Winddicht

Winddicht, in English often translated as wind-tight or windproof, refers to the ability of a building’s envelope to resist air infiltration caused by wind and pressure differences. It is a central concept in building physics because uncontrolled air leakage affects energy use, indoor comfort, and moisture control. Winddichtheid is typically pursued as part of an airtight building envelope, but it is distinct from water tightness and drainage.

Achieving winddicht construction involves installing a continuous air barrier on the interior or exterior of the structure and properly detailing joints, seams, and penetrations. Materials such as membranes, tapes, and coatings are used to seal walls, roofs, and floors. Special attention is given to openings around windows and doors, as well as penetrations for pipes, cables, and ventilation ducts. Proper installation also requires attention to thermal bridges and connections between different elements of the envelope to minimize leakage paths.

The benefits of winddicht construction include reduced heat loss, improved energy efficiency, and fewer drafts, contributing to a more stable indoor climate. However, an airtight envelope must be paired with adequate ventilation to maintain indoor air quality and control moisture. Without ventilation, moisture can accumulate and sustain mold growth or condensation problems.

Testing and standards: Windtightness is commonly assessed using blower door tests, following standards such as ISO 9972 or EN 13829. Results are often expressed as an air leakage rate (and sometimes as air changes per hour at a given pressure, e.g., ACH50). Standards and targeted values vary by country and project type.