Blower Door Test - at which construction stage should it be conducted?

Hello everyone,

we will finally start building soon, today I received the preliminary schedule of the individual trades from the main contractor.

What confused me was the fact that the Blower Door Test was listed at the very end, about 1 calendar week before the planned acceptance. Until now, I thought you do it as soon as the building is airtight (or should be), i.e. when all windows and doors are installed and the roof is finished. Then it would also be much easier to make improvements if the test should show leaks.

Are there any specifications, DIN, etc., regarding the timing of the test?

Thank you very much in advance!

I'm not an expert, but as far as I know, the two plasters (inside & outside) also have a sealing function. They come almost at the very end, so that fits, depending on whether you have painting and flooring work included or not.

We had 2 pieces. Once after I insulated the upper floor ceiling and installed the vapor barrier. Of course, it made sense to test everything before installing the drywall. Then another one shortly after moving in. If insulation and drywall are to be removed, I think it makes the most sense to carry it out after applying the exterior plaster.

We had 2. One as soon as the building envelope was sealed. Before screed, before plaster, etc. Simply because we have to achieve a low value due to the Passive House standard. Errors can only be fixed well at that stage. A second one around the acceptance date for the KFW. The person who conducted the test said that the test is usually done only for the KFW. Many general contractors are always well below the values.

We only had one Blower Door test. Namely, after the interior plaster was applied and before the drywall sheets were installed on the upper floor, so that the foil in the roof could still be checked.