Modified Bitumen

Polymer-modified bitumen or modified bitumen sheet membranes were developed in Europe in the early 1960s and have been in use in the U.S. since the mid-1970s. Modified Bitumen roof system membranes are composed of multiple layers, much like BUR membranes. Unlike BUR roof systems, the top or final layer of modified bitumen is a modified cap sheet that may or may not have a granulated coating.