APP 170 is a heavier grade, smooth-surfaced APP modified bitumen membrane designed to be heat-welded. It consists of select asphalt, modified with atactic polypropylene, and strengthened with a fiber glass reinforced polyester nonwoven mat made with 100% recycled PET fibers. The combination results in a flexible and durable roofing membrane. APP 170 is a membrane that is strong and stable, and resistant to natural forces and other factors on the rooftop. It is ideal for both new construction and re-roofing applications as a base ply, cap sheet, or as a flashing sheet in single and multi-ply APP applications.