................................................................................... 19

Diamond Pier® Installation Manual

3

INTRODUCTION
Soils
Pin Foundations, Inc. (PFI) has been designing and manufacturing foundations for over 25 years. One
thing has always driven our thinking—the Earth is the actual foundation, and soils, in their natural
undisturbed state, have the strength and structure to do the job.
Man-made foundations have two basic functions: to transfer loads properly into the Earth’s soil structure
and to provide a connection to the built structure above. There are two general types of man-made
foundations: deep vertical pilings (banged in) and shallow spread footings (dug in and buried). Pilings
keep the Earth’s existing soil strength and structure intact, and are easy to install if they do not need to
go too deep. Footings spread loads more widely, but the digging breaks apart the soil, weakening it and
blocking or exaggerating water flow.

Pin Pile Technology
Pin pile technology combines the best features of both types of man-made foundations. By grouping
short stiff piles (bearing pins), which can easily be driven into intact penetrable soils, and setting them at
angles to work more like a shallow footing, a sound foundation can be constructed that requires no
excavation. The pin pile group simulates nature’s design, resembling the roots of a tree providing
bearing, uplift, and lateral capacity. In recent decades, grouped pin piling has become a reliable technology for complex, heavy-duty commercial applications, performing a superior job of transferring loads
to intact undisturbed soils.

Diamond Pier Foundation System
PFI’s innovation is to bring pin pile technology into common use with a superior connector—the Diamond Pier
concrete head. This high-strength, precast component is
a driving guide, a pin piling lock, and a structural connection all in one. As a driving guide, the head maintains
the pin angles so that their capacity is definable and
consistent. As a lock, the head is designed to increase
its grip on the pin cluster when loaded up, down, or sideways—getting stronger and tighter as loads increase.
And as a connection, an embedded anchor bolt and
precast, post-matching shape make it a simple and
proportional complement to its supported structure.
This concrete head combined with the bearing pin group
Figure 1. Diamond Pier
forms the Diamond Pier system—a hybrid of familiar
Foundation
Components
concrete and steel materials. This system provides a
solid, stable, economical foundation that both captures
and preserves the supporting strength and natural functions of the Earth’s soil it's engaged in and, in
turn, solidly and simply connects to and protects the permanent structures above.
This manual provides information and instructions for installing Diamond Pier foundations in residential
applications in Normal Soil Conditions (see next section).

Diamond Pier® Installation Manual

4

CONDITIONS AND USES
Normal Soil Conditions
Diamond Pier foundations sold through retail outlets are designed for projects that are founded in normal
sound soils. Normal soils are typical in most residential neighborhoods throughout the United States and
are defined in the International Residential Code (IRC) Table R401.4.1. Presumptive Load-Bearing
Values of Foundation Materials.
For residential applications, the two most common prescriptive bearing soil types relied upon in the IRC
table, and in most local codes, are 2000 psf sands/gravels and 1500 psf silts/clays. Diamond Pier
foundations sold through retail outlets must be founded in soils with a minimum 1500 psf bearing
strength. Supporting soils that do not meet the presumptive bearing strength defined in the applicable
code for your area will not provide expected foundation capacity, and their bearing capacity may need to
be determined by a soils investigation. Ask your local code official for soil information regarding your
site. Additional soils information may also be available at the U.S. Geological Soils Survey website
managed by the U.S. Department of Agriculture—see http://websoilsurvey.sc.egov.usda.gov/.

Supporting Soils
Some soils may not be appropriate for supporting Diamond Pier foundations. Some examples include
soils that are weaker than 1500 psf, soils that are highly expansive, shifting or sliding soils, soils on
slopes greater than 2:1 (27 degrees), contaminated soils, or soils where traditional concrete piers,
accepted by local codes, are unable to provide adequate bearing to support the loads of the project or to
protect the structure from the negative effects of frost heave. Where unsound soils exist, a registered
design professional may be required to review the project.
Soils can also be weakened when they retain standing water or are improperly drained, and in certain
types of soil this can also cause heave problems. A site depression with standing water or the potential
for water to pond, pool, or saturate the soil may be an indication that the soil is not sound. Downspouts
that discharge at or near a foundation may also cause soil problems, and setting a Diamond Pier
foundation adjacent to any water body should be considered carefully. Depending on the variables
involved, soils at the edge of or within lakes, ponds, rivers, streams, or tidal zones may be considerably
weaker (as much as 40% or more) than dry or well-drained soils. Soils adjacent to existing foundations
may also have been improperly or loosely backfilled, which may also cause poor drainage or poor soil
conditions. Be sure to inform your project designer if any of these conditions exist.
Please contact PFI if you have any questions regarding your project or soil conditions, and/or the proper
use of the Diamond Pier product or “Residential Diamond Pier Load Chart,” provided in Table 1.

WARNING: You must check for underground utilities and follow the instructions
described under “Locate Buried Utilities” (page 8) before Diamond Pier
foundations can be installed.

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Residential Diamond Pier Load Chart
Table 1. Residential Diamond Pier Load Chart

IAS-Accredited Third-Party Bearing, Uplift, and Lateral Field Tests

2

Minimum 1500 psf

Silts/Clays (CL, ML, MH, CH)3

Model Pin
No.
Length

Bearing Load
Capacity

Uplift Load
Capacity

Lateral Load
Capacity

DP-50 / 36"

2700#

1.8 sf

18" dia

24"

600#

600#

DP-50 / 42"

* 3000#

2.0 sf

19" dia

36"

* 900#

* 600#

DP-50 / 50"

3300#

2.2 sf

20" dia

48"

1200#

600#

DP-75 / 50"

* 3750#

2.5 sf

21" dia

48"

* 1400#

* 600#

DP-75 / 63"

4200#

2.8 sf

22" dia

60"

1600#

600#

Uplift Load
Capacity

Lateral Load
Capacity



Equivalent
Base Area



Cylinder
Comparison



Frost
Zone

Equivalency to Traditional Concrete Footings

Minimum 2000 psf

Sands/Gravels

(SW, SP, SM, SC, GM, GC)3

Model Pin
No.
Length

Bearing Load
Capacity

DP-50 / 36"

3600#

1.8 sf

18" dia

24"

600#

600#

DP-50 / 42"

* 4000#

2.0 sf

19" dia

36"

* 900#

* 600#

DP-50 / 50"

4400#

2.2 sf

20" dia

48"

1200#

600#

DP-75 / 50"

* 5600#

2.8 sf

22" dia

48"

* 1400#

* 600#

DP-75 / 63"

6400#

3.2 sf

24" dia

60"

1600#

600#



Equivalent
Base Area



Cylinder
Comparison



Frost
Zone

Equivalency to Traditional Concrete Footings

*Interpolated from field test values.

Notes:
1. This load chart is intended for simple structures supported by columns, posts, and beams loaded up to, but not
exceeding, the stated capacities. It is not intended for structures with asymmetrical, rotational, overturning, or
dynamic forces. Intended uses are described in section 2.0 of ICC-ES prescriptive bearing evaluation report
ESR-1895. For projects that exceed the capacities or limitations defined herein, or the intended uses described
in ESR-1895, contact PFI for additional information or site-specific capacity evaluation. See also the Use and
Applications download at www.diamondpiers.com.
2. Capacities shown are tested to a Factor of Safety of 2, and are applicable in properly drained, normal sound
soils only, with minimum soil bearing capacities as indicated. Copies of the field test reports are available from
PFI upon request.
3. See IRC Table R401.4.1, “Presumptive Load-Bearing Values of Foundation Materials,” for a full description of
applicable 1500 psf and 2000 psf soil types. For soils below 1500 psf, or soils with unknown characteristics,
additional site and design analysis is required. For soils above 2000 psf, the values in this chart shall apply.
4. All capacities use four pins of the specified length per foundation. Pin length includes that portion of the pin
embedded within the concrete head. See “Check Your Layout” on page 9 for more information on pin/pier layout and
spacing restrictions.
5. For professional engineers designing for short-term transient loads, contact PFI for further information.

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6

Use and Applications
The intended use for Diamond Pier DP-50 and DP-75 foundations sold through retail stores is to support
simple residential projects constructed with columns, posts, and beams. The scope of project is defined
as decks, covered decks, walkways, stairways, and accessory structures or similar projects that meet
this intent. Project loads are limited to the capacities defined in the “Residential Diamond Pier Load
Chart” shown in Table 1. The load chart shows that Diamond Pier foundations provide equal or better
performance when compared to traditional concrete foundations claimed as equivalent.
In the residential load chart, “cylinder comparison” and “frost zone” values are given. These two values
define the size of the traditional concrete pier foundation that a given Diamond Pier foundation is
equivalent to in bearing capacity and frost heave resistance. For example, a DP-50 with 50" bearing pins
shows a cylinder comparison of 20" and a frost zone rating of 48". This compares with a traditional 20"
diameter, 48" deep poured concrete foundation. For more information, please refer to the Use and
Applications document at www.diamondpiers.com.

Frost Heave
Frost is not an unusual or unsound soil condition unless the site has a history of locally accepted
conventional foundations failing due to frost heave or freeze/thaw cycling. In frost zones, a properly
drained, sound soil will freeze solid and hold its foundations tight. In heaving areas, water sources, the
rate of temperature drop, and certain soil grain sizes can combine to cause pressures on foundations in
all directions. The most important of these three factors is the presence of water in the soil, and this
makes proper drainage a must—for all types of foundations.

Heave Resistance
Most traditional concrete foundations in frost zones rely on depth and gross weight as protections
against frost heave. They use significant volumes of site-poured concrete, which has the potential for
many field condition variables and inconsistent mix designs, and their installation requires considerable
excavation, which weakens the existing soil structure, invites water problems, and leaves substantial
amounts of soil to be removed from a site.
Diamond Pier foundations resist heave pressures and are often used in areas requiring frost protection.
Rather than reaching a specific vertical depth or gross weight, Diamond Pier foundations resist heave
pressures with their wide-spreading pin pile groups. Embedded in the intact soil structure, the pins are
prevented from changing angle under load by the concrete head, creating a stable foundation for both
bearing and uplift forces. Because of the unique design of the Diamond Pier head, the pins are also free
to move along their axes without compromising the position of the head or its lock on the pin cluster.
This feature allows the Diamond Pier foundation to absorb soil strains caused by frost heave or
expansive conditions without losing alignment or transferring these strains to the supported structure.
When assessing projects in extreme frost areas, be aware of sites where traditional concrete footings—
48" to 60" deep—have failed to resist frost heave, requiring larger, deeper concrete piers. Project sites
that require concrete footings deeper than 60" to resist frost heave exceed the definition of normal soil
conditions and the limits of the “Residential Diamond Pier Load Chart.”

Diamond Pier® Installation Manual

7

INSTALLATION INSTRUCTIONS
These instructions only cover the installation of Diamond Pier foundations in residential applications
where normal soil conditions exist and the “Residential Diamond Pier Load Chart” (Table 1) is referenced (see discussion of “Normal Soil Conditions” on page 5 and “Residential Diamond Pier Load
Chart” on page 6).
Please also view the “Installation” video provided on our website, www.diamondpiers.com.

Prior to Installation
Inspect for Underground Obstacles
The same obstacles that conventional foundation systems encounter, such as rocks, tree roots, underground utility lines, and other buried objects, can also obstruct the Diamond Pier system. Refer to
“Encountering Obstructions” (page 13) for instructions on handling buried obstacles. If an obstacle is
encountered that cannot be passed using the breaker hammer while driving the pins and not cracking
the concrete pier head in the process, the pins can be removed and the concrete head rotated, allowing
the pins to penetrate the soil in a different location.

Locate Buried Utilities
WARNING: Do not install Diamond Pier foundations before all underground
utilities have been located, marked, and de-energized.
All underground utility lines must be located and properly marked by your local official utility locating
service, and all privately run lines must also be identified and located by the proper authority. If there are
any electrical lines in the area, de-energize the power source prior to installing the Diamond Pier
foundations. Never allow bodily contact with uninsulated portions of the automatic breaker hammer.
Wear properly rated rubber-insulated gloves and boots. In addition, if underground utilities are located
on the site, check with your local utility locating service to confirm required safety zones. You must
ensure that the horizontal pin distance for your foundation will have adequate horizontal clearance to be
well outside all safety zones, including the 6" Diamond Pier (DP) safety zone (see Figure 2 and Table 2
on next page).

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Figure 2. Horizontal Pin Distance
After installation, horizontal distance of all pins must be well outside all safety zones.

Table 2. Horizontal Pin Distance for All Diamond Pier Models
Measured from center of pier anchor bolt horizontally to vertical limit of pin end.
Horizontal Pin Distance (inches)
Pin Length
(inches)

When Pin Is at 90 degrees
(Perpendicular to Limit Plane)

When Pin Is at 45 degrees
(Shortest Distance to Limit Plane)

36

20

15

42

24

17

50

29

21

63

38

27

84

51

36

126

78

56

Check Your Layout
To meet the load bearing capacities shown in the “Residential Diamond Pier Load Chart” (Table 1, page
6), Diamond Pier foundations must be spaced a minimum of 3 feet apart (from center of pier anchor bolt
to center of pier anchor bolt). If they are spaced less than 3 feet apart, the bearing capacity must be
reduced by 13% for each closer-spaced pier. The piers must also be set back the correct horizontal
distance from existing foundations or other buried obstacles, as shown in Table 2. Tributary loads from
the supported structure must be properly calculated, and the piers spaced accordingly, so that each pier
is supporting only up to its designated allowable loads.

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9

Assemble Tools and Supplies
You will need to assemble the following tools and gear:








Automatic driving hammer with 1-1/8" hex shaft driving bit (see “Breaker Hammers and Driving
Bits,” page 15)
Square-edge shovel
Sledgehammer
Torpedo level
Tape measure
Pipe wrench
Proper protective gear, including safety goggles, ear protection, insulated gloves, protective
clothing, and boots

We recommend a minimum two-person crew for installation.

Inspect and Prepare Diamond Pier Components
Inspect your Diamond Pier assemblies (see Figure 3) to ensure that no parts are flawed or have been
damaged in shipping. Do not install a concrete pier if it has a structural crack with a fissure running
internally into the head (see “Concrete Head Integrity” on page 16). Slight flaking or chipping is
acceptable; a concrete head with surface flaking or chipping may be installed.
Diamond Pier Foundation Components:
 Concrete Head (1) with Anchor Bolt
 Bearing Pins (4)
 Pin Caps (4)
 Inspection Plugs (4)

Figure 3. Diamond Pier Model DP-75/63" – Concrete Head with Bearing Pins
and Package Containing Pin Caps and Inspection Plugs
Verify that you have the correct number of concrete heads with the corresponding number of bearing
pins (4 per pier), pin caps (4 per pier), and inspection plugs (4 per pier), and that the anchor nuts thread
properly on the pier anchor bolts. Measure the pin diameter to be sure the proper pins have been
supplied for your pier model. (The DP-50 model has a 1" nominal pin with a 1.315" actual outside
diameter [OD]; DP-75 has a 1-1/4" nominal pin with a 1.67" actual OD.) If the pins do not fit, contact your
supplier. The inspection plugs are inserted in the bottom of each bearing pin prior to installation to keep
soil from moving up inside the pins as they are driven into the ground. This allows inspectors to slide a
tape measure down a pin from above as a method to verify its length.
Diamond Pier® Installation Manual

10

Install Inspection Plugs in Pins
Remove any dirt and debris from the pins and check
that they will fit easily into the driving holes in the concrete heads. (If a cut or burr is restricting the fit, try the
other end of the pin.)
Install the inspection plugs in the ends of the pins that
will go into the concrete head first. Align the slot in the
plug with the interior weld bead and insert (see Figure
4). The allowable tolerance in pin wall thickness means
that some plugs will fit high in the end of the pin, and
some will fit down almost to the plug shoulder. In either
case, tap the point of the plug with a hammer to seat it
firmly enough in the end of the pin so that it will not drop
out as you slide it through the driving holes in the pier.
Don’t worry that tapping the end of the plug with the
hammer will blunt the point; it is not intended as a
piercing or cutting tip, and this will happen anyway as
the plug is driven into the soil. (See “Encountering
Obstructions,” page 13, for plug use where buried obstructions may be encountered.)

Point

Shoulder
Slot
Plug Sits
Low in
Pin

Plug Sits
High in
Pin

Thick
Wall Pin

Thin
Wall Pin

Figure 4. Inspection Plugs
Must Be Installed in Pins

Installation
Identify and Mark Location
1. Identify where you would like the center of the pier anchor bolt to be located.
2. Mark the location by using reference points that will easily identify the center location of the pier
even after top soil is removed. Tip: Set a string line centered on the anchor bolt approximately
12-14" above the ground for a quick reference point and to maintain alignment.

Set the Concrete Head
1. Dig a tapered square hole the same size and shape
as the bottom half of the concrete head (see Figure 5).
This creates a cradle to steady the head for leveling.
Soils directly below the head should be left loose.
2. Following safe lifting procedures, carefully lift the concrete head and position it in the hole to its midpoint.*
Ensure top is level and centered on your alignment.
3. Replace some of the removed soils back around the
sides of the head at grade, lightly tamping to maintain
level and alignment during pin driving. (See Notes
under “Drive in the Pins” on page 12.) A few inches of
small rounded pea gravel may be used if native soils
are not available.

Figure 5. Tapered Hole for
Concrete Head

NOTE: The edges of the top of the concrete head do not have to align exactly with the sides of the
post or post bracket as long as the bracket being used is fully supported by the concrete and
providing proper weight distribution.
*The concrete head may also be buried for aesthetic considerations, but access to the top of the head needs to
be maintained. Concrete slabs, patios, and other products installed MUST NOT interfere with the Diamond Pier
foundation and the attached post/beam assembly. Expansion joints may be used to protect the foundation.
Proper drainage must also be maintained.

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11

Drive in the Pins
WARNING: Verify locations of any buried utilities before driving pins (see “Locate
Buried Utilities,” page 8).
1. Slide the ends of the pins with the inspection plugs
through opposing holes in the concrete head,
making sure to support them so their weight does
not roll the head out of the hole or out of alignment.
2. Keeping the pin centered in the driving hole, carefully set each pin 6" to 12" into the soil tapping with
the sledgehammer (gripped just below the hammer
head) until the concrete head is locked into a level
position (see Figure 6). Impact the pin end squarely
to minimize flaking of the concrete surface or
deformation of the end of the pin (see Note 1).
3. With the pin driving bit installed on the automatic
hammer, and another crew member holding the pin,
Figure 6. Setting Pins and
drive in opposing pins alternately in increments
Leveling Concrete Head
(see Note 2). Periodically check for alignment and
level (a 5-degree tolerance is allowed). Be sure to keep the weight of the auto-hammer from
forcing the pin against the lower half of the driving hole and impacting the concrete head. The
other crew member should hold the pin centered in the driving hole (see Figure 7). This will also
reduce pin vibration and minimize concrete flaking.
NOTE: Do not use the pin driving bit as a hammering tool or hammer against it with the
sledgehammer. It is to be used with the automatic hammer only.

4. Temporarily drive all pins down to within 6" from the
top of the head; this allows easier removal if an
obstruction is encountered (see Note 3).
5. Finish driving the pins with the automatic hammer
(with pin driving bit), being careful not to damage
the precast concrete head or the upper ends of the
pins and leaving approximately 3/4" of the pin
protruding from the top of the concrete.
Note 1: Do not attempt to drive the pins all the way
down with just the sledgehammer; this may damage the
ends of the pins or crack the concrete head.
Note 2: Do not drive a pin all the way down at once as
this may cause the head to be pulled to one side.
Continue to rotate around the head, driving the pins in
increments, until the growing strength in the pile group
is sufficient to allow final driving.

Figure 7. Driving Pins with
Note 3: Do not continue to hammer away at a pin that
Auto-hammer and Pin Driving Bit
is bouncing, rattling, or scraping against an impassable
object. This may cause the concrete head to ride up the pin, push the head to one side, or risk
eccentrically stressing the head with a pin that is out of line. It could also cause the concrete head to
have a structural crack, which would require removal and replacement (see “Concrete Head
Integrity” on page 16). If encountering difficulties in the soil, see “Encountering Obstructions” on the
next page.

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Encountering Obstructions
If a pin stops moving when being driven in, STOP driving the pin. If the obstruction is close enough
to the surface, it may be dug up and removed. Once accomplished, recompact the soils with the
sledgehammer, and then reset the concrete head.
You can also try to drive the pin past or through the obstruction. Be sure the other pins are at least
half way in to stabilize the concrete head and ensure that the head will remain in place before trying
to drive the obstructed pin in any further. Put a pencil mark on the pin by the head to indicate if the
pin moves. Attempt to drive the obstructed pin with the automatic hammer for approximately 10 to 20
seconds, or give it one or two firm square hits with the sledgehammer, which may drive it past the
obstruction. Many small rocks will roll, potentially allowing the pin to move directly past. If the pin
begins to move, continue with the automatic hammer, but make sure that it is not being forced out of
line. If its trajectory is off, this can cause an eccentric stress on the concrete head and crack it.
If you can remove the pin, you can try removing the soil plug and redriving. Inspection plugs may
only be omitted when approved by the building official. With the plug removed and less surface area
at the lower end, the pin may drive easier, and not be forced by the angle of the plug past an
obstruction, but off its trajectory.
If the trajectory is off or the pin will not go in at all, remove all the pins (see “Removing Pins”), rotate
the concrete head around its center alignment, and reinstall to avoid the obstruction. The pier may
also be relocated, within the parameters of your structure’s design, if necessary.

Removing Pins
The jacking method is used to spin and pry a pin out from the concrete head simultaneously by
using a pipe wrench and a pry bar. This method works best when the pin is approximately 6"
extended out from the concrete head. A pipe wrench, a flat bar, and a pry bar are required. Follow
the instructions below to turn the pin while corkscrewing it upward. See also the “Pin Removal” video
on the website.
1. Using your right hand, place the pry bar flat against
the concrete angle at the outer edge of the pier head
and perpendicular to the pin to be removed.
2. With your left hand, place the pipe wrench on the pin
and slide it down tight to the pry bar. The pipe
wrench handle should be pointing up slightly and
perpendicular to the pry bar to allow the pipe wrench
to turn the pin as it is pried (see Figure 8).
3. Pull up on the pipe wrench handle to lock.
4. Pull up on the pry bar with your right hand to move
the pin out approximately 1" to 2".
5. Slide the pry bar back to be flush with the concrete
angle on the pier head.
6. Repeat lock and jack (steps 3–5) until the pin can be
pulled out by hand.

Figure 8. Jacking Method for
Pin Removal

Note 1: For the first 4" of removal use the flat bar with the pipe wrench. After the pin is 4" removed
you may use a pin as a pry bar.
Note 2: For an alternate removal technique, an internal pipe locking tool with an electric impact
wrench may be used to spin the pin and draw it from the concrete head.

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13

Place Pin Caps on Pins
1. Set the pin caps loosely on the ends of the pins so
they can be removed for pin length inspection (see
“Pin Length Inspection,” page 16).
2. Set brackets and posts or beams, and frame and
complete the supported structure.
3. Once these framing material loads have been applied, pull the caps off and reverify the extent of the
protruding pins, adjusting as necessary by tapping
with the small sledgehammer.
4. After the field inspection has been completed, tap
the caps down tight with the small hammer (see
Figure 9) to seal them against the concrete.

Figure 9. Completed Installation
with Pin Caps
NOTE: If the caps will not go on, check the pin ends for any extreme deformations that may have
occurred while driving. File or grind off any damage to re-establish the original diameter, and apply
the cap.

Register Your Product Warranty
1. Download the Limited Lifetime Warranty Application Form available at www.diamondpiers.com.
2. Submit application within 30 days of project completion.
3. Confirm receipt of your registered warranty by PFI.

Diamond Pier® Installation Manual

14

AUXILIARY PARTS AND EQUIPMENT
Post/Beam Brackets
The bracket needed to make the connection from the Diamond Pier foundation to the superstructure can
be purchased separately from a local lumberyard. The DP-50 pier typically has a 1/2" diameter
galvanized bolt embedded in the top of the concrete head (nut provided), and this bolt will connect to a
code-approved post base. The DP-75 pier has a 5/8" diameter bolt at the top of the concrete head.
Check your local building code or building official to verify which post bases are acceptable in your area,
and make sure to match the post size and loads on the post with the appropriate bracket size and
bracket load ratings. Typically these brackets come with a “standoff” design that separates the wood
from contact with the base of the bracket and eliminates the need to drill into the bottom of the lumber to
compensate for the raised anchor bolt. Most post-base brackets have a wide hole in the base that allows
for horizontal adjustment of the final bracket location.
Horizontal beams may also be set directly in an appropriate bracket for direct connection to the Diamond
Pier foundation when constructing low-profile structures. Larger piers not shown on the “Residential
Diamond Pier Load Chart” (Table 1) have a variety of bolt diameters and configurations. Contact PFI for
more information if your project requires piers larger than the DP-50 or DP-75.
The proper bracket coating or finish should be chosen based on the lumber to be used and the treating
specifications of the project superstructure. If stainless steel is chosen, the embedded galvanized bolt
must be protected from contact with the stainless bracket with the addition of a plastic or rubber bushing
(not supplied) or the concrete heads must be special ordered with embedded stainless steel anchor
bolts to avoid the potential for corrosion of dissimilar metals in contact.

Breaker Hammers and Driving Bits
The Diamond Pier driving bit is recommended for use with a standard breaker/demolition hammer, see
below. The driving bit has a 1-1/8" hex shaft, and can be rented or purchased through a local dealer or
purchased directly from PFI. NOTE: The bits are NOT to be used with, or as, a sledgehammer.
Only automatic breaker/demolition hammers should be used to install the Diamond Pier pins. Any
standard automatic hammer that will handle a 1-1/8" hex shaft can be used, provided it can be properly
and safely controlled by the operator and not risk injury or damage to the concrete head. Soft or loose
soils will allow for the use of lighter lower-energy hammers. Stiff or dense soils will require electric
hammers in the higher impact range or standard jackhammers driven by compressed air. In most cases,
the DP-50 and DP-75 are installed with electric hammers. Roto-hammers are not adequate.
Below is a list of commonly available electric automatic breaker/demolition hammers.






BOSCH Brute #BH2760VC
MAKITA Model #HM1307CB
HITACHI Model #H65SD2
BOSCH Model #11335K
MILWAUKEE Model #5338

Diamond Pier® Installation Manual

63-lb Breaker Hammer; Bit type: 1-1/8" Hex
35-lb Demolition Hammer; Bit type: 1-1/8" Hex
40-lb Demolition Hammer; Bit type: 1-1/8" Hex
35-lb Breaker Hammer; Bit type: 1-1/8" Hex
71-lb Breaker Hammer; Bit type: 1-1/8" Hex

15

FIELD INSPECTION
A Diamond Pier foundation code inspection may take place at any time during or after installation and
may be combined with the structural framing inspection as each jurisdiction warrants. The top ends of all
pins should be accessible for measuring pin lengths.

Pin Length Inspection
Diamond Pier foundations are designed to be inspected from above grade after they have been
installed. An inspection plug must be installed at the lower (driven) end of the pin to keep soils from
moving up inside it and to allow a tape measure to be slid down from the top of the installed pin to verify
its length (see “Install Inspection Plugs in Pins” on page 11).
NOTE: The Diamond Pier foundation is a shallow bearing technology and does not require “refusal” or
“friction” resistance, or the professional installation monitoring or special inspection typically associated
with conventional vertical or battered piling.
NOTE: If framing members will be too close to the top of the concrete head to allow the tape measure to
be inserted, then the inspection should be done before the framing is in place. Also, if inspection plugs
have been unintentionally forgotten, then the pins can be twisted or jacked out with a pipe wrench to
verify their length (see “Removing Pins” on page 13). They can then be redriven into the same soil
cavity. If a plug has been removed to facilitate driving in an obstructed condition (see “Encountering
Obstructions,” page 13), be sure to note or mark the location of this pin for the inspector. Pins are to be
their full specified length without joints or coupling (length tolerance is ±1/2").

Pin Specifications
Bearing pins provided with the piers are schedule 40 galvanized pipe, Grade A electric resistance
welded, with no threads. This also can be verified from above grade; with the pin cap removed, the weld
can be verified on the inside wall of the pin, and the wall thickness can be checked. If the wall thickness
is thinner than specified, the pins have been substituted with a lower schedule pipe or conduit and must
be replaced with the properly specified pipe—1" nominal schedule 40 pipe has a wall thickness of 0.133"
(just over 1/8"), 1-1/4" nominal schedule 40 pipe has a wall thickness of 0.140". The wall thickness
tolerance is ±12%.

Concrete Head Integrity
If the “INSTALLATION INSTRUCTIONS” (page 8) are properly followed, the concrete heads should be
level, and they should not have structural cracks as a result of improper handling or pin driving. (Surface
spalls or chips may occur during driving or handling, but these are not structural, and will not affect the
concrete head.) A structural crack is a fissure running internally into the head. It is perpendicular to the
outer face of the head and runs inward to its core. This can weaken the strength of the pier head and/or
allow water to penetrate and cause freeze/thaw problems in the concrete. If a concrete head has a
structural crack, it should NOT be patched. It must be removed and replaced.
If a concrete head is more than 5 degrees out of level, the symmetry of the pin pairs may be compromised, and the head should be removed and correctly reinstalled.

Diamond Pier® Installation Manual

16

Allowable Capacity
The piers must not be overloaded. The total load on any specific pier is based on the individual tributary
loads of the structure, supported by the corresponding post or beam connected to the pier. If you are not
capable of properly calculating allowable loads, have the loading and capacities verified by your local
building department or an independent registered design professional.
The total load calculated for a post or beam connected to the pier (also known as the “support column”)
is based on a combination of the live load (snow, people, furnishings, etc.) and the dead load (weight of
structure itself). The live load and dead load requirements are provided by your local bulding department; loads are specified in pounds per square foot (psf). A determination must be made as to what
portion of the floor area is supported by a single support column. A design professional should be able to
make this determination. Once the proper area for the single support column is determined, multiply the
area (A) supported by the required loads (in psf) to determine the total tributary load (in pounds) for the
single pier:
(A) x (psf) = Total Tributary Load
This value should not exceed the published capacity of the Diamond Pier model and corresponding pin
length intended for use.

Diamond Pier® Installation Manual

17

SPECIFICATIONS
The information given in this section is provided for use in document/permit submittal, where applicable.

References/Standards
ASTM A 53 - Pipe, Steel, Black and Hot dipped, Zinc-coated
ASTM A153 - Zinc coating (hot-dip) on Steel Hardware
ASTM, ACI, and CRSI standards for precast concrete products

Delivery/Storage and Handling
Contractor shall protect the materials from damage.

Pins
Four pins per pier. All pins to be galvanized steel pipe with butt cut ends, schedule 40, Grade A, Type E,
electric resistance welded. Pins are to be capped with UV-resistant vinyl caps.

Connections/Posts/Beams
Diamond Pier foundation connection to be galvanized steel post base or beam bracket (by others)
attached to embedded single galvanized anchor bolt in concrete head. See “Post/Beam Brackets”
(page 15).

Site
Alteration of site soils or vegetation to be kept to a minimum to avoid erosion, drainage issues, or the
need for replanting. Site must be properly drained.

Installation
Contractor shall verify superstructure layout, spans, and resulting loads for consistency with the manufacturer’s published capacities.
Pins to be full length as specified before driving. No coupled or welded pins are to be used.
Follow the complete Installation Instructions provided in this manual.

Diamond Pier® Installation Manual

18

TROUBLESHOOTING
Cracked Concrete
Head

Always inspect materials when received from supplier. Do not install a head that
has a structural crack or fissure running internally into it. Slight flaking or
chipping does not constitute a crack.

Concrete Flaking

During installation, pins rubbing against the concrete head may cause superficial
flaking of concrete around the driving hole. This will not affect the structural
strength. However, if a structural crack or fissure running internally into the
concrete head develops during installation, the integrity of the pier has been
compromised and the concrete head must be removed and replaced.

Concrete Head Will
Not Stay Level When
Installing

One or more pins may be driving out of line due to obstructions in the soil (See
“Encountering Obstructions,” page 13), or your hole for setting the concrete
head may be too big. Only dig a hole the size of the head being used, and be
sure to put all pins in the head before setting them. With all the pins sticking up
from the head, one person can also push or pull on the pins to manipulate the
leveling process and guide or steer the concrete head to a level position, being
careful not to wrench on it and cause a crack.

Concrete Head
Installed Out of Level

If a concrete head is more than 5 degrees out of level, the symmetry of the
bearing pins may be compromised—the head should be removed and
repositioned. Reinstall the pins incrementally at first, checking level constantly,
and if one pin is not going in straight and is causing the head to tip, install the
other pins first and then carefully finish driving this last pin.

Hitting an Obstruction
When Installing

If an obstruction is encountered, the pins may be removed and the concrete
head repositioned. If the obstruction is dug out and removed, soil must be
recompacted per the Installation Instructions. See “Encountering Obstructions”
(page 13).

Installing in Frozen
Ground

Check with the local building code for criteria or limitations on installing foundations in frozen soil. See “Frost Heave” and “Heave Resistance” on page 7.

Pins Have Risen
Slightly Out of the
Concrete Head

This may occur when extreme loads have been applied to the pier, but the
foundation is designed to relieve pressure in this way. The pins may simply be
tapped back to their original position with a small hammer. Remove the caps,
tap the pin, and replace the caps.

Pins Will Not Fit into
Concrete Head

Make sure the pins fit into the concrete head before inserting the inspection
plugs. Be sure pins and concrete heads are free of dirt, and check both ends of
pins for fit. Always transport and store parts in a clean environment. Measure
the pin diameter to be sure the proper pins have been supplied for your pier
model. (The DP-50 model has a 1" nominal pin with a 1.315" actual outside
diameter [OD]; DP-75 has a 1-1/4" nominal pin with a 1.67" actual OD.) If the
pins still do not fit, contact your supplier.

Pin Caps Will Not Fit
over Driven Pins

Check to be sure the proper cap size was supplied and that your caps are
pliable and not frozen. Caps should be tapped on with a small hammer. If they
still will not go on, check the pin ends for any extreme deformations that may
have occurred while driving. File or grind off any damage to re-establish the
original diameter, and apply the cap.

Diamond Pier® Installation Manual

19

Pin Foundations, Inc.
Gig Harbor, Washington

Toll Free: 866-255-9478 / Main Office: 253-858-8809
www.pinfoundations.com or www.diamondpiers.com
© 2018 by Pin Foundations, Inc. All rights reserved. DOC0007/01.2018



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Title                           : DP Installation Manual                                                                                                                      10/28/96
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