Instructions / Assembly

Quick Specs
HydroStop® PremiumCoat® Liquid-Applied Roong (LAR) – Version 1.3
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PROPER PREPARATION FOR ROOF TYPES
To ensure proper coang applicaon, the exisng roof membrane must be thoroughly cleaned. All
dust, chalking lm, bitumen exudate, greases or oils, and other loose debris should be removed
prior to coang. Be careful when pressure washing to preserve the integrity of the exisng roof
membrane and to avoid damage to membrane seams (especially adhered seams). Allow the roof to
dry completely prior to coang. Any required roof or ashing repairs should be completed and allowed
to adequately cure where necessary. Refer to specic secons of this Manual for more informaon on
roof preparaon.
Depending on type of exisng substrate and the coang to be applied, use of a primer may be
required. Surfaces which typically require primer include: metal ashings, gravel stops, and other
metal edging; concrete roof decks, masonry walls and other oor surfaces, and other porous surfaces.
Refer to specic secons of this Manual for detailed requirements.
While rusted metal roofs can be coated, addional measures may be required. If the roof is aected by
“white rust” (i.e., zinc or aluminum), it can be coated aer cleaning. However, if the roof is aected by
“red rust,” the rust must either be removed or treated with corrosion inhibing primer. Addionally, all
rusted fasteners should also be removed or treated with a corrosion inhibing primer.
GENERAL SUBSTRATE CONDITIONS
Preparaon of the roof substrate is the responsibility of the installer, who must address and correct all
of the condions listed in this secon.
• Examine substrates to receive new roong. If any quesons arise regarding the compability of
HydroStop® PremiumCoat® liquid-applied roofing products with an exisng substrate, Installer
shall prepare test patches to check adhesion.
• Do not proceed with the installaon of the HydroStop® PremiumCoat® liquid-applied roofing
system unl compability and adhesion of HydroStop® PremiumCoat® roofing system has been
veried by test patches and other preparatory work has been completed and unsasfactory
condions have been corrected.
• Roof must have posive drainage. Substrate should not pond water for more than 48 hours aer
precipitaon stops.
• GAF denes “ponding” as water that does not drain or dissipate from the roof surface within
48 hours aer precipitaon ends. Ponding can also result from other water sources, including
improperly piped air condioning condensate and steam condensate lines.
• Protect adjacent surfaces that will not be coated.
• Do not apply liquid-applied roong products to surfaces unacceptable to GAF, or under inclement
environmental condions.
• Substrates must be clean, completely dry, and free of any debris before applicaon of any liquid-
applied products.
• HydroStop® PremiumCoat® liquid-applied roofing products should not be used on heavy-trac
bearing substrates. If foot trac is expected, a rooop walkway system approved by GAF must be
used.
Always contact GAF’s Technical Services Department (800-766-3411) for quesons regarding suitable
substrates, materials for test patches, or if you require addional informaon.
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.