Old floorboards sealed with vapor barrier - Moisture?

Good morning,

my renovation was almost 2 years ago. By chance, I came across a post last week that now made me a bit worried.

It is a house from 1960 with a basement and 2 floors. The following structure from basement to ground floor to upper floor is present. Basement to ground floor: concrete ceiling, old floorboards, new OSB panels, vapor barrier, new click vinyl. Ground floor to upper floor: Fermacell boards, insulation wool, old intermediate ceiling made of wooden beams, old wooden floorboards, new OSB panels, Aquastop impact sound insulation (not diffusion-open), new click vinyl.

With this, I have sealed the wood airtight and it can no longer breathe or release moisture, etc... and it could happen that the floorboards, worse but the beams of the intermediate ceiling, rot/decay.

Is it really necessary to remove the entire floor and the vapor barrier and is this not an actual danger?

Many thanks in advance and best regards

Hello questioner. Whether the structure cellar to ground floor "poses a danger," no one can probably predict in advance. But I agree with you that this structure, namely a cellar concrete ceiling, above it a wooden floorboard and wood-based panel construction with a vapor barrier on top, is unfortunate. Because a floorboard, but also an OSB usable layer, must be installed with ventilation behind it. That means: no vapor barrier on top if the backside (as is probably the case here) also cannot be ventilated. Whether the structure has a negative effect depends on the amount of rising water vapor. It would be unfortunate if the cellar had a so-called natural floor (rammed clay or similar) or is connected with the outside air (constant drafts, high humidity also due to, for example, low temperatures). But now to undertake a huge effort to remove the vapor barrier, I personally would not recommend it due to the considerable effort involved. Unfortunately, it means now "wait and hope." ------------------------ Best regards: KlaRa