APP Modified Bitumen roofing, also known as torch-on roofing, is an asphalt-based roofing system closely related to the Built-up-Roof. Modified Bitumen is designed for buildings with low-slope or "flat" roof structures. Modified Bitumen Roofing Systems are designed to withstand harsh exposure to extreme environmental elements. With five layers of protection, it's one of the most trusted flat roofing systems used today.

APP modified bitumen is asphalt combined with APP (Atactic Polypropylene), a thermoplastic polymer that gives it some plastic properties. Also called torch-on roofing, the layers of modified bitumen are merged together by a torch. Contact Matrix Roofing + Waterproofing, Inc. for more details.

When added to bitumen, APP:

• Adds flexibility to the asphalt at low temperatures

• Improves flow at high temperatures

• Increases UV resistance

APP vs SBS Modified Bitumen

Compared to SBS-modified bitumen (which has synthetic rubber added to it), the APP-modified bitumen membrane has a much higher melting point. APP also is much more UV-resistant, making it much less likely to crack or damage than SBS. Because of this, APP is the best option for flat roofs in dry and hot climates, such as Southern California.