APP Torch Base/Cap S membrane is a polyester reinforced APP modified bitumen roofing membrane designed for heat-welded (torch) applications. Constructed with premium Atactic Polypropylene resins and incorporating superior polyester reinforcing, APP Torch Base/Cap S provides an exceptionally durable roofing product which is easy to install and will provide long-term weathering. APP Torch Base/Cap S has a smooth surface and a polyolefin backing.