Masonry - Closing/filling the wall behind the underfloor heating manifold

Hello, how can a wall be "closed off" incorrectly so that it does not dry (releases moisture into the room)? Is it certain that the moisture is not coming through leaks in the heating circuit distributor and rising? Have you ever had to refill water (heating) or how is the pressure? Otherwise, XPS boards are insulation material, I would rather use plaster carrier boards / calcium silicate boards as material.

It is a new building. The heating has never been in use before, it cannot be condensate or at the distributor. I think it was because simple Styrofoam was used, then an adhesive layer that did not dry properly. And then the plaster was applied immediately on top...

I cannot answer your question concretely, but maybe it helps anyway to explain how it is solved with us: Is there (with you) a factual reason why the underfloor heating manifold disappears behind a "normal" wall? With us, instead of a wall there is only a white door, similar but nicer than the door of a fuse box, so that we always have access to the underfloor heating manifold. But maybe I am mixing something up, I am not very familiar with the technology.

I am not here to chat... sorry. But the manifold does not disappear. There is a photo attached showing how the manifold looks from the front, a door will go there. I do not need one at the back, I want to close it there. But that really has nothing to do with the topic.

The door is on the other side of the wall (see last picture).

Insert the plaster carrier board and then plaster over it.
Whether XPS also works ... probably yes, but there is definitely more suitable material for this purpose ;-)
A plasterer would probably just insert a mesh there and then machine it on.

With what "over it"? What goes there?

I would like to learn, so the question, it is not a contradiction, ;-) whether there is anything against doors on both sides?

Appearance. The content of the HKV is also mounted somewhere on it.

With what "over it"? What comes there?

Well, plaster?!

Appearance. The content of the HKV is also mounted somewhere on it. Well, plaster?!

Finish plaster? Gypsum plaster (from Rimano)? Or?

Theoretically, you can apply any plaster there.

But since you probably want to apply the same as what is already on the wall, it will probably come down to a gypsum plaster. It doesn't matter which kind of gypsum plaster. If you have too much money, a gypsum-based filler is also an option.

In the end, it will be the same as what your plasterer did. The primer can't have been so wet that the plaster stays damp for so long. If it was Styrofoam, he might have applied a kind of scratch plaster with a thin layer of adhesive. What I, for example, suggested is nothing different except that it is not Styrofoam, but a rigid foam that already has the primer on it. The main moisture is in the gypsum plaster, and if there was no other cause, the drying simply takes time. Under poor conditions, you wait for weeks (even if the weather right now doesn't suggest that).