Construction defects and keeping the money back!!!

As is probably the case for many, we noticed some defects during the final inspection which we then recorded in writing.

The acceptance causes, among other things, the due date of the (remaining) payment.

The crucial point is whether the claims for remedying the defects were reserved despite acceptance; i.e., whether these were in a way "excluded" from the acceptance ("Ok, except for ...."). This represents an additional necessary step beyond merely recording defects in writing.

(One must also demand the remedy, which I assume here).

If applicable, retention rights (i.e., withholdings) may also be excluded according to the contract. Whether such an exclusion is effective is, in turn, another question.

Legally, it is always pretty complicated. It must be intentional on the part of the state... in any case, in your case: if you pay now, you will never get the mentioned defects repaired. Legal assistance also costs money, even though you yourself haven't really done anything wrong. The construction company has known about the defects at the latest since the handover and is probably not willing to react. As has already been mentioned to you, you will now probably have to issue a formal warning and at the same time point out that you will not pay the invoice until all defects have been resolved. At the same time, set a deadline (14 days or more) and threaten to subsequently cover the costs of rectifying the defects yourself (final invoice...). However, you cannot simply do whatever you want after the deadline. The best thing will be to wait for the inspection appointment with the boss now. They will of course tell you that it is not such a big deal, etc... however, it was recorded back then and if they become difficult, throw them out. If they then want their money, they would have to sue, and they would then have to prove that their payment demands are legitimate. You would then probably have to prove that withholding the final invoice roughly corresponds to the costs of remedying the defects. The company, on the other hand, would have to prove that the windows were installed professionally (since they want your money). Lots of ifs and buts, but the company also doesn't feel like suing. It makes more sense to come to an agreement like this.