ᐅ Gypsum plaster isn’t adhering well and feels too soft – should I remove it or not? Any suggestions?

Our gypsum plaster looked great so far. It was installed around the end of February/beginning of March, so it had enough time to dry out, and we have been quite satisfied with our construction company Bösteinhaus until now. The interior painter has now completely finished, but we have to find that the paint does not adhere to the wall, even though everything seems to have been done correctly (primer, high-quality paint, professional painting company).

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

Actually, you seem to be quite far along in identifying the root cause, if I understand your blog correctly.

In my opinion, it is essential to stop all further trades until the issue is clarified and the defects are rectified. Has the handover of the house already taken place, presumably? Has the final payment been made?
You have scheduled a meeting with the general contractor, so attend it together with the expert assessor and then decide on the next steps.
Sorry, but there doesn’t seem to be anything positive to say about this.

I’m keeping my fingers crossed and, based on my own experience from 16 years ago, I strongly recommend not making any compromises on the quality of the workmanship due to time pressure. You will regret it every single day afterwards.

A quick follow-up – was your planned decorative paint directly on gypsum plaster communicated to the general contractor? Was this agreed upon? I believe there might have been an option to apply, for example, cement render. Well, I’m curious to hear what the experts will say about it starting tomorrow.

brgmn schrieb:
Our gypsum plaster looked great so far; it was delivered to the house around late February/early March, so it had enough time to dry out, and we have been quite satisfied with our construction company Bösteinhaus up to now. Now the interior painter has completely finished, and we have to find that the paint does not adhere to the wall, even though everything was apparently done correctly (primer, very good paint, professional painting company).

What do you think? Has anyone experienced similar problems? Tearing out all the gypsum plaster and redoing it would probably be quite difficult, right?

What is the expert’s profession?
Just from what I can tell as a master painter and expert by looking at a photo, the gypsum plaster’s surface has a significant amount of sinter skin, which needs to be removed mechanically or chemically to provide a proper substrate for painting. Not even the best primer will help otherwise.

@schwarzmeier,

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

@JoS As far as I know, Bösteinhaus customers typically apply paint directly onto the gypsum plaster. The show home was also painted directly. Most only cover the ceilings with painter’s fleece.

Regarding the last appointment

As an "expert," Bösteinhaus brought along the sales manager from the plaster wholesaler to our first meeting. His summary was roughly: "the plaster is fine as is."

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

We discussed the “sInterhypaut” issue with the expert and the builder—unfortunately without any conclusive results. From what I understand, our plaster consists of a very thick "sInterhypaut-like" layer that cannot be easily sanded off—only a laboratory analysis could provide more details.

Following Bösteinhaus’s recommendation, the "technical manager from Knauf" will come tomorrow to inspect the problem. In the following blog post, you can see the Knauf silo in front of our house—it must have been shortly before the plastering.

brgmn schrieb:
@schwarzmeier,

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

@JoS As far as I know, Bösteinhaus customers paint directly onto the gypsum plaster as standard. The show home was also painted directly. Most only apply painter’s fleece on the ceilings.

Regarding the last appointment

As an "expert," Bösteinhaus brought the sales manager of the plaster wholesaler to our first meeting. His summary was roughly: "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 contractor—unfortunately without any significant results. From what I understood, our plaster consists of a very thick "SInterhypaut-type" layer, which cannot simply be sanded off—a more precise statement can only be made by laboratory testing.

Following the advice of Bösteinhaus, the “technical director of Knauf” will come tomorrow to inspect the issue. In the following blog post, you can see the Knauf silo in front of our house—it must have been just before plastering.

This is the first time I’m hearing that a plaster can contain a very thick SInterhypaut layer. Apparently, you never stop learning. I don’t mean to offend the expert, but since SInterhypaut is very thin, it can chemically be broken up by fluorination, thus enabling adhesion for painting applications. One learns this in vocational school.