Long-term effectiveness – tested and confirmed
Humidity-variability has to work reliably in the long term
The durability of humidity-variable vapour retarders and airtight membranes needs to be tested and confirmed – this has been stipulated by the German wood preservation standard DIN 68800-2 since 2012. This standard has been adopted by the construction inspection authorities in Germany, which means it is not just a recommendation, but instead forms part of building law and is thus legally binding. DIN 68800-2 explicitly demands verification of the ageing behaviour of vapour retarders with humidity-variable diffusion resistance.
This verification can be provided in the form of a European Technical Assessment (ETA), for example.