Moisture problem in interior plaster after exterior insulation using VWS

Hello,

we are currently working on a rough construction site schedule and have come across a question. We plan to insulate the exterior facade with 25cm ETICS (classic polystyrene boards) immediately after the outer walls, roof, and window installation. (The advantage is that, first, we only need to set up the scaffolding once and we do not have problems with drying time in winter.) Now to my question: If we then plaster the interior walls afterward, can the moisture introduced during this process still escape well when the external wall already has the full thermal insulation installed? The same applies to the screed laid afterward.

Thank you very much for your information and answers.

Best regards Stefan

It depends on the temperatures inside and outside

And what humidity inside and outside.

My recommendation: ventilate sensibly, ventilate and ventilate again. Both during the construction phase and afterwards (if no technology takes over).

The plan is to apply the VWS from early October to early November this year and then probably plaster the interior walls from spring to summer. Moisture from the inside (i.e., interior plaster) that cannot dissipate outward through the VWS – is constant ventilation sufficient for this?

Constant ventilation is not necessarily sensible ventilation. Ventilate x times daily, and always when the actual moisture content (not relative humidity) inside is greater than outside.

Ever thought about the screed? With stress heating you could keep chimpanzees and tropical frogs.

By the way, summer is not necessarily optimal for drying. Early spring would be better when it is still cold/cool.

And yes, ventilating 6-8 times a day is enough.

Moisture from the inside (i.e. interior plaster) which cannot escape outward through the ETICS - is constant ventilation sufficient in this case

Even without ETICS, the moisture cannot escape through the walls. Only heating and ventilation help, and as already mentioned, preferably not in summer.