Which wall structure is meaningfully vapor-permeable?

Hello everyone,

at the moment I am heavily involved with the topic of wall construction (vapor permeable). I am very concerned about mold growth in the house, which is why I have often read that one should tend toward a vapor permeable construction (vapor retarder instead of vapor barrier). However, when I look at the wall constructions of various manufacturers, often the barrier and not the retarder is installed (Danwood, for example). If the controlled residential ventilation fails, is mold growth then inevitable? Can someone report from experience how these (PE foil) really perform in the house? Are there wall constructions where you install the controlled residential ventilation as a nice-to-have, but it is not necessary? We currently live in an apartment and have to ventilate several times in winter so that no mold forms under the roller shutter boxes. Are there houses/walls that do not have such problems? We definitely want a ventilation system, but I do not want to have to be afraid of mold growth in the house within a few days if it fails :(

Thank you very much for your experiences

No experiments. Do it classic. No foil, no styrofoam. Use a 36.5 Ytong, plaster inside, plaster outside, done. We live without controlled residential ventilation, only with window rebate vents and Helios exhaust fan in the bathroom. No mold anywhere. Please do not put it in a plastic bag.

Ok thanks. Yes, I have that concern. Did you build it yourselves or with a company?

No matter which house you build. They are ALL airtight and have the same problems if you don't ventilate. Timber frame with foils, monolithic or with ETICS doesn't matter at all.

manages thanks to continuous ventilation through window rebate ventilators. That is an UWL = uncontrolled residential ventilation.

New houses = ventilation is important

Regarding the question: With general contractor. Everything from one source.

We definitely want to have a ventilation system, but I don't want to be afraid of mold forming in the house within a few days if it fails :(

On the one hand, there is no reason why the ventilation should fail, on the other hand, mold doesn't start immediately. If it actually happens that the power goes out for 3 or 13 days (which is somewhat unbelievable), you still have manual ventilation. Because it's not about the device itself, but about the air exchange itself. And yes: new houses are practically airtight. That's why they are nice and cozy warm.