Are securities customary for completion and warranty?

A construction step is finished when the site manager and you say it's finished. There won't be any arguing about a missing silicone joint. That's how it should be. Our guy also wanted payment within 10 days. Ok, I say. I agree, 10 days 2% discount, 4 weeks without discount. He countered with 1%. Final payment at the end, agree on 3%. Make some concessions to him. First demand 5%, then he complains, then agree on 3%. That could work. And 3% on 200,000 is 6,000—that's something.

.... actually offers a completion guarantee on its own. However, this does not seem to be the case with most companies. At least not automatically. Should one insist on this in negotiations? Or will one then be searching forever for a suitable company because hardly anyone is willing to offer these securities? What is your experience, how far is practice on this point from reality?

Read Section 632a paragraph 3 of the Building Code.....

Cash retention is of course best.

In the event of a security claim, it is difficult to get hold of guarantees unless it is a "first call guarantee." Because without an acknowledgment from or a judgment against the construction company, the bank will not pay out (after all, the bank wants to get the money back from there). However, a guarantee document is better than nothing, especially in insolvency cases. It's just tedious to turn the guarantee into cash.

Before the final acceptance, I have already paid 99%, so what should I still withhold?

Let me try to explain the whole thing to you; this has nothing to do with your actual question or whether 99% is appropriate or not.

According to the contract, you owe 99% of the construction sum upon acceptance. So far so good. Before the planned acceptance, you should walk through the house with an expert. During this, you check whether a) the house is finished and b) free of defects. Only when a) and b) are fulfilled do you pay the 99% and then the acceptance follows. If the house is not finished, there is no acceptance and no 99%. Instead, you issue a request to the builder to finally finish the construction (with a deadline). If there are defects, you have to decide (the expert helps here) whether the defects are so severe that they oppose acceptance. Then there is no acceptance and no 99%. If they are minor defects, then you have the right to withhold double (or 2 to 3 times) the cost of defect remediation. Then you pay 99% minus 2 to 3 times the cost of defect remediation. The expert helps determine these costs. When enforcing your rights (i.e., so that the builder does not cause trouble), a specialist lawyer for construction law may help.

Even better than this theory is, of course, a payment plan favorable to you from the start. 95% is better than 99%. But in the end, it is not as important as in between. If your builder goes bankrupt at 99%, then it does not matter. At 50% shell construction and insolvency of the builder, you would have a serious problem.

... If it is minor defects, then you have the right to withhold double (or 2 to 3 times) the cost of remedying the defects. Then you pay 99% minus 2 to 3 times the cost of remedying the defects.

No. Because according to clause 6.4, among other things, this should not be possible initially (but we seriously question the effectiveness of this clause, see above). [emoji6]

Now don't confuse the questioner, this point in the [AGB] is nonsense. That does not mean, however, that you can now sign without hesitation ... Rather, it is advisable to have it reviewed and get advice from a specialist lawyer for construction law and, if necessary, to look for a contractor who is not only cheap and likeable but also offers a clean contract.

Thank you for your feedback!

The summary would be:
6.1: Installment payments until completion of the shell construction are too high. Final payment is too low.

6.4: You consider it critical, if not even ineffective.

Regarding 6.2 and 6.3, I found the following after a brief Google search.

"Completion of a trade means that the work must be largely finished. Insignificant remaining work does not affect the due date of the respective installment."
Quote: "That it should be sufficient for the due date of the installments under the agreed payment schedule that the respective construction services are only 'largely completed' is by no means compatible with the legal model of § 641 Construction Code and constitutes an unreasonable disadvantage within the meaning of § 307 para. 2 no. 1 Construction Code. Furthermore, the clause violates § 309 no. 2 Construction Code, as it constitutes an impermissible restriction of the right to refuse performance within the meaning of §§ 320, 641 para. 3 Construction Code (see Regional Court Berlin - Case No.: 26 O 166/05)"

"Progress payments are due upon receipt of invoice"
"In addition, construction contracts often contain provisions according to which a payment deadline for progress payments is generally linked to the receipt of a corresponding installment request from the contractor (contract text e.g.: 'The progress payments are due within eight days after receipt of the corresponding installment request from the contractor'). Such a provision violates the legal model of § 641 in conjunction with § 307 para. 2 no. 1 Construction Code and the equivalence principle of § 307 para. 1 Construction Code, and is therefore invalid. The respective installment request of the contractor says nothing about the construction progress and the completion of the respective performance phase. The due date of the respective progress claim can only occur once the agreed performance status has been reached. The mere sending of a payment request can therefore not lead to due date. Such contractual clauses give rise to a claim for the issuance of a cease-and-desist declaration."

There is nothing left that can be accepted as is – tomorrow might be an interesting negotiation [emoji6]