Controlled residential ventilation: Is an air gap under the doors required?

If it works the way you describe with [Kontrollierte-Wohnraumlüftung], why then all the fuss about shortening door leaves?
Right, Sebastian, I didn't want such a huge gap either.

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Yes, I also don’t know what the problem is...our door leaves are not shortened...frames fully foamed...maximum 5mm gap present yet the controlled residential ventilation works perfectly...

What kind of gaps do you have under the door? For us, it's a maximum of 5mm, if not even less.


There is even a plastic edge under the door as far as I can see.

And the frame is sealed with silicone towards the tiles. I think it looks better like that than without.

If there really is a rubber lip there, it would be pretty poorly planned for a controlled residential ventilation system.

It is plastic, just checked again, presumably to protect the bottom edge of the door, for example, against water.

Did you do it yourselves? And in that area you don’t have any expanding foam or anything, but it is really open? How satisfied are you with your solution?

Milled out with the router. Goes very quickly and in my opinion has no noticeable impact on stability. There is no expanding foam up there, as we only insulated the doors at specific points. I wouldn’t see any advantage in foaming the frames completely, since they already hold very firmly like this. Satisfied? I certainly can’t detect any difference in sound transmission compared to the same doors without this overflow opening in the basement.