Kosteussulkuihin

Kosteussulkuihin, also known as vapor barriers or vapor retarders, are materials used in building construction to impede the passage of moisture vapor. Their primary function is to prevent moisture from migrating through building assemblies, such as walls and roofs, where it could condense and cause damage. This condensation can lead to issues like mold growth, rot, and reduced insulation effectiveness.

The placement of a kosteussulkuihin is crucial and depends on the climate. In colder climates, it is typically installed on the warm side of the insulation, meaning on the interior of the building. This prevents warm, moist indoor air from reaching the cold exterior surfaces where it could condense. In warmer, humid climates, the kosteussulkuihin may be placed on the exterior side of the insulation to prevent humid outdoor air from entering the wall cavity and condensing on cooler interior surfaces.

Common materials used as kosteussulkuihin include polyethylene sheeting, kraft paper facings on insulation, and certain types of paints and membranes. The permeability of the material is measured in perms, with lower perm ratings indicating a greater resistance to vapor transmission. Building codes often specify the required perm rating for kosteussulkuihin based on the climate zone and building type. Proper installation, including sealing all seams and penetrations, is essential for the effective performance of a kosteussulkuihin. Incorrect installation can render the vapor barrier ineffective, or even create conditions that trap moisture.