FiberTite-FB "fleece back" membrane features an 18 x 19 / 840 x 1,000 denier weft reinforced polyester knit fabric, coated with a proprietary compound, utilizing DuPont's™ Elvaloy® Ketone Ethylene Ester (KEE) as the principle polymer in the hybrid vinyl alloy coating. The FiberTite-FB membrane incorporates a non-woven polyester felt, heat bonded to the back side of the membrane with a 3-in selvedge edge for field welding. FiberTite-FB is coated face and back with Seaman Corporation's original "KEE" formulation to provide superior hot air welding characteristics, extreme UV resistance, broad chemical resistance and long-term flexibility and reparability for the installed roofing membrane system. Additionally, FiberTite-FB exhibits superior tear, puncture, fungus, algae and flame resistance that make FiberTite Roofing Systems some of the most sustainable roofing systems available.