Hydrostop Premium Coat Liquid Applied Roofing Manual

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Version 1.2

HYDROSTOP

PREMIUMCOAT
LIQUID-APPLIED
ROOFING
®

Application &
Specifications
Manual

gaf.com

HydroStop® PremiumCoat®

Liquid-Applied Roofing Application & Specifications Manual
Table of Contents
Welcome...............................................................................................................................................3

Section 1: Guides
Product Guide......................................................................................................................................6
Cleaner & Primer Guide........................................................................................................................7
Seam Treatment Guide.........................................................................................................................8
Warranty Guide.....................................................................................................................................9

Section 2: Substrate Preparation
General Substrate Conditions.............................................................................................................11
Moisture Survey.................................................................................................................................12
Repair
Damaged Substrate Treatment: Metal.....................................................................................13
Damaged Substrate Treatment: Non-Metal............................................................................14
Cleaning Procedures
Treatment..............................................................................................................................16
General Substrate Preparation
Metal.......................................................................................................................................17
TPO.........................................................................................................................................20
PVC & Hypalon®......................................................................................................................21
EPDM......................................................................................................................................22
Smooth & Granulated Asphaltic..............................................................................................23
Structural Concrete..................................................................................................................24
Adhesion Testing
Test Method #1: Test Patches..................................................................................................25
Test Method #2: Field Peel Adhesion (Alternate to Test Patches)...........................................26

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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Substrate
Conditions

Section 3: Quick Spec Directory
HydroStop® PremiumCoat®..............................................................................................................28
Metal.......................................................................................................................................29
Smooth & Granulated Asphaltic.............................................................................................30
TPO........................................................................................................................................31
PVC........................................................................................................................................32
Hypalon®................................................................................................................................33
EPDM......................................................................................................................................34
Structural Concrete.................................................................................................................35
Corrugated Structural Transite Panels....................................................................................36
Polyisocyanurate (ISO)..........................................................................................................37
Gypsum (DensDeck & SecuRock)...........................................................................................38
Warranty Extension/Renewal.................................................................................................39

Section 4: Care & Preventative Maintenance
Overview............................................................................................................................................41
General Care & Preventative Maintenance Recommendations.......................................................41
Semi-Annual Inspections & Maintenance.........................................................................................43
Inspection Checklist...........................................................................................................................45
Roof Specific Leak Investigation........................................................................................................46
Emergency Repairs.............................................................................................................................46
Roof Alterations.................................................................................................................................47

Section 5: Architectural Detail Drawings
HydroStop® PremiumCoat®...............................................................................................................49
HS-101 Typical Metal Roof Joint Detail....................................................................................50
HS-102 Section at Vertical Panel Seam...................................................................................51
HS-104 Deck Joint Stripping Detail..........................................................................................52
HS-201 Standard Drip Edge Detail...........................................................................................53
HS-202 Gutter with Standard Drip Edge Detail........................................................................54
HS-203 Concrete Roof Deck Edge Detail..................................................................................55
HS-300 Alternate Wall Flashing Detail....................................................................................56
HS-301 Wall Flashing Detail.....................................................................................................57
HS-302 Drip Edge Parapet Wall Detail.....................................................................................58
HS-303 Typical Roof Cant At Corner........................................................................................59
HS-304 Typical Equipment Curb Flashing Detail.....................................................................60
HS-305 Scupper Detail.............................................................................................................61
HS-401 Curb to Curb Expansion Joint Flashing Detail.............................................................62
HS-502 Vent-Pipe Flashing Detail............................................................................................63
HS-503 Vent-Stack Flashing Detail...........................................................................................64
HS-504 Standard Roof Drain Detail..........................................................................................65
HS-505 Exhaust Fan (for Cooking) Flashing Detail...................................................................66

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ABOUT GAF
As North America’s largest roofing manufacturer, GAF proudly offers a comprehensive portfolio of
award-winning, innovative roofing products for both residential and commercial properties. Supported
by an extensive national network of factory-certified contractors, GAF has built its reputation—and its
success—on its steadfast commitment to Advanced Quality, Industry Expertise, and Solutions Made
Simple.
GAF offers all major low-slope roofing technologies, including repair and maintenance products and
roof restoration systems, as well as new roofing systems (BUR, modified bitumen, TPO, PVC, and
liquid-applied systems). GAF has developed low slope roofing systems with excellent durability and
high reflectivity to meet the most rigorous industry standards while helping commercial property
owners and designers reduce energy consumption.
For more information about GAF, visit us at www.gaf.com.

SERVICES
• Every GAF roofing product benefits from the substantial resources available only from a
multibillion-dollar corporation dedicated to roofing. Our 31 plants mean manufacturing
expertise. Our extensive R&D organization means a constant focus on product and process
improvement. GAF is a team of over 3,000 people dedicated to your roofing satisfaction.
• GAF has a network of sales representatives and distributors to supply and service its quality
roofing systems throughout North America.
• Our Technical Helpline is a technical assistance service that allows you to contact us directly to
speak with a technical representative about specifications, applications, code approvals, and
product information. The Helpline number is 1-800-ROOF-411 (1-800-766-3411).
• Architectural Information Services (AIS) is a specification service that allows you to specify your
exact roofing needs and we will send you a general specification that outlines your job summary,
application method, product description, and detail drawings based on the information you
provided. The phone number for AIS is 1-800-522-9224.
• Our Tapered Design Group (TDG) is one of the many services available to our customers to help
reduce their hassles. We provide tapered insulation take-offs for architects, contractors, and
distributors nationwide. Just send your roof plans and specifications to tdg@gaf.com. The phone
number for TDG is 1-800-766-3411.
• Visit GAF on the web at www.gaf.com for extensive product information, specifications, and
technical literature.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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Welcome

Thank you for consulting Version 1.2 of the HydroStop® PremiumCoat® Liquid-Applied Roofing
Application & Specifications Manual. This Manual contains the latest information relating to the
application of GAF’s HydroStop® PremiumCoat® liquid-applied roofing systems, and is based on our
years of experience in the commercial roofing field. It has been prepared as a general guide to assist
architects, engineers, roofing contractors, and owners in the use of our liquid-applied roofing systems.
You can find further information at www.gaf.com, or contact GAF Technical Services at 1-800-ROOF411 (1-800-766-3411).

Welcome

DISCLAIMER
• GAF manufactures and sells roofing materials and does NOT practice architecture or
engineering. GAF is NOT responsible for the performance of its products when damage to its
products is caused by such things as improper building design, construction flaws, or defects in
workmanship.
• The design responsibility remains with the architect, engineer, roofing contractor, or owner, and
construction details illustrated and described herein are furnished solely for guidance purposes.
These guidelines should not be construed as being all-inclusive, nor should they be considered as
a substitute for good application practices.
• Under no circumstances does GAF have any liability for costs or expenses arising out of or
associated with the pre-existing presence of asbestos-containing materials or any other allegedly
hazardous substances or materials on the roof to which the new GAF roofing materials are being
applied.
• Information contained in this Manual is presented in good faith and, to the best of GAF’s
knowledge, does not infringe upon any patents, foreign or domestic.
• As a part of its continuing efforts to improve the performance of its products, GAF periodically
makes changes to its products and application specifications. GAF reserves the right to change
or modify, at its discretion, any of the information, requirements, specifications, or policies
contained herein. This Manual supersedes all catalogs and previous Manuals.

GENERAL DESIGN CONSIDERATIONS
HOW TO DETERMINE IF A ROOF IS A GOOD CANDIDATE FOR COATING
When installed on a new roof, a roof coating should:
•B
e a component part of the larger warranted roofing system. This will ensure compatibility with the
system and enhance overall performance of the system.
•B
e installed after the roof has weathered as necessary. Weathering periods may vary depending
upon the type of system to which the coating will be applied. Use of a primer may also be required
for certain substrates to ensure adequate adhesion.
When installed on an existing roof, a roof coating should:
•B
e compatible with the existing roof.
• E xtend the remaining service life of the existing roof. Although a coating cannot add life back to a
roof already beyond its service life, it can prevent a roof from aging as quickly as it would without
the coating.
•O
nly be applied to a roof that drains properly. Some coatings may be adversely affected by the
presence of ponding water. Therefore, areas of the existing roof that pond water should be
repaired prior to coating.
•O
nly be applied to non-leaking roofs. While coatings may help seal some pinhole leaks not visible to
the naked eye, they will not generally find and repair existing leaks. Accordingly, existing roof leaks
will need to be identified and repaired prior to coating. (Allow repairs to fully dry prior to coating.)
NOTE: When coating over an existing roof coating or an existing coal tar pitch roof, contact GAF
Technical Services at 1-800-ROOF-411 (1-800-766-3411).

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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Guides

Section 1
Guides

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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Type

Primers & Cleaner

Roof
Coatings

Flashing, Sealants &
Accessories

Self‐Adhering Butyl Non‐Woven Polyethylene Seam Tape

United Coatings™ UniTape Seam Tape

Elastomeric Sealant

FlexSeal™ Caulk Grade Sealant

Glass Fiber Bulking Agent

Water‐Based Acrylic Base Coat

HydroStop® PremiumCoat® Foundation Coat

HydroStop® Hydrofiber Bulking Agent

Water‐Based Acrylic Top Coat

HydroStop® PremiumCoat®Finish Coat

Self‐Adhering Butyl Aluminum Caps For Fasteners

Primer For Concrete and Waterproofing

HydroStop® BarrierGuard® Waterproofing

United Coatings™ UniCap Fastener Cover

Water‐Based Roof, Wall and Deck Surface Cleaner

United Cleaning Concentrate (UCC)

Stitch‐Bonded Polyester Reinforcement

Water‐Based Acrylic Primer For Kynar Coated Metal

HydroStop® PremiumCoat® Fabric

Water‐Based Acrylic Penetrating Primer And Asphalt Bleed Blocker

UniBase Primer
XR‐2000 Primer

Water‐Based Acrylic Flashing

Solvent‐Based Primer For TPO Roofs

TPO Red Primer

Self‐Leveling Elastomeric Sealant

Water‐Based

Water‐Based Acrylic Primer For Chalky Surfaces

SureBond Primer

FlexSeal™ Sealant

Solvent‐Based

Water‐Based Acrylic Rust‐Inhibiting Primer

StableRust Primer

HydroStop® PremiumCoat® Butter Grade Flashing

Moisture‐Cure

Moisture‐Cure Urethane Primer For Corrosion Protection On Metal
Surfaces

Lock‐Down Primer

n/a

Water‐Based

Solvent‐Based

Water‐Based

Water‐Based Rinsable Primer For EPDM

Water‐Based

Water‐Based Epoxy Primer For Concrete and Porous Substrates

Water‐Based Rinsable Primer For EPDM

Adhere‐It® II Primer

Water‐Based

CleanAct Rinsable Primer

Water‐Based Acrylic Rust‐Inhibiting Primer For Metal

Acrylex 400 Primer

Base/Cure

Epoxy Primer (formerly Uniseal Primer)

Description

Product

Product Guide

n/a

<50

<300

<50

n/a

< 170

<50

<200

<420

<120

n/a

<50

VOC
(g/L)

Guides

n/a

% Solids by
Volume

Cleaner & Primer Guide
Cleaner*

Single-Ply

Asphaltic
(BUR, SBS,
APP)

Metal

Rusty Metal

Application Rates

Acrylex 400

0.33-0.67 gal /100 sf
(1.4-2.7 L / 10 sq m)

or StableRust

0.33-0.50 gal / 100 sf
(1.4-2 L / 10 sq m)

YES

Severe Rusty Metal

YES

Lock-Down Primer

0.25 gal /100 sf
(1 L / 10 sq m)

Kynar Coated Metal

YES

XR-2000

0.75 gal /100 sf
(3.1 L / 10 sq m)

Residual Asphalt

YES

UniBase

0.50-1.0 gal /100sf
(2-4 L / 10 sq m)

Smooth Asphaltic

YES

UniBase

0.50-1.0 gal /100sf
(2-4 L / 10 sq m)

Granulated Asphaltic

YES

UniBase

0.50-1.0 gal /100sf
(2-4 L / 10 sq m)

TPO (new or aged)

YES

TPO Red Primer

0.50 gal/100 sf
(2 L / 10 sq m)

PVC (aged)

YES

No Primer

n/a

Hypalon (aged)

YES

No Primer

n/a

EPDM

Adhere-It II
(or CleanAct)

0.2 gal/100sf
(0.8 L / sq m)

Epoxy Primer

0.33 gal/sq
(1.4 L/10 m2)

or BarrierGuard

0.5-1.0 gal/sq;
(1.9 L-3.8 L/10 m2)

Structural Concrete
Other

Primer

YES

Gypsum (DensDeck & SecuRock)

No Primer

n/a

Polyisocyanurate (ISO)

No Primer

n/a

Existing Acrylic Coating

YES

No Primer

n/a

Corrugated Structural
Transite Panels

YES

Epoxy Primer

0.33 gal/sq
(1.4 L/10 m2)

*United Cleaning Concentrate required
NOTE: Existing silicone coating is not an acceptable substrate for HydroStop® PremiumCoat®.

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Guides

Substrate

Seam Treatment Guide
Guides

Substrate

Treatment
Ribbed Seam
Standing Seam
Standing “T” Seam

Vertical Seams
Metal

Inverted “J” Seam

Butter Grade Flashing

Corrugated Seam

Re-Cover
Assemblies

Other

Asphaltic
(if loose or split)

Single-Ply
(if loose or split)

Batten Seam
Horizontal Seams

Butter Grade w/Fabric or
Foundation Coat w/Fabric

TPO

No Treatment

PVC

No Treatment

Hypalon

No Treatment

EPDM

No Treatment

Smooth Asphaltic

No Treatment

Granulated Asphaltic

No Treatment

Structural Concrete
(non-structural cracks)

No Treatment

Polyisocyanurate (ISO)

Butter Grade w/Fabric or
Foundation Coat w/Fabric

Gypsum (DensDeck & SecuRock)

Butter Grade w/Fabric or
Foundation Coat w/Fabric

Corrugated Structural Transite Panels

No Treatment

Contact GAF Technical Services at 1-800-766-3411

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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Warranty Guide
Emerald Pledge™
15 yr

20 yr

10 yr

15 yr

20 yr

HYDROSTOP: Who can offer Warranty?
No

Authorized Contractors
Master & Master Select Contractors

Yes

No
No

Yes

Pre-Inspection/Approval

Yes, for jobs over 20,000 sq. ft.
(1,858 sq m)

Interim Inspection

Yes, for jobs over 10,000 sq. ft.
(929 sq m)

Yes

Final Inspection

Yes

Maintenance Program

Yes

Premium Contractors
Requirements
Moisture Survey for non-metal roofs

Transferable

Yes

Warranty Registration

Yes

Coverage
Manufacturing Defects

Yes

Ordinary Wear & Tear

Yes

Workmanship

Yes

Materials

Yes

Labor

Yes

Remedy

NOTES:
1. Liquid-Applied Emerald Pledge™ and Diamond Pledge™ must be applied per specifications.
2. Pre-Approval required for all 20 year Warranties by Director or above (Sales or Field Services).

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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Guides

10 yr

Diamond Pledge™

Substrate
Conditions

Section 2
Substrate Preparation

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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GENERAL SUBSTRATE CONDITIONS

Always contact GAF’s Technical Services Department (800-766-3411) for questions regarding suitable
substrates, materials for test patches, or if you require additional information.
PROPER PREPARATION FOR ROOF TYPES
To ensure proper coating application, the existing roof membrane must be thoroughly cleaned. All
dust, chalking film, bitumen exudate, greases or oils, and other loose debris should be removed
prior to coating. Be careful when pressure washing to preserve the integrity of the existing roof
membrane and to avoid damage to membrane seams (especially adhered seams). Allow the roof to
dry completely prior to coating. Any required roof or flashing repairs should be completed and allowed
to adequately cure where necessary. Refer to specific sections of this Manual for more information on
roof preparation.
Depending on type of existing substrate and the coating to be applied, use of a primer may be
required. Surfaces which typically require primer include: metal flashings, gravel stops, and other
metal edging; concrete roof decks, masonry walls and other floor surfaces, and other porous surfaces.
Refer to specific sections of this Manual for detailed requirements.
While rusted metal roofs can be coated, additional measures may be required. If the roof is affected by
“white rust” (i.e., zinc or aluminum), it can be coated after cleaning. However, if the roof is affected by
“red rust,” the rust must either be removed or treated with corrosion inhibiting primer. Additionally, all
rusted fasteners should also be removed or treated with a corrosion inhibiting primer.
WHAT IS BENEATH THE EXISTING ROOF SURFACE?
In membrane roof systems, there is typically a layer of insulation beneath the membrane. If the
roof has ever experienced leaks, it is possible that there are areas of wet insulation in the existing
roofing system. All wet roof insulation must be removed and replaced prior to coating. While certain
areas of wet insulation may be noticeable simply by walking on them, an infrared moisture scan is
recommended to more accurately determine areas of wet insulation.
Metal roofs are typically installed over a solid roof deck or over purlins and insulation. Examining the
underside of the roof deck can reveal areas of wet insulation, deteriorated deck or other damage that
needs to be repaired prior to coating.
HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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Substrate
Conditions

Preparation of the roof substrate is the responsibility of the installer, who must address and correct all
of the conditions listed in this section.
• Examine substrates to receive new roofing. If any questions arise regarding the compatibility of
HydroStop® PremiumCoat® liquid-applied roofing products with an existing substrate, Installer
shall prepare test patches to check adhesion.
• Do not proceed with the installation of the HydroStop® PremiumCoat® liquid-applied roofing
system until compatibility and adhesion of HydroStop® PremiumCoat® roofing system has been
verified by test patches and other preparatory work has been completed and unsatisfactory
conditions have been corrected.
• Roof must have positive drainage. Substrate should not pond water for more than 48 hours after
precipitation stops.
• GAF defines “ponding” as water that does not drain or dissipate from the roof surface within
48 hours after precipitation ends. Ponding can also result from other water sources, including
improperly piped air conditioning condensate and steam condensate lines.
• Protect adjacent surfaces that will not be coated.
• Do not apply liquid-applied roofing products to surfaces unacceptable to GAF, or under inclement
environmental conditions.
• Substrates must be clean, completely dry, and free of any debris before application of any liquidapplied products.
• HydroStop® PremiumCoat® liquid-applied roofing products should not be used on heavy-traffic
bearing substrates. If foot traffic is expected, a rooftop walkway system approved by GAF must be
used.

Substrate
Conditions

MOISTURE SURVEY
It is the responsibility of the roofing contractor to determine the suitability of any substrate to
receive a liquid-applied coating system. Roof moisture surveys are a common tool used to assist with
this determination. When the deck/substrate has more potential to “hold” water, a moisture survey
may be required by GAF.
Alternately, for decks/substrates such as steel, the use of roof cuts to verify the suitability of the
substrate can be effective.
Where a moisture survey is performed:
•
•
•

GAF requires a moisture survey be conducted by the roofing contractor prior to warranty
issuance for Emerald Pledge™ and Diamond Pledge™ Guaranteed Systems installed over existing
roofs.
If the moisture survey shows areas of the roof that are wet, remove and replace all wet areas
with new materials. Make typical repairs with original roof technology and follow the appropriate
surface preparation steps.
Moisture surveys include: IR scans, nuclear scans, test/core cuts, and portable devices used to
indicate moisture.

Liquid-Applied Roofing Systems
Roof Moisture Survey Criteria
Emerald™ Pledge & Diamond Pledge™ Guaranteed Systems
Project Size

Less than 100 Sqs. (929 sq m)

Roof Survey Criteria

Roof Surveys Recommended

Deck/Substrate
(non-standing seam metal†)

All*

100 Sqs. (929 sq m) or Greater
Roof Surveys Recommended

• Steel*
• Wood*
• Cementitious Wood Fiber
(Tectum or equivalent)*
• Gypsum*

Roof Surveys Required

• Structural Concrete
• Lightweight Insulating
Concrete**
• Existing Spray Polyurethane
Foam
• Any existing system with a vapor
retarder
• Any existing system that is a
recover system
• Any existing system with
significant ponding water (e.g.
poor drainage)

Liquid-Applied Limited Warranty
Project Size
Roof Survey Criteria

Any Project Size
Roof Surveys Recommended*

*Without significant ponding water. Minimum of (3) three roof cuts for the first 100 squares (929 sq m) and (1) one
test cut per additional 100 squares (929 sq m) are required to verify existing roof conditions are acceptable and/or to
determine where moisture is present.
**For lightweight insulating concrete decks, please contact GAF Technical Services at 800-766-3411.
†Roof moisture surveys are not required/recommended for any system installed over an existing standing seam metal
roof or when the liquid-applied roofing system is applied directly to an approved deck (not as a recover system).

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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REPAIR

Damaged Substrate Treatment: Metal
Areas of Concern

Treatment

Rust Areas

• Severely damaged or rusted seams and/or fasteners must be replaced.
Roof panels that are corroded to the point where they have holes must be
replaced.
• Light rust areas must be treated to prevent further deterioration on metal
panels. Roof surface shall have no more than 20% rust or must have
panels replaced.

Fasteners

• All fasteners must be retightened, secured, or replaced as necessary. All
stripped fasteners must be replaced with new larger fasteners.
• All deteriorated and missing fasteners must be replaced. All fasteners
must be fully encapsulated with HydroStop® PremiumCoat® Butter Grade
Flashing or fastened with UniCap Fastener Covers (refer to the Product
Data Sheet for specific application requirements).

Dented / Damaged Panels

• Dents must be mechanically removed to the maximum extent possible.
• Cover broken rib area with a sheet metal cap and seal with HydroStop®
PremiumCoat® Butter Grade Flashing prior to attaching the cap with
fasteners.
• Severely damaged roof panels must be replaced.

Excessive Gaps

• Seal cracks, joints, penetrations, and curbs with appropriate sealant
materials as recommended.

Seams

• Repair all seams as needed. Refer to the Seam Treatment section in this
Manual for specific seam treatment guidance.

Open Ridge Vents

• Replace or install sheet metal caps over the open ridge vents when they
are rusted on the inside and/or located in a harsh environment (e.g., salt
water areas).
• Do not seal weep holes on vents.

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Substrate
Conditions

Inspect and make all necessary repairs to damaged substrates. Refer to the Damaged Substrate
Treatment sections below for substrate-specific information.

Damaged Substrate Treatment: Non-Metal
Substrate
Conditions

Substrate

Treatment

TPO

• Any areas where TPO has torn, cracked, and/or buckled, or where
scrim is exposed must be repaired using similar compatible materials
to the current roof.
• Any wet insulation must be replaced.
• Allow at least 48 hours drying time after the cleaning process before
application of HydroStop® PremiumCoat® liquid-applied products.

PVC or Hypalon

• Any areas where PVC or Hypalon has torn, cracked, and/or buckled,
or where scrim is exposed must be repaired using similar compatible
materials to the current roof.
• Any wet insulation must be replaced.
• Allow at least 48 hours drying time after the cleaning process before
application of HydroStop® PremiumCoat® liquid-applied products.

Spray Polyurethane Foam

• All areas where the urethane foam has degraded must be scarified
and re-foamed to bring substrate to a smooth, workable surface.
• Any areas where foam has become wet must be removed and refoamed.

EPDM

• Any areas where EPDM has torn, cracked, and/or buckled must be
repaired using similar compatible materials to the current roof.
• Any wet insulation must be replaced.
• Allow at least 48 hours drying time after the cleaning process before
application of HydroStop® PremiumCoat® liquid-applied products.

Mineral & Granule Surfaced BUR or
Modified Bitumen (SBS & APP)
OR
Smooth Surfaced BUR or Modified
Bitumen (SBS & APP)

• Any areas where asphaltic membrane has blistered, buckled, become
wet and/or otherwise been damaged must be removed and repaired
using similar compatible materials to the current roof.
• New BUR or modified bitumen repair materials must be allowed to
weather at least 30 days before applying liquid-applied products to
repaired areas.
• All areas where BUR or modified bitumen surface have significantly
cracked (gaps 1/16” [1.6 mm] or greater in width and/or depth) must
be repaired using flashing grade coating to create a smooth, workable
surface on the substrate.
• Allow flashing grade coating at least 24 hours drying time before
application of HydroStop® PremiumCoat® liquid-applied products.
Areas with thicker applications may require additional drying time.
• Gravel-surfaced BUR or modified bitumen roofing systems are not
a suitable substrate to receive a HydroStop® PremiumCoat® liquidapplied coating.

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Damaged Substrate Treatment: Non-Metal (Cont’d.)
Substrate

Treatment

Structural Concrete

• All large or excessive gaps (greater than 1/4” [6 mm]) must be repaired
using high-quality concrete grout. Grout must fully cure before application
of HydroStop® PremiumCoat® liquid-applied coating system.
• Correct areas of ponding water.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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Substrate
Conditions

Corrugated Structural
Transite Panels

• All large or excessive gaps (greater than 1/4” [6 mm]) existing between
roof panels must be filled or made flush with closed-cell foam strips or
polyurethane foam to pre-fill voids.
• All fasteners must be retightened, secured, or replaced as necessary. All
stripped fasteners must be replaced with larger fasteners.
• All deteriorated or missing fasteners must be replaced. All fasteners must
be fully encapsulated with HydroStop® PremiumCoat® Butter Grade
Flashing or fastened with UniCap Fastener Covers.
• Repair all horizontal seams as needed. Refer to the Seam Treatment
section in this Manual for specific seam treatment guidance.
• Many of these panels can contain asbestos. Refer to the Environmental
Considerations in the Cleaning Procedures section in this Manual for
further information.

CLEANING PROCEDURES
Substrate
Conditions

Treatment

General Surface Prep

• Clean and prepare surfaces to receive liquid-applied roofing products.
Remove all dirt, dust, loose and flaking particles, grease, oil, laitance,
pollution fallout, and other contaminants that may interfere with proper
adhesion.
• Use a stiff bristle push broom and/or pressure washing for cleaning and
surface preparation.
• When encountering roof substrates that have living organisms such as
algae, mold or fungus , a sterilant such as 3:1 bleach solution must be used
to kill and remove these organisms during the roof cleaning.

Pressure Washing

• Substrate must be pressure-washed with water and/or approved cleaner.
Refer to the Cleaner & Primer Guide in this Manual for specific cleaner
information for the substrate you are working with.
• A minimum working pressure of 2,000 psi is to be used to remove all dirt,
dust, chalking and waste products (oil, oil-based roof cements, solvents,
grease, animal fats, etc.).
• Concrete, EPDM, and metal substrates should use a minimum working
pressure of 3,000 psi.
• Care should be taken not to damage the roof surface or inject water into
the substrate during washing.
• Allow at least 48 hours for complete drying after the cleaning process.

Important! Environmental
Considerations

• Corrugated or structural transite panels are likely to contain significant
amounts of asbestos, which may be released during pressure-washing.
Asbestos dust is an extreme health hazard and known as a carcinogen. It is
the Installer’s responsibility to check with state and local agencies regarding
proper disposal, as well as the proper protection for workers exposed to
this material.
• Roof wash-off catchment systems should be in place when required. Be
sure to follow state and local requirements for roof-wash off catchments
during the cleaning process.

Note: Under no circumstances does GAF have any liability for expenses arising out of or associated with the
presence of asbestos-containing materials or any other allegedly hazardous substances or materials on the roof to
which the new GAF roofing materials are being applied.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
16

GENERAL SUBSTRATE PREPARATION

Areas of Concern

Preparation

Crickets

• Sheet metal crickets must be installed according to metal deck
manufacturer's specifications.
• New crickets must be sealed with HydroStop® PremiumCoat® Butter
Grade Flashing under the flanges before they are mechanically attached
to the curb unit and metal roof panel.
• Stitch-screw cricket flanges to the curb unit and metal roof panel while
the HydroStop® PremiumCoat® Butter Grade Flashing is still wet using
fasteners.

Ponding Water Areas

• Make every effort to eliminate all ponding water areas prior to coatings
application.
• Treat ponding water areas which cannot be eliminated with HydroStop®
BarrierGuard® bulked with HydroFiber prior to application of other
coatings. If ponding water cannot be eliminated, areas should be treated
with a 3-course application of HydroStop® BarrierGuard® and fabric.

Residual Asphalt

• Remove any existing asphaltic roof coating.
• Any residual asphalt must be coated with UniBase Primer (see Cleaner &
Primer Guide).

Pre-Finished Metal Panels

• If roof panel surfaces are known or suspected to contain Kynar-500,
other fluoropolymers, or silicone, test patches need to be prepared with
and without the use of XR-2000 Primer (see Cleaner & Primer Guide).
Based on test patch adhesion results, Installer should apply primer on
pre-finished metal panels per specifications.

Pitch Pans

• Pitch pans must be capped with sheet metal so they can be sealed
with HydroStop® PremiumCoat® Butter Grade Flashing. Contact GAF's
Technical Services Department for more information.

Neoprene Pipe Boots

• Install neoprene boots prior to performing flashing work for certain types
of pipe penetrations. Neoprene boots first must be sealed to the roof
using a bead of HydroStop® PremiumCoat® Butter Grade Flashing prior
to mechanical attachment with fasteners.

Condensate Lines

• Condensate lines should be installed from the HVAC units to gutters as
part of the overall roofing contract. Type of piping used for condensate
lines may vary depending on local building codes.
• Condensate lines must be securely fastened to panel ribs. All fastener
heads must be encapsulated with HydroStop® PremiumCoat® Butter
Grade Flashing.

Cinch Straps at Panel End Laps

• Re-tighten cinch straps as necessary.
• Surround each strap and fastener head with a bead of HydroStop®
PremiumCoat® Butter Grade Flashing.
• Encapsulate the cinch strap water channel, then seal the entire lap,
strap, and fastener heads with a minimum of 12 inches (305 mm)
width of HydroStop® PremiumCoat® Butter Grade Flashing. Feather
the HydroStop® PremiumCoat® Butter Grade Flashing out. Fabric is not
required.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
17

Substrate
Conditions

Substrate Preparation: Metal

Substrate Preparation: Metal (Cont’d.)
Substrate
Conditions

Areas of Concern

Preparation

Ridge Caps

• All ridge caps must be flashed with HydroStop® PremiumCoat® Butter Grade
Flashing with fabric.
• All voids and open areas in the ridge cap must be filled with polyurethane
foam prior to application of the coating and fabric.
• For metal "Z" closures which are located within 2 inches (51 mm) of the
ridge cap edge, remove all exposed sealant and apply a liberal bead of
HydroStop® PremiumCoat® Butter Grade Flashing with fabric to all sides of
the "Z" closure where they intersect with both the roof panel and ridge cap.

Rakes

• All fixed rake details for the roof must be secured and sealed with 12 inches
(305 mm) minimum width of HydroStop® PremiumCoat® Butter Grade
Flashing with fabric.
• If fixed rake metal is fastened to the top of roof panel ribs and extends back
onto the roof, trim off any excess metal and follow horizontal seam flashing
procedures.
• All voids and open areas must be filled with polyurethane foam prior to
application of the coating and fabric.

Parapet Walls

• All parapet wall details within the roof system must be secured and sealed
with 12 inches (305 mm) minimum width of HydroStop® PremiumCoat®
Butter Grade Flashing with fabric.
• If parapet wall flashing metal is fastened to the top of roof panel ribs and
extends back onto the roof, trim off any excess metal and follow horizontal
seam flashing procedures.
• All voids and open areas must be filled with polyurethane foam prior to
application of HydroStop® PremiumCoat® Butter Grade Flashing with fabric.
• Fabric must be cut around all fasteners so it lies flat. United Coatings™
UniCap fastener covers can alternatively be used.

Standing Seam Panels

• Contact GAF’s Technical Services Department (800-766-3411).

Curb Flashings

• All curb flashings, including cricket details, must be flashed with at least a 12
inch (305 mm) width of HydroStop® PremiumCoat® Butter Grade Flashing
with fabric.
• Encapsulate all fasteners using HydroStop® PremiumCoat® Butter Grade
Flashing with fabric. Do not bridge fasteners.
• The fabric must be cut around all fasteners so the fabric lies flat.

Penetrations

• HydroStop® PremiumCoat® Butter Grade Flashing with fabric should be
applied around the base of all penetrations, extending at least 6 inches (152
mm) up the vertical and 6 inches (152 mm) onto the base.
• Cut the fabric to accommodate the shape of the penetration.

Skylights

• Curb skylights must be treated in the same fashion as curb flashings.
• After flashing work has been completed and the coating has cured, treat
deteriorated fiberglass skylight panels with United Coatings™ Acrysheen
Sealer.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
18

Substrate Preparation: Metal (Cont’d.)

HORIZONTAL SEAMS

Preparation

Ribbed Seam

• All ribbed panel vertical seams must be sealed with HydroStop®
PremiumCoat® Butter Grade Flashing. Feather the coating until
seams are no longer visible while brushing in the direction parallel
to the seam.

Standing Seam

• All standing vertical seams must be sealed with a 1/2 inch (12 mm)
bead of HydroStop® PremiumCoat® Butter Grade Flashing. Feather
the coating until seams are no longer visible while brushing in the
direction parallel to the seam.

Standing “T” Seam

• Both vertical seams of the standing "T" must be flashed with a 1/2
inch (12 mm) bead of the HydroStop® PremiumCoat® Butter Grade
Flashing and brushed into the seams.

Inverted “J” Seam

• In snowy climates and/or when roof leaks are suspected, recrimping the short leg of the seam all the way under the horizontal
portion of the inverted "J" seam is required. Brush or trowel-apply
HydroStop® PremiumCoat® Butter Grade Flashing over the newly
created single lock vertical seam. Portable seamers may be used to
perform the re-crimping.

Corrugated Seam

• All corrugated panel vertical seams must be sealed with
HydroStop® PremiumCoat® Butter Grade Flashing. Feather the
coating until seams are no longer visible while brushing in the
direction parallel to the seam.

Batten Seam

• Both vertical seams of the batten must be flashed with a 1/2
inch (12 mm) bead of HydroStop® PremiumCoat® Butter Grade
Flashing. Feather the coating until seams are no longer visible
while brushing in the direction parallel to the seam.

Horizontal Seam

• All seams must be reinforced with two layers of HydroStop®
PremiumCoat® Butter Grade Flashing with fabric or TOPCOAT®
Liquid Fabric.
• The coating must be feathered at least 1 inch (25 mm) beyond
each side of the 6 inch (152 mm) width to allow water to flow over
the seam.
• Fabric must be cut around all fasteners so it lies flat.
• For ribbed roof panels, the fabric must be applied over panel ribs
in continuous lengths. A minimum 2 inches (51 mm) overlap is
required for all splices in fabric.
• Horizontal seams must be secured with fasteners on the high side
of every other corrugation, spaced no more than 12 inches (305
mm) on center.
• The horizontal seam must be made flush by installing two
fasteners per flute.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
19

Substrate
Conditions

VERTICAL SEAMS

Areas of Concern

Substrate Preparation: TPO
Substrate
Conditions

Areas of Concern

Treatment

Parapet Walls

• Repair all open seams and any loose or failed terminations with inkind materials prior to application of HydroStop® PremiumCoat®
Butter Grade Flashing with fabric.
• All parapet wall details within the roof system must be secured
and sealed with a 12 inch (305 mm) minimum width of
HydroStop® PremiumCoat® Butter Grade Flashing with fabric.
• Fabric must be cut around all fasteners so it lies flat.

Curb Flashings

• All curb flashings, including cricket details, must be flashed with
at least a 12 inch (305 mm) width of HydroStop® PremiumCoat®
Butter Grade Flashing with fabric.
• Encapsulate all fasteners using HydroStop® PremiumCoat® Butter
Grade Flashing with fabric. Do not bridge fasteners.
• Fabric must be cut around all fasteners so it lies flat.

Penetrations

• HydroStop® PremiumCoat® Butter Grade Flashing with fabric must
be applied around the base of all penetrations, extending at least
6 inches (152 mm) up the vertical and 6 inches (152 mm) onto the
base.
• Cut the fabric to accommodate the shape of the penetration.

Skylights

• Curb skylights must be treated in the same fashion as curb
flashings.
• After flashing work has been completed and the coating has cured,
treat deteriorated fiberglass skylight panels with United Coatings™
Acrysheen Sealer.

Pitch Pans

• Pitch pans must be capped with sheet metal so that they may be
sealed with HydroStop® PremiumCoat® Butter Grade Flashing.

Condensate Lines

• Condensate lines must be installed from HVAC units to gutters as
part of the overall drainage system. The type of piping used for
condensate lines may vary depending on local building codes.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
20

Substrate Preparation: PVC & Hypalon®
Areas of Concern

Treatment

Curb Flashings

• All curb flashings, including cricket details, must be flashed with
at least a 12 inch (305 mm) width of HydroStop® PremiumCoat®
Butter Grade Flashing with fabric.
• Encapsulate all fasteners using HydroStop® PremiumCoat® Butter
Grade Flashing with fabric. Do not bridge fasteners.
• Fabric must be cut around all fasteners so it lies flat.

Penetrations

Skylights

• Curb skylights must be treated in the same fashion as curb
flashings.
• After flashing work has been completed and the coating has cured,
treat deteriorated fiberglass skylight panels with United Coatings™
Acrysheen Sealer.

Pitch Pans

• Pitch pans must be capped with sheet metal so that they may be
sealed with HydroStop® PremiumCoat® Butter Grade Flashing.

Condensate Lines

• Condensate lines must be installed from HVAC units to gutters as
part of the overall drainage system. The type of piping used for
condensate lines may vary depending on local building codes.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
21

Substrate
Conditions

Parapet Walls

Substrate Preparation: EPDM
Substrate
Conditions

Areas of Concern

Treatment

Parapet Walls

Curb Flashings

• All curb flashings, including cricket details, must be flashed with
at least a 12 inch (305 mm) width of HydroStop® PremiumCoat®
Butter Grade Flashing with fabric.
• Encapsulate all fasteners using HydroStop® PremiumCoat® Butter
Grade Flashing with fabric. Do not bridge fasteners.
• Fabric must be cut around all fasteners so it lies flat.

Penetrations

Skylights

• Curb skylights must be treated in the same fashion as curb
flashings.
• After flashing work has been completed and the coating has cured,
treat deteriorated fiberglass skylight panels with United Coatings™
Acrysheen Sealer.

Pitch Pans

• Pitch pans must be capped with sheet metal so that they may be
sealed with HydroStop® PremiumCoat® Butter Grade Flashing.

Condensate Lines

• Condensate lines must be installed from HVAC units to gutters as
part of the overall drainage system. The type of piping used for
condensate lines may vary depending on local building codes.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
22

Substrate Preparation: Smooth & Granulated Surfaced Asphaltic
Areas of Concern

Treatment

Curb Flashings

• All curb flashings, including cricket details, must be flashed with
at least a 12 inch (305 mm) width of HydroStop® PremiumCoat®
Butter Grade Flashing with fabric.
• Encapsulate all fasteners using HydroStop® PremiumCoat® Butter
Grade Flashing with fabric. Do not bridge fasteners.
• Fabric must be cut around all fasteners so it lies flat.

Penetrations

Skylights

• Curb skylights must be treated in the same fashion as curb
flashings.
• After flashing work has been completed and the coating has cured,
treat deteriorated fiberglass skylight panels with United Coatings™
Acrysheen Sealer.

Pitch Pans

• Pitch pans must be capped with sheet metal so that they may be
sealed with HydroStop® PremiumCoat® Butter Grade Flashing.

Condensate Lines

• Condensate lines must be installed from HVAC units to gutters as
part of the overall drainage system. The type of piping used for
condensate lines may vary depending on local building codes.

NOTE: For spudded gravel surfaces, please contact GAF Technical Services (800-766-3411).

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
23

Substrate
Conditions

Parapet Walls

Substrate Preparation: Structural Concrete
Substrate
Conditions

Areas of Concern

Treatment

Parapet Walls

• Repair all cracked, spalled and open concrete holes with an in-kind
cementitious patch. Repair any loose or failed seams with similar
materials as originally used. This is commonly a polyurethane
sealant with a closed cell polyethylene backer rod.
• All parapet wall details within the roof system must be secured
and sealed with a 12 inch (305 mm) minimum width of
HydroStop® PremiumCoat® Butter Grade Flashing with fabric.
• Fabric must be cut around all fasteners so it lies flat.

Curb Flashings

• All curb flashings, including cricket details, must be flashed with
at least a 12 inch (305 mm) width of HydroStop® PremiumCoat®
Butter Grade Flashing with fabric.
• Encapsulate all fasteners using HydroStop® PremiumCoat® Butter
Grade Flashing with fabric. Do not bridge fasteners.
• Fabric must be cut around all fasteners so it lies flat.

Penetrations

Skylights

• Curb skylights must be treated in the same fashion as curb
flashings.
• After flashing work has been completed and the coating has cured,
treat deteriorated fiberglass skylight panels with United Coatings™
Acrysheen Sealer.

Pitch Pans

• Pitch pans must be capped with sheet metal so that they may be
sealed with HydroStop® PremiumCoat® Butter Grade Flashing.

Condensate Lines

• Condensate lines must be installed from HVAC units to gutters as
part of the overall drainage system. The type of piping used for
condensate lines may vary depending on local building codes.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
24

Adhesion Testing

When adhesion tests are conducted:
• Test patches shall be labeled and photographed to document adhesion results.
• Installer can consult with GAF’s Technical Services Department (800-766-3411) concerning all
adhesion test results.
GAF recommends either of the following test methods:

Test Method #1: Test Patches
Overview

Patch testing gives information about the bond strength created
between a liquid-applied product and a substrate.

Preparation

• Installer should prepare no fewer than three (3) test patches at
different locations on the roof for all questionable roof substrates
to verify adhesion of the liquid-applied coating system.

Test Method

• Minimum test patch size should be 1 square foot (0.09 square
meter).
• Allow at least seven (7) full 24 hour days of drying time after
application of the test patches before checking adhesion.
• Check adhesion by slicing an “X” (approx. 6” [152 mm] in size) near
the center of the test patch.
• Using a spatula, try to remove the material at the center of the
“X”.

Acceptable Result:

• Test patches that show good adhesion will release or chip away
from the surface in very small pieces.

Unacceptable Result:

• Test patches that peel off of the surface and show the underlying
substrate reflect poor adhesion.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
25

Substrate
Conditions

Adhesion testing is generally performed to verify the suitability of any substrate to receive a liquidapplied coating system. It is the responsibility of the roofing contractor to determine the suitability of
the substrate prior to the application of a liquid-applied coating system.

Substrate
Conditions

Test Method #2: Field Peel Adhesion (Alternate to Test Patches)
Overview

ASTM D903 “Peel Adhesion” is found in all roof coating standards
and is especially well-suited to field testing with elastomeric
materials. Primers and enamels may also be evaluated by a similar
test called ASTM D3359 “Tape Adhesion.” It may also be important to
run the test wet; this is called “wet adhesion.”

Preparation101

• Make a mock-up of the intended coating system on the existing
roof surface.
• Duplicate any mechanical surface preparation.
• Simulate cleaners and power washing.
• A worn Scotch-Brite® cleaning pad makes a good power washing
simulation.
• Prime as specified.
• Apply a layer of elastomeric coating to the substrate.
• Installer should prepare no fewer than three (3) test patches at
different locations on the roof for all questionable roof substrates
to verify adhesion of the liquid-applied coating system.

Test Method

Optional

• Wet about 6” (152 mm) of a precut 1” (25 mm) wide by 12” (305
mm) long fabric strip with the coating.
• Allow the remaining 6” (152 mm) of the fabric to be available to
pull on the test sample.
• Apply another layer of coating to encapsulate the wetted section of
fabric.
• Allow to dry. This can be anywhere from 24 hours to 2 weeks.
• In warm weather, 1 day may be sufficient.
• In cold weather, 5 days is often required.
• The standard practice is 1 week.
• Soak prior to testing (best practice).
• One hour is usually sufficient; use wet rag and cover with a
bucket lid or plastic.
• Some coatings like polyvinylidene difluoride (PVDF) or silicone
may take longer.
• Pre-cut 1” (25 mm) wide strips of butyl tape work faster and can be
used in a post installation inspection. A “wet adhesion” version can
be accomplished by soaking the roof area first as indicated above,
but follow with a towel dry, and then use butyl tape to run the pull
test. The butyl tape can be easier to use with a gauge as it will bond
to itself making a perfect loop.

Quantitative Evaluation (best practice)
• Use a force gauge such as a digital fish scale or trigger
pressure gauge.
• A loop, staple or clamp may be used to hold the fabric in
the gauge.
• Pull slowly; the peak value should be above 2 pounds/
inch (2 PLI).

Qualitative Evaluation
Excellent: Coating tears up the substrate (cohesive
failure of substrate)
Very Good: Most of the coating remains on the
substrate (cohesive failure of coating)
Good: Some coating remains on the substrate
(partial cohesive failure of coating)
Fair: Coating pulls clean but pulls below 2 pounds/
inch (2 PLI)
Poor: Test strip comes off easily and cleanly
(complete cohesive failure of coating)

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
26

Quick Specss

Section 3
Quick Specs

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
27

Quick Specs

HydroStop® PremiumCoat® Quick Spec Directory
Spec Number

Substrate Specification

Page #

HS-1

Metal – HydroStop® PremiumCoat®

HS-2

Smooth & Granulated Asphaltic – Hydro�top™ PremiumCoat®

HS-3

TPO – HydroStop® PremiumCoat®

HS-4

PVC – HydroStop® PremiumCoat®

HS-5

Hypalon® - HydroStop® PremiumCoat®

HS-6

EPDM – HydroStop® PremiumCoat®

HS-7

Structural Concrete – HydroStop® PremiumCoat®

HS-8

Corrugated Structural Transite Panel – HydroStop® PremiumCoat®

HS-9

ISO – HydroStop® PremiumCoat®

HS-10

Gypsum (DensDeck & SecuRock) – HydroStop® PremiumCoat®

HS-11

Warranty Extension/Renewal – HydroStop® PremiumCoat®

Quick Specs are abbreviated specifications and are not meant to replace detailed
specifications. Complete 3-part CSI System Specifications are available at
www.gaf.com.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
28

QUICK SPEC

Method

• Use GAF Roof Brush to apply HydroStop® PremiumCoat® Foundation Coat
• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

Application
Instructions

• Roof must be clean, dry, and tight.
• Adhesion test required to ensure proper adhesion to substrate(s).
• Apply at 50°F (10°C) and rising with no rain, dew, fog or freezing temperatures in
forecast for 24 hours.
• GAF recommends that the surface temperature be at or less than 110°F (43°C)
during application.
1. Tighten and/or replace existing fasteners.
2. Power-wash roof to ensure it is free of dirt, debris, oil, and other contaminants
that could negatively affect adhesion. United Cleaning Concentrate (UCC) is
recommended to clean the roof. Allow roof to completely dry.
3. Install crickets to divert water and complete other necessary sheet metal repairs.
4. Prime rusty areas with Acrylex 400 Primer or StableRust Rust-Inhibiting Primer.
For severe rust, prime area with Lock-Down Primer.
5. Treat seams.
6. Treat all roof penetrations, skylight curbs & rake edges with HydroStop®
PremiumCoat® Butter Grade Flashing with fabric.
7. Encapsulate fasteners with HydroStop® HydroCap Fastener Caps or HydroStop®
PremiumCoat® Butter Grade Flashing.
8. Before applying the HydroStop® PremiumCoat® System, an adhesion test is
required to ensure an adhesion of a minimum of 2.0 PLI. Test patches to be
applied with system rates listed below.
9. Apply HydroStop® PremiumCoat® Foundation Coat and Finish Coat per the chart
below.
METAL
HYDROSTOP® PREMIUMCOAT® SYSTEM

Foundation Coat

10 Year

15 Year

20 Year

Finish Coat

Area

Total
(Gal/Sq)

DFT*
(mils)

1st Coat 2nd Coat 3rd Coat
(Gal/Sq) (Gal/Sq) (Gal/Sq)

Horizontal & Vertical
Seams w/fabric

2.5

0.75

Field of Roof
(no fabric)

N/A

Horizontal & Vertical
Seams w/fabric

2.5

Field of Roof
(no fabric)

System

Warranty

Total
(Gal/Sq)

DFT*
(mils)

Total
(Gal/Sq)

DFT*
(mils)

0.75

1.5

4.0

0.75

1.5

1.0

2.0

4.5

N/A

1.0

2.0

Horizontal & Vertical
Seams w/fabric

2.5

1.0

3.0

5.5

Field of Roof
(no fabric)

N/A

1.0

3.0

Emerald Diamond
Pledge™ Pledge™

Yes

*DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile, application technique &
waste factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
29

Quick Specs

METAL – HYDROSTOP® PREMIUMCOAT® (HS-1)

Quick Specs

QUICK SPEC

SMOOTH & GRANULATED ASPHALTIC – HYDROSTOP® PREMIUMCOAT® (HS-2)
NOTE: The following “Quick Spec” is an abbreviated specification and is not meant to replace the detailed
specification. Read the entire 3-Part CSI System Specification prior to starting the project. Specifications are
available at www.gaf.com.

Method

• Use GAF Roof Brush to apply HydroStop® PremiumCoat® Foundation Coat
• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

• Moisture survey recommended for all non-metal roofs.
• Roof must be clean, dry, and tight.
• Adhesion test required to ensure proper adhesion to substrate(s).
• Apply at 50°F (10°C) and rising with no rain, dew, fog or freezing temperatures in
forecast for 24 hours.
• GAF recommends that the surface temperature be at or less than 110°F (43°C)
during application.

Application
Instructions

1. Conduct moisture survey and remove/replace all wet areas.
2. Repair membrane including seams, penetrations, flashings, curbs, and
terminations with like materials.
3. Power-wash roof to ensure it is free of dirt, debris, oil, and other contaminants
that could negatively affect adhesion. United Cleaning Concentrate (UCC) is
recommended to clean the roof. Allow roof to completely dry.
4. Prime with UniBase Primer.
5. Treat all roof penetrations, drains, curbs, and scuppers.
6. Before applying the HydroStop® PremiumCoat® System, an adhesion test is
required to ensure an adhesion of a minimum of 2.0 PLI. Test patches to be
applied with system rates listed below.
7. Apply HydroStop® PremiumCoat® Foundation Coat and Finish Coat per the chart
below.
SMOOTH AND GRANULATED ASPHALTIC
HYDROSTOP® PREMIUMCOAT® SYSTEM

Foundation Coat
(with fabric)

Finish Coat

Total
(Gal/Sq)

DFT*
(mils)

1st Coat
(Gal/Sq)

2nd Coat
(Gal/Sq)

10
Year

2.5

0.75

15
Year

2.5

20
Year

2.5

3rd Coat
(Gal/Sq)

System

Warranty

Total
(Gal/Sq)

DFT*
(mils)

Total
(Gal/Sq)

DFT*
(mils)

0.75

1.5

4.0

1.0

2.0

4.5

1.0

3.0

5.5

1.0

Emerald
Pledge™

Diamond
Pledge™

Yes

*DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile, application technique &
waste factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
30

QUICK SPEC

NOTE: The following “Quick Spec” is an abbreviated specification and is not meant to replace the detailed
specification. Read the entire 3-Part CSI System Specification prior to starting the project. Specifications are
available at www.gaf.com.
• Use GAF Roof Brush to apply HydroStop® PremiumCoat® Foundation Coat
Method
• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

Application
Instructions

1. Conduct moisture survey and remove/replace all wet areas.
2. Repair membrane including seams, penetrations, flashings, curbs, and
terminations with like materials.
3. Power-wash roof to ensure it is free of dirt, debris, oil, and other contaminants
that could negatively affect adhesion. United Cleaning Concentrate (UCC) is
recommended to clean the roof. Allow roof to completely dry.
4. Prime with TPO Red Primer.
5. Treat all roof penetrations, drains, curbs, and scuppers.
6. Before applying the HydroStop® PremiumCoat® System, an adhesion test is
required to ensure an adhesion of a minimum of 2.0 PLI. Test patches to be
applied with system rates listed below.
7. Apply HydroStop® PremiumCoat® Foundation Coat and Finish Coat per the chart
below.
TPO
HYDROSTOP® PREMIUMCOAT® SYSTEM

Foundation Coat
(with fabric)

Finish Coat

Total
(Gal/Sq)

DFT*
(mils)

1st Coat
(Gal/Sq)

2nd Coat
(Gal/Sq)

10
Year

2.5

0.75

15
Year

2.5

20
Year

2.5

3rd Coat
(Gal/Sq)

System

Warranty

Total
(Gal/Sq)

DFT*
(mils)

Total
(Gal/Sq)

DFT*
(mils)

0.75

1.5

4.0

1.0

2.0

4.5

1.0

3.0

5.5

1.0

Emerald
Pledge™

Diamond
Pledge™

Yes

*DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile, application technique &
waste factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
31

Quick Specs

TPO – HYDROSTOP® PREMIUMCOAT® (HS-3)

Quick Specs

QUICK SPEC

PVC – HYDROSTOP® PREMIUMCOAT® (HS-4)
NOTE: The following “Quick Spec” is an abbreviated specification and is not meant to replace the detailed
specification. Read the entire 3-Part CSI System Specification prior to starting the project. Specifications are
available at www.gaf.com.

Method

• Use GAF Roof Brush to apply HydroStop® PremiumCoat® Foundation Coat
• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

Application
Instructions

1. Conduct moisture survey and remove/replace all wet areas.
2. Repair membrane including seams, penetrations, flashings, curbs, and
terminations with like materials.
3. Power-wash roof to ensure it is free of dirt, debris, oil, and other contaminants
that could negatively affect adhesion. United Cleaning Concentrate (UCC) is
recommended to clean the roof. Allow roof to completely dry.
4. In most cases, no primer is required for this substrate.
5. Treat all roof penetrations, drains, curbs, and scuppers.
6. Before applying the HydroStop® PremiumCoat® System, an adhesion test is
required to ensure an adhesion of a minimum of 2.0 PLI. Test patches to be
applied with system rates listed below.
7. Apply HydroStop® PremiumCoat® Foundation Coat and Finish Coat per the
chart below.
PVC
HYDROSTOP® PREMIUMCOAT® SYSTEM

Foundation Coat
(with fabric)

Finish Coat

Total
(Gal/Sq)

DFT*
(mils)

1st Coat
(Gal/Sq)

2nd Coat
(Gal/Sq)

10
Year

2.5

0.75

15
Year

2.5

20
Year

2.5

3rd Coat
(Gal/Sq)

System

Warranty

Total
(Gal/Sq)

DFT*
(mils)

Total
(Gal/Sq)

DFT*
(mils)

0.75

1.5

4.0

1.0

2.0

4.5

1.0

3.0

5.5

1.0

Emerald
Pledge™

Diamond
Pledge™

Yes

*DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile, application technique &
waste factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
32

QUICK SPEC

Method

• Use GAF Roof Brush to apply HydroStop® PremiumCoat® Foundation Coat
• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

Application
Instructions

1. Conduct moisture survey and remove/replace all wet areas.
2. Repair membrane including seams, penetrations, flashings, curbs, and
terminations with like materials.
3. Power-wash roof to ensure it is free of dirt, debris, oil, and other contaminants
that could negatively affect adhesion. United Cleaning Concentrate (UCC) is
recommended to clean the roof. Allow roof to completely dry.
4. In most cases, no primer is required for this substrate.
5. Treat all roof penetrations, drains, curbs, and scuppers.
6. Before applying the HydroStop® PremiumCoat® System, an adhesion test is
required to ensure an adhesion of a minimum of 2.0 PLI. Test patches to be
applied with system rates listed below.
7. Apply HydroStop® PremiumCoat® Foundation Coat and Finish Coat per the chart
below.
HYPALON®
HYDROSTOP® PREMIUMCOAT® SYSTEM

Foundation Coat
(with fabric)

Finish Coat

Total
(Gal/Sq)

DFT*
(mils)

1st Coat
(Gal/Sq)

2nd Coat
(Gal/Sq)

10
Year

2.5

0.75

15
Year

2.5

20
Year

2.5

3rd Coat
(Gal/Sq)

System

Warranty

Total
(Gal/Sq)

DFT*
(mils)

Total
(Gal/Sq)

DFT*
(mils)

0.75

1.5

4.0

1.0

2.0

4.5

1.0

3.0

5.5

1.0

Emerald
Pledge™

Diamond
Pledge™

Yes

*DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile, application technique &
waste factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
33

Quick Specs

HYPALON® - HYDROSTOP® PREMIUMCOAT® (HS-5)

Quick Specs

QUICK SPEC

EPDM – HYDROSTOP® PREMIUMCOAT® (HS-6)
NOTE: The following “Quick Spec” is an abbreviated specification and is not meant to replace the detailed
specification. Read the entire 3-Part CSI System Specification prior to starting the project. Specifications are
available at www.gaf.com.

Method

• Use GAF Roof Brush to apply HydroStop® PremiumCoat® Foundation Coat
• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

Application
Instructions

1. Conduct moisture survey and remove/replace all wet areas.
2. Repair membrane including seams, penetrations, flashings, curbs, and
terminations with like materials.
3. Clean and allow roof to completely dry.
4. Prime using either Adhere-It II or CleanAct Rinsable Primer.
5. Treat all roof penetrations, drains, curbs, and scuppers.
6. Before applying the HydroStop® PremiumCoat® System, an adhesion test is
required to ensure an adhesion of a minimum of 2.0 PLI. Test patches to be
applied with system rates listed below.
7. Apply HydroStop® PremiumCoat® Foundation Coat and HydroStop®
PremiumCoat® Finish Coat per the chart below.
EPDM
HYDROSTOP® PREMIUMCOAT® SYSTEM

Foundation Coat
(with fabric)

Finish Coat

Total
(Gal/Sq)

DFT*
(mils)

1st Coat
(Gal/Sq)

2nd Coat
(Gal/Sq)

10
Year

2.5

0.75

15
Year

2.5

20
Year

2.5

3rd Coat
(Gal/Sq)

System

Warranty

Total
(Gal/Sq)

DFT*
(mils)

Total
(Gal/Sq)

DFT*
(mils)

0.75

1.5

4.0

1.0

2.0

4.5

1.0

3.0

5.5

1.0

Emerald
Pledge™

Diamond
Pledge™

Yes

*DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile, application technique &
waste factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
34

QUICK SPEC

Method

• Use GAF Roof Brush to apply HydroStop® PremiumCoat® Foundation Coat
• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

• Moisture survey recommended for all non-metal roofs.
• Roof must be clean, dry, and tight.
• Adhesion test required to ensure proper adhesion to substrate(s).
• Apply at 50°F (10°C) and rising with no rain, dew, fog or freezing temperatures
in forecast for 24 hours.
• GAF recommends that the surface temperature be at or less than 110°F (43°C)
during application.
• Concrete must be fully cured (typically 28 days).

Application
Instructions

1. Conduct moisture survey to ensure concrete contains less than 8% moisture.
2. Repair or replace damaged or deteriorated sections with like materials,
allowing cementitious products to cure properly.
3. Power-wash roof to ensure it is free of dirt, debris, oil, and other contaminants
that could negatively affect adhesion. United Cleaning Concentrate (UCC) is
recommended to clean the roof. Allow roof to completely dry.
4. Prime with Epoxy Primer.
5. Treat structural joints with backer rod and compatible sealant.
6. Treat all roof penetrations, drains, curbs, and scuppers.
7. Before applying the HydroStop® PremiumCoat® System, an adhesion test is
required to ensure an adhesion of a minimum of 2.0 PLI. Test patches to be
applied with system rates listed below.
8. Apply HydroStop® PremiumCoat® Foundation Coat and Finish Coat per the
chart below.
STRUCTURAL CONCRETE
HYDROSTOP® PREMIUMCOAT® SYSTEM

Foundation Coat
(with fabric)

Finish Coat

Total
(Gal/Sq)

DFT*
(mils)

1st Coat
(Gal/Sq)

2nd Coat
(Gal/Sq)

10
Year

2.5

0.75

15
Year

2.5

20
Year

2.5

3rd Coat
(Gal/Sq)

System

Warranty

Total
(Gal/Sq)

DFT*
(mils)

Total
(Gal/Sq)

DFT*
(mils)

0.75

1.5

4.0

1.0

2.0

4.5

1.0

3.0

5.5

1.0

Emerald
Pledge™

Diamond
Pledge™

Yes

*DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile, application technique & waste
factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
35

Quick Specs

STRUCTURAL CONCRETE – HYDROSTOP® PREMIUMCOAT® (HS-7)

Quick Specs

QUICK SPEC

CORRUGATED STRUCTURAL TRANSITE PANELS – HYDROSTOP® PREMIUMCOAT® (HS-8)
NOTE: The following “Quick Spec” is an abbreviated specification and is not meant to replace the detailed
specification. Read the entire 3-Part CSI System Specification prior to starting the project. Specifications are
available at www.gaf.com.

Method

• Use GAF Roof Brush to apply HydroStop® PremiumCoat® Foundation Coat
• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

Application
Instructions

1. Repair or replace damaged or deteriorated sections with like materials, allowing
cementitious products to cure properly.
2. Power-wash roof to ensure it is free of dirt, debris, oil, and other contaminants
that could negatively affect adhesion. United Cleaning Concentrate (UCC) is
recommended to clean the roof. Allow to completely dry.
3. Prime with Epoxy Primer.
4. Treat expansion joints with backer rod and compatible sealant. Concrete control
joints and transite gaps in excess of 1/16” (1.6mm) shall also be caulked.
5. Treat all roof penetrations, drains, curbs, and scuppers.
6. Before applying the HydroStop® PremiumCoat® System, an adhesion test is
required to ensure an adhesion of a minimum of 2.0 PLI. Test patches to be
applied with system rates listed below.
7. Apply HydroStop® PremiumCoat® Foundation Coat and Finish Coat per the chart
below.
CORRUGATED STRUCTURAL TRANSITE PANEL
HYDROSTOP® PREMIUMCOAT® SYSTEM

Foundation Coat
(with fabric)

Finish Coat

Total
(Gal/Sq)

DFT*
(mils)

1st Coat
(Gal/Sq)

2nd Coat
(Gal/Sq)

10
Year

2.5

0.75

15
Year

2.5

20
Year

2.5

3rd Coat
(Gal/Sq)

System

Warranty

Total
(Gal/Sq)

DFT*
(mils)

Total
(Gal/Sq)

DFT*
(mils)

0.75

1.5

4.0

1.0

2.0

4.5

1.0

3.0

5.5

1.0

Emerald
Pledge™

Diamond
Pledge™

Yes

*DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile, application technique &
waste factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
36

QUICK SPEC

Method

• Use GAF Roof Brush to apply HydroStop® PremiumCoat® Foundation Coat
• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

• Roof must be clean, dry, and tight.
• Adhesion test required to ensure proper adhesion to substrate(s).
• Recover over an existing roof: one (1) layer of ISO is required. Refer to local
building code for further insulation requirements.
• New construction or tear-off: one (1) layer of ISO & minimum 1/4” (6.35 mm)
gypsum coverboard OR two (2) layers of fully adhered staggered ISO. If the
top layer is mechanically attached, plates must be encapsulated with Butter
Grade Flashing.
• All seams must be treated with Butter Grade w/fabric OR Foundation Coat w/
fabric.
• Apply at 50°F (10°C) and rising with no rain, dew, fog or freezing temperatures
in forecast for 24 hours.
• GAF recommends that the surface temperature be at or less than 110°F (43°C)
during application.

Application
Instructions

1. Ensure roof is free of dirt, debris, oil, and other contaminants that could
negatively affect adhesion.
2. In most cases, no primer is required for this substrate.
3. Before applying the HydroStop® PremiumCoat® System, an adhesion test is
required to ensure an adhesion of a minimum of 2.0 PLI. Test patches to be
applied with system rates listed below.
4. Apply HydroStop® PremiumCoat® Foundation Coat and Finish Coat per the
chart below.
POLYISOCYANURATE (ISO)
HYDROSTOP® PREMIUMCOAT® SYSTEM

Foundation Coat
(with fabric)

Finish Coat

Total
(Gal/Sq)

DFT*
(mils)

1st Coat
(Gal/Sq)

2nd Coat
(Gal/Sq)

10
Year

2.5

0.75

15
Year

2.5

20
Year

2.5

3rd Coat
(Gal/Sq)

System

Warranty

Total
(Gal/Sq)

DFT*
(mils)

Total
(Gal/Sq)

DFT*
(mils)

0.75

1.5

4.0

1.0

2.0

4.5

1.0

3.0

5.5

1.0

Emerald
Pledge™

Diamond
Pledge™

Yes

* DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile, application technique &
waste factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
37

Quick Specs

POLYISOCYANURATE (ISO) – HYDROSTOP® PREMIUMCOAT® (HS-9)

QUICK SPEC

Quick Specs

GYPSUM (DensDeck & SecuRock) – HYDROSTOP® PREMIUMCOAT® (HS-10)
NOTE: The following “Quick Spec” is an abbreviated specification and is not meant to replace the detailed
specification. Read the entire 3-Part CSI System Specification prior to starting the project. Specifications are
available at www.gaf.com.

Method

• Use GAF Roof Brush to apply HydroStop® PremiumCoat® Foundation Coat
• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

• Roof must be clean, dry, and tight.
• Adhesion test required to ensure proper adhesion to substrate(s).
• If mechanically attached, plates must be encapsulated with Butter Grade Flashing.
• All seams are to be treated with Butter Grade w/fabric OR Foundation Coat w/
fabric.
• Apply at 50°F (10°C) and rising with no rain, dew, fog or freezing temperatures in
forecast for 24 hours.
• GAF recommends that the surface temperature be at or less than 110°F (43°C)
during application.

Application
Instructions

1. Ensure roof is free of dirt, debris, oil, and other contaminants that could
negatively affect adhesion.
2. In most cases, no primer is required for this substrate.
3. Before applying the HydroStop® PremiumCoat® System, an adhesion test is
required to ensure an adhesion of a minimum of 2.0 PLI. Test patches to be
applied with system rates listed below.
4. Apply HydroStop® PremiumCoat® Foundation Coat and Finish Coat per the chart
below.
GYPSUM (DensDeck & SecuRock)
HYDROSTOP® PREMIUMCOAT® SYSTEM

Foundation Coat
(with fabric)

Finish Coat

Total
(Gal/Sq)

DFT*
(mils)

1st Coat
(Gal/Sq)

2nd Coat
(Gal/Sq)

10
Year

2.5

0.75

15
Year

2.5

20
Year

2.5

3rd Coat
(Gal/Sq)

System

Warranty

Total
(Gal/Sq)

DFT*
(mils)

Total
(Gal/Sq)

DFT*
(mils)

0.75

1.5

4.0

1.0

2.0

4.5

1.0

3.0

5.5

1.0

Emerald
Pledge™

Diamond
Pledge™

Yes

*DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile, application technique &
waste factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
38

QUICK SPEC

Method

• Spray, roller, or brush apply HydroStop® PremiumCoat® Finish Coat

Requirements

• The existing HydroStop® Roofing System will be inspected to determine eligibility
for recoat.
• Roof must be clean, dry, and tight.
• Adhesion test required to ensure proper adhesion to substrate(s).
• Apply at 50°F (10°C) and rising with no rain, dew, fog or freezing temperatures in
forecast for 24 hours.
• GAF recommends that the surface temperature be at or less than 110°F (43°C)
during application.

Application
Instructions

1. Roof must be inspected before work begins.
2. Ensure roof is free of dirt, debris, oil, and other contaminants that could negatively
affect adhesion.
3. Apply HydroStop® PremiumCoat® System per the chart below.

WARRANTY EXTENSION/RENEWAL
HYDROSTOP® PREMIUMCOAT® SYSTEM
Warranty
Term

Finish Coat

Warranty

1st Coat
(Gal/Sq)

2nd Coat
(Gal/Sq)

Total
(Gal/Sq)

DFT*
(mils)

10
Year

0.75

1.5

15
Year

1.0

2.0

Emerald Pledge™

Diamond
Pledge™

Yes

* DFT (Dry Film Thickness) is rounded to nearest mil. Actual DFT will vary dependent on substrate profile,
application technique & waste factor. Primer/Base is not included in DFT calculations.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
39

Quick Specs

WARRANTY EXTENSION/RENEWAL – HYDROSTOP® PREMIUMCOAT® (HS-11)

Care & Preventative
Maintenance

Section 4
Care &
Preventative
Maintenance

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
40

OVERVIEW

The roofing system is a critical asset in the overall building envelope, and should be treated as such.
Identifying and correcting potential problems early is paramount to ensuring that small problems do
not become major issues. It is also essential in maintaining the integrity of the roof, protecting the
building’s contents, and avoiding interruption of the building’s intended function. A thorough and
consistent maintenance schedule will not only extend the life of the roofing system and lower life
cycle and replacement costs, but will help protect other building components as well.

UNDERSTANDING THE IMPORTANCE OF PROPER ROOF MAINTENANCE AND REPAIR
Like all roofing systems, roofs that have been coated require regular maintenance and repair to
enhance long-term service life. The Roof Coatings Manufacturers Association (RCMA) recommends
that roofs and coatings be inspected twice each year, generally in the spring and fall, and after any
major storms or high speed wind events. Additional coating should be applied as necessary to repair
damage to the coating or underlying roofing substrate. Additional coating can also be applied where
the existing coating has worn away. Refer to the specific sections of this Manual for more information
on coating and re-coating applications.

GENERAL CARE & PREVENTATIVE MAINTENANCE
The following is a list of general care and maintenance recommendations that will help achieve
maximum performance from the roofing system.
• Provide proper drainage...to minimize standing water on the roof. Keep the roof surface
clean from leaves, pine needles, twigs, paper, accumulated dirt and other debris, which
tends to accumulate at and clog drains. Cut back trees or branches growing too close to the
roof. Ponding of water on the surface of the roofing system will increase the probability of
moisture entering the structure in the event of a puncture or other mechanical damage to
the roofing membrane.
• Check the building exterior...for settlement or movement. Cracks in the walls are a warning
of possible cracks in the roof substrate and flashing. Ensure that overhangs, cornices, fasciae,
and edging are in good condition.
• Avoid damaging the roofing system by exposing it to any of the following, which could cause
premature degradation of the coating or membrane:
• Liquids containing petroleum products
• Solvents
• Grease used for lubricating rooftop units or from restaurant vents
• Oils (new or old) used for air conditioning or compressor units
• Kitchen waste or other animal fats
• Chemicals

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
41

Care & Preventative
Maintenance

Due to its constant exposure to heat, cold, ultraviolet radiation, rain, snow, hail, high winds and/or
mechanical damage, a roof can be the most vulnerable component of a building’s exterior. Despite
these negative effects, long-term performance can be enhanced, and major roof problems avoided,
through correct design, quality materials, proper installation procedures and workmanship, and a
comprehensive roof maintenance program. The cost of a comprehensive maintenance program is
minimal compared to the cost of repairing and/or removing and replacing a damaged roofing system.

Care & Preventative
Maintenance

• The use of catch pans (including proper drainage of these pans or other means of protection)
may be used to protect the roofing membrane from exposure to grease, chemicals, and
other materials that would otherwise be expelled onto the roof surface. Prolonged exposure
to these materials can cause swelling and possible degradation of the roofing system if spills
are not removed in a timely manner.
• Check for signs of algae, mold, mildew or other plant growth on the roof, particularly in
shaded areas that hold water.
• Unprotected areas of the roofing system are more susceptible to damage from heavy foot
traffic and additional measures must be taken to avoid damage to the system. Contact
GAF at 1-800-ROOF-411 (1-800-766-3411) for recommendations where heavy foot traffic is
expected.
• If snow removal is necessary, use plastic shovels and be careful when working around
protrusions or other areas where detail work could be damaged. Snow blowers, picks, axes
and shovels with sharp edges must not be used on the roof.
• Remove foreign debris, such as glass, bolts, nails, screws, metal shavings, and any other
materials that may cause punctures or cuts to the liquid-applied coating or roofing system.
• Limit roof access. Most roof damage is caused by individuals that are not authorized to
access the roof, or by individuals that are not aware of the damage that can be caused when
proper precautionary procedures are not followed. Roof access should be strictly limited
to authorized personnel and outside personnel should be informed as to the precautions
necessary when accessing the roof. Make a log of all visitors and maintenance personnel
accessing the roof.
• Make sure that maintenance personnel are warned against dropping tools and equipment
on the coated roof surface in order to avoid puncturing the membrane. When servicing
the rooftop HVAC units, antennas, solar panels, satellite dishes, etc., care should be taken
when placing tools, metal doors, lids, pans, or sharp objects on the coating system surface.
When moving roof-mounted units or equipment over coated roofs, avoid damage by placing
smooth plywood over the coating membrane prior to moving any equipment.
• Repair of any damage caused by misuse of the roofing system is the responsibility of the
Building Owner. The Building Owner is also responsible for ensuring that any such damage
is properly repaired by either the original contractor of record or another GAF-certified
contractor. If timely repairs are not made to rectify mechanical damage or other misuse of
the roofing system, this can result in the need for major repairs or replacement of the roof or
roof coating system at the building owner’s sole expense.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
42

SEMI-ANNUAL INSPECTIONS & MAINTENANCE

Semi-Annual Inspection & Maintenance
Consist of cleaning the membrane and then a visual examination of the roof coating system. The
inspection should include the overall coating condition as well as the integrity of flashings, vent
pipes and other protrusions, skylights, drains, gutters, parapet walls and caps, adjacent walls, and
mechanical equipment. Also check for evidence of any biological growth or other foreign debris.
Preventative Maintenance Program
Consists of regularly scheduled inspections and subsequent corrective actions, intended to maximize
the life expectancy of the roofing system. It is recommended that preventative maintenance semiannual inspections be scheduled in the spring and fall.
Additional Inspections
In addition to the scheduled semi-annual inspection, additional inspections should be scheduled if
the roof is exposed to abusive or unusual conditions including but not limited to those listed below.
Maintenance programs that include semi-annual inspections can usually be arranged through the
installing contractor or another GAF-certified contractor. They can also be performed by a registered
roof consultant or other qualified personnel who have been properly trained in liquid-applied roofing
systems and safety. These inspections should be attended by the Building Owner and/or in-house
maintenance personnel responsible for the roof. Additional roof inspections should be conducted
whenever any of the following conditions occur:
1. Exposure of the roof to severe weather, such as strong winds, hail or continuous heavy
rainfall.
• Examine the roof for severely ponded areas, accumulated debris, and any damage
to building components that may allow moisture to infiltrate the roofing membrane.
The coating or liquid-applied system should also be examined in areas where severe
conditions may have caused punctures, tears, abrasions or loose coating.
2. After repair or replacement of rooftop equipment, or at any other time when the roof may
be exposed to activities from other trades where damage may occur.
• Examine the roof for spills, debris, sharp objects, punctures, excessive wear, or other
damage caused by heavy traffic or modifications to the roof.
Cleaning Procedures
WARNING: The liquid-applied roofing system or coating may be slippery when wet. Exercise caution
when walking on the liquid-applied roof system during cleaning.
1. Remove any build-up of rocks, branches, leaves, pine needles and other foreign debris,
as well as excessive dirt build-up around drains and other low areas. Use a plastic rake,
medium-bristle push brush or other appropriate method for removing accumulated debris
from the roof, using the least amount of pressure possible. Remove any excessive build-up or
blockage from drains, gutters and downspouts. Ensure that downspouts on multi-level roofs
do not dump directly onto the coated roof surface below. Trim any overhanging trees to
HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
43

Care & Preventative
Maintenance

When conducting a semi-annual inspection, the liquid-applied roofing system or coating may be
slippery when wet. Exercise caution when walking on the liquid-applied roof system or coating during
or after a rain shower, or if moisture is present in the form of dew, frost or ice. Pay attention while
walking on light-colored surfaces as ice or frost build-up may not be as visible as on a dark surface.

Care & Preventative
Maintenance

prevent excessive leaf and pine needle accumulation, allowing as much sunlight to the roof
as possible to help eliminate mildew and algae growth.
2. Liberally apply GAF United Cleaning Concentrate, diluted at a ratio of 1 part concentrate to
10 parts water, under low pressure to a given section of the roof at the rate of 0.4 to 0.7
gallons per 100 ft2 (1.6 to 2.9 L/m2). Allow the cleaner to sit for a minimum of 15 minutes.
3. Make sure that areas where algae, mold, or mildew growth has occurred are thoroughly
saturated. These areas should also receive additional scrubbing with a medium to stiff bristle
brush to assure the most complete removal possible.
4. Pressure rinse toward the drains using clean water and a 1,200 to 1,500 psi pressure washer.
Use a fan tip on the extension wand, held no closer than 12” (305 mm) from the coated roof
surface. Low areas where the dirt has accumulated may require additional agitation using a
broom or cleaning pad.
I MPORTANT: Roof wash-off catchment systems should be in place when required. Be sure to
follow state and local requirements for roof-wash off catchments during the cleaning process.

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
44

INSPECTION CHECKLIST

2. Prior to going onto the roof itself, inspect the underside of the deck (if accessible), as well
as the outside of the building. Note any signs of excessive moisture or deterioration. These
observations can give clues to not only problems with the roof, but also other conditions
affecting the performance of the building envelope.

GAF Inspection Checklist
Area of Concern

Treatment

Roof Membrane & Flashings

• Ensure that the overall roof coating membrane is sound and free
of mechanical damage, splits, crazing, and cracking. In areas prone
to standing water, inspect the coating surface for signs of blisters,
delamination, or degradation caused by biological growth.

Roof Drains & Scuppers

• Ensure that roof drains and scuppers are clear and free of all debris to
allow for proper drainage. Check drain covers to verify that they are
tight and properly fastened. Ensure that the coating around drains and
scuppers is sound and free of blisters, tears, and delaminations.

Parapet Walls & Caps

• Inspect interface between roof deck and parapet walls to ensure that
there are no splits or tears, and that the coating membrane is fullyadhered and sound. Examine parapet walls and caps to ensure that there
are no cracks or breaks in the substrate or membrane that will allow
moisture to enter beneath the coating system.

Protrusions

• Inspect the reinforced coating around all protrusions, such as vent pipes,
for any signs of splits, tears or delaminations around the base. Ensure that
vent pipes have the proper caps installed. Inspect coating to ensure that it
is still self-flashing and secure around the top of all protrusions.

Roof Mounted Equipment

• All rooftop equipment should be inspected to ensure that it is wellsecured to the base risers, and that the coating and reinforcement around
the base is sound and free of blisters, tears and delaminations.

Skylights

• Check the reinforcement around all skylights to ensure that it is sound and
free of blisters, tears and delaminations.

Other Details

• Check the bricks and mortar on chimneys, as well as caulking or joints in
metal flashings such as copings, counter-flashings, rooftop units, curbs,
caps, expansion joints, etc. Repair or replace caulking as necessary.

Moisture Analysis (optional)

• If damage has caused concern with moisture penetration into the roof
substrate, a non- destructive moisture detection survey can be conducted
to provide an accurate analysis. Two common methods are nuclear
metering and infrared thermography. A moisture meter probe can also be
inserted through the coating; however, this is a destructive method and
will require the damage be repaired.

Minor Repairs

• Areas found to need minor repairs (e.g., small punctures and tears) during
the inspection may be repaired with Roof Mate Butter Grade. More
extensive repairs may be treated with Roof Mate Butter Grade product
with fabric. For project-specific recommendations, please contact GAF’s
Technical Services.

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45

Care & Preventative
Maintenance

Pre-Inspection
1. Prior to the actual roof inspection, a detailed roof plan should be prepared, on which any
defects and notes can be recorded.

Care & Preventative
Maintenance

ROOF SPECIFIC LEAK INVESTIGATION
On metal decks, it is important to identify the direction of the deck flutes and deck slope. Moisture
may infiltrate through the roofing system, migrate in the lower flutes of the deck, and leak inside the
building in low areas.
On concrete decks or on projects where the existing roofing material is left in place, leaks may result
from moisture entrapment in the original installation.
On poorly insulated roofing assemblies, leaks may occur as the result of condensation. It is therefore
important to determine the leak location and frequency. Sources of air leakage should be sealed if
possible.
1. Begin leak investigations by conducting a thorough visual inspection of the general location
on the roof where leaks have been detected inside the building.
2. Inspect detail areas such as drains, vents, scuppers, HVAC and other roof-mounted
equipment, parapets, ponded water areas, etc. If the roof is dry at the time of investigation,
areas where water ponds can be identified by evidence of accumulated residue on roof
membrane.
3. Examine lower areas of the roof for moisture beneath the roof coating system (soft
insulation can be detected when walking over the roof).
4. Check areas around mechanical rooftop equipment, drains, skylights, roof hatches,
expansion joints, pipes, vents, etc. to identify cuts or punctures in the coating membrane.
5. Examine the condition of metal flashings (i.e., edging, coping, expansion joint covers,
parapet caps, etc.) for cracks and improperly sealed joints.
6. When a visible source of the leak has not been identified, wet the system at the anticipated
leak area with water and examine the interior area for leaks.
7. Often, an inspection of the underside of the deck will reveal signs of water leakage and/or air
infiltration.

EMERGENCY REPAIRS
GAF must be notified of any leaks within 30 days of discovery of a leak or GAF will have no
responsibility for making repairs or replacing that portion of the products that leak as a result of a
manufacturing defect. The Building Owner may make temporary repairs to minimize damage to the
building or its contents in an emergency. Only qualified workers should perform temporary repairs.
These repairs will not result in cancellation of the applicable guarantee or warranty as long as they
are reasonable and customary and do not result in permanent damage to the GAF roofing materials.
When weather conditions permit, permanent repairs should be completed by a GAF-certified
contractor at GAF’s direction if it is a covered leak or at the building owner’s direction for non-covered
leaks.
Repairs should not be made with asphalt-based products unless a wet patch type product is needed
for emergency purposes. If wet patch products are used they must be completely removed at the time
permanent repairs are made.
HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
46

• Rinse the area with clean water and allow it to dry.
• Apply HydroStop® PremiumCoat® Butter Grade Flashing and embed with fabric as needed to
provide additional strength. Contact GAF Technical Services before any other product is used
to confirm its suitability.
Specific Repairs to Liquid-Applied Roofing Systems over Spray Polyurethane Foam (SPF) Insulation
• Minor breaks in the coating or mechanical damage to sprayed polyurethane foam (SPF)
may be repaired with approved urethane caulk and then top-coated with HydroStop®
PremiumCoat® Butter Grade Flashing with or without fabric. The damaged foam must be
completely cut away prior to repairing. If the repaired area is larger than 2” (51 mm) in
diameter, consult GAF Technical Services for proper repair procedures. Note: If silicone is
used for repair, the area must be filled with Unisil with Unisil Fibers.
• Large blisters that are not leaking but have broken open should be removed and repaired. If
the blister has not broken open, GAF recommends leaving it in place.
Specific Repairs to Liquid-Applied Roofing Systems Not Over Spray Polyurethane Foam (SPF)
Insulation
• Repair minor mechanical damage to the liquid-applied coating membrane with HydroStop®
PremiumCoat® Butter Grade Flashing and/or approved urethane caulk, and then top-coated
with an approved GAF product. The damaged membrane must be completely cut away prior
to repairing. If the repaired area is larger than 2” (51 mm) in diameter, consult GAF Technical
Services for proper repair procedures.
• If the liquid-applied roofing system incorporates reinforcement fabric, then the repair should
use HydroStop® PremiumCoat® Butter Grade Flashing with or without fabric.

ROOF ALTERATIONS
General
GAF must be notified of any planned roof alterations prior to such alterations being made. Coverage
under the guarantee or warranty may be jeopardized if:
• GAF is not notified of alterations.
• The original contractor of record (or another GAF-certified contractor) does not do the
required work.
• Non-GAF products are used.
All alterations must be pre-approved, including but not limited to modifications such as roof-top HVAC
units or other equipment, pipes, satellite dishes, antennas, conduit, general penetrations, skylights,
etc.

NOTE: These maintenance and inspection procedures are provided for guideline use only. Your
GAF-certified contractor or professional roof consultant may provide a more detailed maintenance
program. Maintain records of roof damage and maintenance inspections for each building roof.
HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
47

Care & Preventative
Maintenance

Temporary Dry Surface Emergency Repairs
• Clean the coating surface around the damaged area using GAF United Cleaning Concentrate.

Architectural Design
Drawings

Section 5
Architectural
Detail Drawings

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Architectural Design
Drawings

HydroStop® PremiumCoat®
Architectural Design Drawings
Drawing Number

Substrate Specification

Page #

HS-101

Typical Metal Roof Joint Detail

HS-102

Section at Vertical Panel Seam

HS-104

Deck Joint Stripping Detail

HS-201

Standard Drip Edge Detail

HS-202

Gutter With Standard Drip Edge Detail

HS-203

Concrete Roof Deck Edge Detail

HS-300

Alternate Wall Flashing Detail

HS-301

Wall Flashing Detail

HS-302

Drip Edge Parapet Wall Detail

HS-303

Typical Roof Cant At Corner

HS-304

Typical Equipment Curb Flashing Detail

HS-305

Scupper Detail

HS-401

Curb to Curb Expansion Joint Flashing Detail

HS-502

Vent-Pipe Flashing Detail

HS-503

Vent-Stack Flashing Detail

HS-504

Standard Roof Drain Detail

HS-505

Exhaust Fan (for Cooking) Flash Detail

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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Architectural Design
Drawings

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
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�-- HYDROCAP FASTENER COVER
-FULLY EMBEDED IN PREMIUMCOAT ®
FOUNDATION COAT
�-- BEAD OF HYDROSTOP PREMIUMCOAT ®
BUTTER GRADE FLASHING
™

�--HYDROSTOP PREMIUMCOAT SYSTEM
PER SPECIFICATIONS
™

�- METAL ROOFING

IOPTION2

�---- UNICAP FASTENER COVER
,-----UNITAPE SEAM TAPE
�--HYDROSTOP PREMIUMCOAT@sYSTEM
PER SPECIFICATIONS
™

�- METAL ROOFING

!NOTE:!
1. PREPARE ALL SURFACES AS REQUIRED BY GAF SPECIFICATIONS.
2. IF RUST IS PRESENT, PRIME ENTIRE ROOF WITH STABLE RUST PRIMER@200 SF/GAL MIN COVERAGE.
3. REMOVE LOOSE OR DAMAGED FASTENERS AND REPLACE WITH FASTENERS DESIGNED TO
PENETRATE THE DECK AND SUPPORTING MEMBERS WITH NEOPRENE WASHERS AT THE SCREW HEAD.

4. METAL DECK CONFIGURATIONS MAY DIFFER FROM THE DECK PROFILE INDICATED, BUT THE
APPLICATION SHALL REMAIN THE SAME.

5. HYDROSTOP PREMIUMCOAT SYSTEM- FOUNDATION COAT, FABRIC, FOUNDATION COAT, AND FINISH
COAT COMPONENTS.
™

6. PRIMING - REFER TO HYDROSTOP™ SPECIFICATIONS FOR DECK PRIMING REQUIREMENTS.

• HYD�. SECTION AT VERTICAL PANEL SEAM
www.gaf.com
1 campus Drive
Parsippany, NJ

07054

SYSTEM

FIELD OF ROOF
SERIES

HydroStop® PremiumCoat® Liquid-Applied Roofing (LAR) – Version 1.2
51

DRAWING#

102

SCALE

ISSUE/ REVISION DATE

N.T.S.

11-1-16

Architectural Design
Drawings

loPTION 1

Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawingss

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

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Architectural Design
Drawings

NOTES

Architectural Design
Drawings

NOTES

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