Ångskydd

Ångskydd, also known as vapor barrier or vapor retarder, is a material or membrane used in building construction to prevent or slow the passage of moisture vapor from one side of a building component to the other. This is typically achieved by installing the vapor retarder on the warm side of the insulation in cold climates. The purpose of an ångskydd is to prevent moisture from the interior of a building from migrating into the building envelope, where it could condense into liquid water. Condensation within walls, attics, or floors can lead to a variety of problems, including mold growth, rot, reduced insulation effectiveness, and structural damage.

Common materials used for ångskydd include polyethylene sheeting, foil-faced insulation, and vapor-retarding paints. The effectiveness of an ångskydd is often measured by its permeance, which indicates how easily water vapor can pass through it. Materials with low permeance are considered effective vapor barriers. Proper installation is crucial for an ångskydd to function effectively. Seams should be sealed, and penetrations through the barrier must be carefully managed to maintain its integrity. The specific requirements for ångskydd vary depending on climate zone and building codes. In warmer, more humid climates, the vapor retarder might be placed on the exterior side of the insulation or omitted altogether, as the direction of vapor drive is reversed.