undDampfdiffusionsbarriere

Undampfdiffusionsbarriere, often translated as vapor diffusion barrier, is a material or system designed to resist or prevent the passage of water vapor through a building assembly. Its primary function is to control the movement of moisture within walls, roofs, and floors, thereby protecting the building structure from moisture-related damage such as rot, mold growth, and deterioration of insulation.

These barriers are typically installed on the warm side of the insulation in cold climates to prevent warm, moist indoor air from condensing within the building envelope. In hot and humid climates, they may be placed on the exterior side of the insulation to achieve a similar protective effect. The effectiveness of a vapor diffusion barrier is measured by its permeance, which indicates how easily water vapor can pass through it. Lower permeance values signify a more effective barrier.

Common materials used as vapor diffusion barriers include polyethylene sheeting, foil-faced insulation, and certain types of paints or coatings. The choice of material depends on the specific climate, building design, and performance requirements. Proper installation is crucial for the barrier to function effectively, ensuring that all seams and penetrations are sealed to create a continuous barrier. Failure to do so can lead to moisture accumulation and compromise the integrity of the building.