Gluing styrofoam boards onto concrete walls (basement wall). Experiences

Hello everyone,

Does anyone have experience with gluing Styrofoam boards to concrete walls on the inside and would like to share it? The basement walls (KfW40 new building) have perimeter insulation on the outside. Now I want to additionally attach 4cm Styrofoam boards on the inside to accommodate electrical installations in them and to make the room heat up faster.
Which adhesive did you use for this and how were the boards later plastered?

Thank you very much

In advance: I have no experience. But if I were to do it, I would first check where the dew point might shift. 4cm is not that much, but it might be enough to cause a damp wall. I wouldn’t want that. Why should it be Styrofoam? What will go on top of it? Why 4cm? That’s quite a lot if something else is going on top. If I were to do it, I would use wooden slats and put wooden boards on top. But it strongly depends on the intended use.

According to the U-value calculator, there should be no condensation issue. The Styrofoam is supposed to be plastered later. And if I only took 2-3cm, it would be too little for the electrical installation. And it is supposed to become a kind of hobby or guest room. And for example, Multipor is only available at 5cm, as I have seen. And building a substructure from wood seems more complicated to me. Especially the countless holes you would have to drill into the concrete.

Our basement wall construction is done as follows. The walls facing outside are made with about 5 cm aluminum-coated styrofoam and covered with plasterboard. Since this was done by the company Schwörerhaus, I assume it has been professionally calculated. So far, 2 years after moving in, we have had no problems. You can certainly find the exact construction details on the website.

Is gluing sufficient or must it be dowelled?