CertainTeed Membrain™ Continuous Air Barrier and Smart Vapor Retarder

MemBrain™ Continuous Air Barrier & Smart Vapor Retarder is a polyamide film that changes its permeability with ambient humidity conditions, all while providing a continuous air seal. The product’s permeance is 1 perm or less when tested in accordance with ASTM E96, dry cup method, and increases to greater than 10 perms using the wet cup method. This process allows closed building envelope systems to increase their drying potential with seasonal climatic changes. With a high resistance to water vapor in winter, MemBrain™ reacts to relative humidity by altering pore size, allowing water vapor to pass through it. When conditions change and relative humidity increases above 60%, the pores in the material expand and its permeability increases. This transformation permits drying to occur, in either direction, through the process of vapor diffusion. Thus, its lowered resistance value supports the drying process, therefore decreasing moisture accumulation within the construction and potential moisture damage. When installed with standard tape and sealing practices, it creates an air barrier that has been tested under stringent performance guidelines.
This product can be used in place of traditional vapor retarders with unfaced fiberglass insulation to provide an insulation system that is ideal in some of the more severe climate condition areas in terms of both temperature and humidity. In addition, MemBrain™ may be installed as an interior air barrier system combined with recommended tapes and sealants.

MemBrain Continuous Air Barrier & Smart Vapor Retarder is a Class A Fire Rated 2-mil thick film of polyamide (nylon).