Höyrynsulkumateriaalit

Höyrynsulkumateriaalit, often translated as vapor barriers or vapor retarders, are materials used in building construction to prevent or slow the movement of water vapor through walls, floors, and ceilings. Their primary function is to control moisture within the building envelope, which is crucial for preventing condensation, mold growth, and structural damage. The effectiveness of a vapor retarder is measured by its permeance, which indicates how easily water vapor can pass through it. Materials with low permeance are considered more effective vapor barriers.

Commonly used vapor retarder materials include polyethylene sheeting, kraft paper facing on fiberglass insulation, and certain types of paint. The choice of material and its placement within the building assembly depend on the climate and the specific design of the building. In colder climates, vapor retarders are typically installed on the warm side of the insulation (interior side) to prevent moist indoor air from condensing within the wall cavity. In warmer, humid climates, they may be placed on the exterior side of the insulation or omitted altogether, as outward vapor drive can be a concern. Proper installation, including sealing all joints and penetrations, is essential for the vapor retarder to function effectively.