The KEE-Stone family of thermoplastic roofing membranes now features KEE-Stone HP, which incorporates the ketone ethylene ester Elvaloy HP for flexibility, strength, and chemical and UV resistance. KEE-Stone HP is a fleece-backed thermoplastic membrane designed to serve as the cap sheet in a multi-ply hybrid system that incorporates Garland-approved modified bitumen base sheets.
KEE-Stone HP exceeds the requirements of ASTM D6754, the standard specification for KEE-based sheet roofing. The HP Elvaloy functions as a polymeric plasticizer and remains locked in the membrane even with harsh environmental exposure, helping it avoid the migration, cracking and crazing that typical liquid plasticized membranes are vulnerable to. A novel blend of fire retardants provides superior fire resistance and helps the roof achieve a 3:12 Class A fire rating for a non-combustible deck or a 2:12 Class A fire rating for a combustible deck in a hybrid assembly. The bright white surface, polymer compound and advanced chemistry resist the sun’s damaging effects and reflect UV rays away from the building for a cooler roof surface.a
