Vapor-Bloc SA is a self-adhered vapour barrier membrane consisting of an SBS rubberized asphalt compound which is integrally laminated to a blue cross-laminated polyethylene film. The membrane is specifically designed to be self-adhered to a prepared substrate. Ideal application surfaces include steel decks, gypsum board and plywood or certain insulation panels prior to the application of finished roof coverings. The main function of Vapor-Bloc¨ SA is to serve as a full coverage vapour barrier and secondary waterproofing layer in the composition of roof assemblies.