Installation Guide

Technical Letter 1
Chemical Compatibility with Other
Building Materials and Sealants
Frequently during the design of an assembly, the
designer will question the chemical compatibility of
self-adhered flexible flashings with other materials.
Grace Vycor
®
Self-Adhered Flashings (Grace Vycor
Plus, Grace Vycor V40 and Grace Vycor Deck Protector) are chemi-
cally compatible with most substances and products that are
normally present in common application environments. Grace
Vycor Self-Adhered Flashings are compatible with acids, bases,
and salts.
Generally, there is no chemical compatibility issue if a material
contacts the high-density polyethylene surface of the self-adhered
flashing. If the contact area is the rubberized asphalt component of
the flashing, there is need to investigate further. As a general rule,
the material must be sound, functional and firmly bonded to the
substrate.
The design of the connection between the two materials will
vary depending on the composition of the material. Some of the
more common materials are detailed below.
Building Materials
Grace Vycor Self-Adhered Flashings are applied directly to exterior
sheathing panels such as plywood (including fire-treated plywood),
oriented strand board (OSB), exterior gypsum board, glass mat sur-
faced gypsum board, and extruded polystyrene. Grace flashings
are compatible with chromated copper arsenate (CCA), alkaline
copper quaternary (ACQ), ammoniacal copper zinc arsenate
(ACZA), pressure-treated woods and pressure-treated plywoods.
Window & Doors
The rubberized asphalt of Grace Vycor Self-Adhered Flashings is
compatible with rigid polyvinyl chloride (PVC), but not plasticized
polyvinyl chloride (flexible PVC). Some arched/round shape win-
dows may use a flexible PVC nailing flange. Consult with the
window manufacturer to determine if the nailing flange is con-
structed of flexible PVC.
Note: Per ASTM E2112, “The application of sealant to the exterior
face of the (window) flange is not necessary if using self-adhesive
type flashing over the mounting flange.”
CHEMICAL COMPATIBILITY
CHEMICAL COMPATIBILITY
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Weather-Resistive Barriers
Grace Vycor Self-Adhered Flashings are applied to the structural
substrate. They should be integrated with the weather-resistive
barrier to form water-shedding laps.
Grace Vycor Self-Adhered Flashings are compatible with the
following weather-resistive barriers:
• Spun-Bonded Polypropylene • Polyurethane Coatings
• Spun-Bonded Polyethylene • Polyethylene Sheet/Visqueen
• Red Rosin Paper • Asphaltic Dampproofing
• Asphalt Saturated Felt • Perm-A-Barrier
®
Wall Membrane
Sealant and Caulking Materials
Most sealants are chemically compatible with Grace Self-Adhered
Flashings provided that the sealant is applied to the high-density
polyethylene film component of the flashings.
The following sealants are chemically compatible with the
adhesive side of Grace Vycor Self-Adhered Flashings if the specific
formulation does not contain hydrocarbon solvents:
• Silicone • 1-Part Polyurethane
• Acrylic • 2-Part Polyurethane
• Butyl
Remove excess sealant prior to installing flashing.
Non-Compatible Materials
Grace Self-Adhered Flashings are not compatible with the
following substances:
• Creosote • Hydrocarbon Solvents
• Pentachlorophenol • EPDM
• Polysulfides • Flexible PVC
• Diesel Fuel • Uncured Neoprene
• Gasoline/Oil • High concentrations of pitch
(resin from soft wood)
Primers
Only Grace approved primers should be used with Grace Self-
Adhered Flashings. Grace Vycor Plus, Grace Vycor V40 and Grace
Vycor Deck Protector are compatible with the following Grace
primers:
• Perm-A-Barrier
®
WB Primer • Bituthene
®
Primer B2