Siga Majrex-200 Vapor Control Membrane
Majrex-200 is an interior use Vapor Control Layer and is perfect for use to create an air-tight membrane for climate zones requiring one.
It uses Siga's Hygrobrid technology that establishes airtight layers on the warm side of thermal insulation to prevent moisture build up in wall cavities. The membrane promotes the direction of vapor drive inward to the interior space, which aids in drying the wall assembly. This means a dryer wall assembly, and thus more likely to resist mold, rot, and damage.
Majrex-200 is considered a "smart" high performance vapor control layer, which allows vapor to pass more easily in one direction than the other. When assembled as recommended, it has a higher permeance to the interior space, which promotes vapor drying from the wall cavity/assembly inward, while having a lower permeance outward, limiting how fast vapor transports into the wall.