CertainTeed's most economical, torch-applied APP-modified bitumen base sheet, Flintlastic® APP Base T, is valued for its budget-friendly homogeneity with APP torch-applied cap sheets such as Flintlastic® GTA and Flintlastic® GTA-FR. Many members of the design and specification community prefer multi-layer modified bitumen roof systems constructed with the same polymer-modified material and application methodology for base and/or interply and cap sheets, to optimize stress resistance to the roof system with materials expanding and contracting at the same rate. This 80-mil membrane is manufactured with an extra strength fiberglass reinforcement, offering exceptional strength, dimensional stability and handling. Torch-down roofing technology has only strengthened since first coming on the scene in the 1970’s. CertainTeed modifies roofing asphalt with plasticizing atactic polypropylene (APP) polymers to enhance product toughness, especially in environments with elevated UV exposu...See Morere. These APP modified bitumen products are staples of the torch roofing community, especially in the West and South. Ask any experienced roofing contractor, and they will tell you that a properly installed, high-quality torch system creates a multi-layered barrier that will protect a building for decades to come. Reach out to your local CertainTeed Territory Manager to request a sample and demonstration of Flintlastic® APP Base T. See Less