CertainTeed MemBrain 9 ft. W X 100 ft. L Air Barrier and Smart Vapor Retarder Roll 933 sq ft

For extra protection against moisture, the MemBrain Continuous Air Barrier and Smart Vapor Retarder is your weapon of choice. It lets wall cavities dry out, to help prevent mold. In summer, when humidity is high, it increases permeability so that moisture can escape, as air tightness is maintained. In winter, when humidity is low, it continues to block moisture. Use MemBrain with un-faced insulation in place of kraft faced insulation or polyethylene. Not all climate zones require vapor retarders.