Breather membranes (or breathable membranes) are water resistant, vapour permeable sheets or panels. Installed to protect the sheathing and frame of a building from incoming moisture, they allow water vapour from within the frame to pass into the cavity.

Timber frame breather membranes protect wall and roof structures where external cladding may not be completely water-tight or moisture resistant.

Several types of breather membrane exist and are installed on the cold side of insulation to prevent moisture (as well as snow, wind, and debris) driven through the external cladding from penetrating further into the structure. The membrane’s composition still allows the structure to be ventilated, avoiding the build-up of interstitial condensation.

I'm interested in:

• Membranes
• Moisture