When this author joined the roofing industry toward the end of 1999, the standard for modified bitumen (mod-bit) sheets was Canadian General Standards Board (CGSB) 37-GP-56M, Membrane, Modified, Bituminous, Prefabricated, and Reinforced for Roofing; the National Building Code of Canada (NBC), along with many provincial codes, was referencing it in Sections 5 and 9.