House acceptance with defects - how to behave?

Either I buy competence that "is on my side," or I have to further educate myself in that regard, or accept that it can happen that I do not recognize defects.

Exactly! Just take an expert for the acceptance. That certainly doesn’t cost much more, and at least everything is properly documented and you can be sure that the construction manager isn’t telling you any nonsense.

One must fairly say that the expert cannot see much during acceptance. We did this in the first construction, and the added value was limited - but so were the costs. Therefore, it was okay. It makes more sense to pay for construction supervision for the entire construction phase.

Whereas regarding KfW55 compliance, nothing can really be done anymore anyway. You have to rely on what the company states they have installed, unless everything has been properly documented with photos. Whether, for example, the insulation is approval-compliant can hardly be checked under the plaster anymore.

And even if there are photos. If I now come along and say, "You built the wrong bricks a year ago, they have a lambda of 0.12 and not 0.09." Well...

In this respect, the house will now have to be accepted as it stands, except for minor defects. I hardly believe that the general contractor will accept a retention of 40,000 EUR because the KfW stuff is not yet finalized.

But there are also plenty of builders who cannot visit the construction site often because they are building 50 or 100 km away.

And with acquiring knowledge, especially complete laymen who have never had any contact with technology and craftsmanship often completely overestimate themselves. But well...

In case of doubt, the site manager stands on the side of the general contractor. He is paid by him, he gets work from him, and in his own interest, he wants to complete his construction sites as quickly as possible.

That is the crux for the client. A layperson takes on a responsibility for which they are actually not competent. Either I purchase competence that "stands on my side," or I have to educate myself accordingly, or accept that it can happen that I do not recognize defects.

That is why I always recommend strict "separation of powers" to clients: you always hire a site manager yourself, even if the contractor uses the unprotected term to label one of his employees with the same title. Whether the site manager and construction supervisor are one or two persons is secondary – the main thing is that they are self-employed and not paid by the "opposing party."

even if the builder uses the unprotected term to label one of his employees with the same tag. Whether construction manager and construction supervisor are then one or two persons is secondary - the main thing is that they are paid by oneself and not by an "opposing party."

I think here it’s all combined in one person. Officially, there’s a different construction manager, but in fact our builder manages everything himself. However, that’s hardly worth mentioning in the forum because I think that is rather the needle in a haystack.

If I had chosen a different form of construction this time, I would have gotten an expert for the entire build. Here the relationship to the contractor is clearly in focus; I simply decided based on gut feeling. He doesn’t even give any points of attack to argue with him. He often even lets a 5e slide, in our favor. And although we were already very satisfied with the previous build, this time many things are going differently, and in several areas we positively notice how carefully the work is done.

Officially there is another site manager, but de facto our builder himself manages everything. However, this is hardly worthy of a reference in the forum, because I believe this is rather the needle in the haystack.

There are quite a few provinces where such pleasant builders "hide" - I do not primarily advise prospective builders to choose them out of motives of regional economic promotion, but because of their own profit. Such a builder is probably worth a reference - but of course not on the internet, from which he consciously keeps himself out. You do not want to unleash the ungrateful general public as future customers on someone like that.