May I simply instruct another firm if the subcontractor does not deliver?

Not without more. Reimbursement of the necessary expenses under § 637 Abs. 1 BGB requires that you first set a reasonable deadline for subsequent performance and that it expired without result. If you instruct someone beforehand, you generally bear the additional costs yourself — that is the most common and most expensive mistake in this situation. Only in the event of a serious and final refusal is the deadline unnecessary under § 637 Abs. 2 BGB.

Do I have to pre-finance the remedying of defects?

No. § 637 Abs. 3 BGB gives you a right to an advance payment for the necessary expenses. Demand it expressly and quantify it — usually supported by two to three quotes. The advance must be accounted for later.

What changes if the VOB/B has been agreed?

Then the case follows a different path. Before acceptance, § 4 Abs. 7 VOB/B applies: the firm carrying out the work must remedy defective work at its own expense; if it refuses to do so after a deadline has been set, withdrawal of the order under § 8 Abs. 3 VOB/B may be considered. After acceptance, § 13 Abs. 5 VOB/B applies. You should therefore first check whether the VOB/B has been validly incorporated.

The subcontractor is just too slow, nothing is defective. Does § 637 BGB apply then too?

No, that is the other case. As long as the work is not yet finished, the issue is not rights for defects but default: you set a reasonable deadline for completion and can then claim damages in lieu of performance under § 281 BGB — which include the additional costs of a replacement contract. The rights for defects under § 634 BGB together with § 637 BGB generally apply only from acceptance.

Can I set off the additional costs against the security retention?

As a rule yes, but the conditions for set-off must be met and any guarantee must cover the claim. An unjustified retention puts you in default yourself and can trigger claims of the subcontractor. You should therefore list the items separately and in a verifiable way.

SMBs & agencies · Subcontractor not delivering

Subcontractor fails to finish — self-remedy under § 637 BGB

The site is at a standstill, the subcontractor does not respond — and your own client is waiting. Before you instruct another firm, a deadline determines who bears the costs.

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Deadline at a glance

Reasonable additional deadline — before instructing any third party

§ 637 Abs. 1 BGB

There is no fixed statutory deadline in days. What matters is that you set a reasonable deadline for subsequent performance and wait for it to expire without result before instructing a third-party firm. Only in the cases of § 637 Abs. 2 BGB — in particular a serious and final refusal — is setting a deadline unnecessary.

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Typical risks in this scenario

What we pay special attention to

Curated from real cases. The AI review flags exactly these points in your document.

A third-party contractor was commissioned before the additional deadline had expired — reimbursement of costs under § 637 Abs. 1 BGB requires that a deadline was set without success.
Delay and defect mixed up: before acceptance, the claim to performance is in the foreground; the warranty rights under § 634 BGB generally only apply afterwards.
VOB/B not checked — then § 4 Abs. 7 VOB/B (before acceptance) and § 13 Abs. 5 VOB/B (afterwards) apply instead of the BGB route.
Termination for good cause without a sound reason: it is treated as a termination for convenience (§ 648 BGB) — you then owe the full remuneration less expenses saved.
Substitute performance destroys the evidence: without prior documentation or independent evidentiary proceedings (§ 485 ZPO), you bear the risk of proof.
No advance payment demanded under § 637 Abs. 3 BGB, and the remedial work pre-financed out of your own pocket.
The subcontractor's work has already been accepted without reservation — rights regarding known defects are lost (§ 640 Abs. 3 BGB).
Additional costs not set off against the security retention and the outstanding final invoice, although set-off was possible.

What you can do here in 5 minutes

If you instruct a third-party firm before a reasonable deadline has expired without result, you are regularly left to bear the additional costs — that is the most expensive mistake in this situation. The law distinguishes two cases that proceed entirely differently: if the work is not yet finished, the issue is default (Verzug) and damages in lieu of performance (§ 281 BGB). If it is finished but defective, the rights for defects under § 634 BGB apply and with them self-remedy (Selbstvornahme) under § 637 BGB — including a right to an advance payment, so that you do not have to pre-finance the remedying of defects (§ 637 Abs. 3 BGB). If the VOB/B has been incorporated, a third path applies.

Upload the subcontract, the bill of quantities, your list of defects and the correspondence — we classify the case as default or as a defect, check whether the VOB/B path applies, draft the notice with a deadline and an announcement of self-remedy, and structure the statement of additional costs.

How it works

Results in three steps

Upload your documents

Subcontract, bill of quantities, list of defects, correspondence.

Classify the case

Default or defect? BGB or VOB/B? The deadline and the legal basis of the claim depend on this.

Set a deadline and announce

Notice with a specific date, a demand for an advance payment and an announcement of self-remedy.

What you get

Upload your documents – Subcontract, bill of quantities, list of defects, correspondence.
Classify the case – Default or defect? BGB or VOB/B? The deadline and the legal basis of the claim depend on this.
Set a deadline and announce – Notice with a specific date, a demand for an advance payment and an announcement of self-remedy.

What it is not

No technical assessment of whether a defect exists or which repair is needed — an expert clarifies that.
No statement of how many days a reasonable deadline has; that depends on the trade, the stage of construction and the season.
No check whether the third-party firm's prices are usual in the locality and therefore necessary within the meaning of § 637 Abs. 1 BGB.
No preservation of evidence and no representation in independent evidence proceedings or in court.

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Before you terminate the subcontract or withdraw the order (§ 648a BGB, § 8 Abs. 3 VOB/B), if you face a contractual penalty under your own construction contract, if the subcontractor shows signs of insolvency or if independent evidence proceedings are in prospect, you should involve a lawyer specializing in construction and architects' law.

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