| Modified Bitumen roof systems consist of one, two or three ply systems. The type of substrate will often determine the type of system being installed. Modified membranes can also be installed in conjunction with built-up roof materials (such as multiple plies of fiberglass felt) to form a hybrid roof system. In order to achieve proper drainage, we recommend that all modified roof systems be installed on slopes not less that 1/4" per foot. | 
