A panel for use as a substrate for a torch-down modified bitumen roof membrane is disclosed. The panel comprises a board of combustible material with a pre-applied noncombustible facer sheet. The facer sheet protects the board from burning during installation of the membrane. In a preferred embodiment,...http://www.google.es/patents/US4944818?utm_source=gb-gplus-sharePatente US4944818 - Composite roofing substrate panel
