Gypsum plaster does not hold, too soft - tear it out yes/no? Suggestions?

Our gypsum plaster looked great so far, it was installed in the house around the end of February/beginning of March, so it had enough time to dry out, and we were also quite satisfied with our construction company Bösteinhaus until now. Now the painter inside is completely finished, and we have to realize that the paint does not adhere to the wall, although apparently everything was done correctly (primer, very good paint, professional painting company).

What do you think about this? Has anyone had similar problems? Removing all the gypsum plaster and redoing it would probably be quite difficult, right?

@schwarzmeier,

the expert calls himself a "sworn expert for painting technology and coating materials," as far as I know he is also a master painter and should be quite competent in his field. At least I chose him for that reason.

@JoS That Bösteinhaus customers paint directly onto the gypsum plaster is standard as far as I know. The show house was also painted directly. Most only equip the ceilings with painter’s fleece.

Regarding the last appointment

As an "expert," Bösteinhaus brought the sales manager of the plaster wholesaler to our first appointment. His conclusion was roughly summarized: "the plaster is fine as it is."

Why the problem occurs in 7 out of 8 townhouses could not be clarified.

We discussed the SInterhypaut issue with the expert and the builder – unfortunately without any special result. As far as I understand, our plaster consists of a very thick "SInterhypaut-like" layer that cannot be easily sanded off – but only a laboratory test can provide more details.

Tomorrow, on the advice of the company Bösteinhaus, the "technical director of the company Knauf" will come first to look at the problem. In the following blog post, you can see the Knauf silo in front of our house – it must have been just before plastering.