Polybond membranes are polyester reinforced Atactic Polypropylene (APP) modified bitumen roofing products specially designed for heat-welded applications. Constructed with premium APP resins, and incorporating superior polyester reinforcing, Polybond provides an exceptionally durable roofing product which is easy to install and will provide long-term weathering performance. With a smooth surface and a polyolefin backing, Polybond exceeds all minimum ASTM standards for tensile strength, puncture resistance and flexibility. Polybond membranes can also be used as flashing membranes in all applicable specifications, in accordance with recommended installation practices.