Polyboard W is a multi-ply, semi-rigid asphaltic panel composed of a rubber-filled asphaltic core, formed between two asphalt-saturated fiberglass liners. Polyboard W is designed to be used as a base material in low-slope roofing. It may be installed over wood, concrete, rigid insulation or as a recover sheet over an existing roof surface which is to be re-roofed. Surface finishes available: Film, Release film, or Sand.