What is substitute performance under § 887 ZPO?
Substitute performance is the enforcement of an obligation that a third party can also fulfil — a fungible act (vertretbare Handlung). In construction, that is above all the rectification of defects. Under § 887 (1) of the German Code of Civil Procedure (ZPO), the trial court of first instance authorises the creditor, upon application, to have the act performed at the debtor’s expense. § 887 (2) ZPO further stipulates that the creditor may at the same time request that the debtor be ordered to pay the expected costs in advance — without prejudice to a supplementary claim if the actual costs turn out higher.
The requirements are straightforward: an enforceable title covering a fungible act, its service on the debtor (§ 750 (1) sentence 1 ZPO), an operative part precise enough to define the defects, and the debtor being heard before the decision (§ 891 sentence 2 ZPO). The application for the advance need not be filed together with the authorisation request — it may follow later as a separate application (Federal Court of Justice, decision of 6 November 2025 – I ZB 65/25, designated for publication in BGHZ, and Higher Regional Court of Hamm, decision of 13 October 2022 – I-18 W 20/22, MDR 2023, 391).
How does § 887 ZPO differ from § 637 BGB and from the VOB/B?
These are three routes to the same goal. § 637 of the German Civil Code (BGB) lets the customer remedy the defect personally without any judgment: after the fruitless expiry of a reasonable deadline for cure, the customer may rectify the defect and claim the necessary expenses, including an advance (§ 637 (3) BGB). The VOB/B standard terms contain their own contractual substitute-performance rights after a deadline has been set — before acceptance § 4 (7) in conjunction with § 8 (3) VOB/B, after acceptance § 13 (5) no. 2 VOB/B. We explain those clauses in our VOB/B guide.
§ 887 ZPO operates at a later stage: when the duty to rectify defects has already been established by an enforceable title — usually a judgment — and still is not performed. Whoever wins a lawsuit for defect rectification enforces the judgment through § 887 ZPO.
What happened in the Kammergericht case?
By default judgment of 14 December 2023, the Regional Court of Berlin ordered a property developer (Bauträgerin) to remedy the defects, specified in the operative part, in the drainage and waterproofing of a building’s balconies and loggias. No objection was filed, the judgment became final — and the works never started. In April 2025 the creditor therefore applied for authorisation to carry out substitute performance and for a first cost advance of EUR 58,502.12 covering architect services: design and site supervision (service phases 1–3 and 5–8 of the German fee schedule for architects and engineers, HOAI).
The figures make the case remarkable. In earlier independent evidentiary proceedings (selbständiges Beweisverfahren), the court-appointed expert had estimated design and supervision costs at around EUR 5,000 — on an hourly-rate basis. The creditor demonstrated, however, that no provider on the market would take the job at hourly rates, and submitted three fee offers: EUR 58,502.12, EUR 50,166.46 (service phases 5–8 only) and EUR 64,057.11. The Regional Court granted the authorisation and awarded the full advance, and the Berlin Court of Appeal dismissed the developer’s immediate complaint (Kammergericht, decision of 17 February 2026 – 7 W 33/25, ECLI:DE:KG:2026:0217.7W33.25.00, juris). The costs of the construction works themselves will form a second advance — once the design is available. On moisture damage after acceptance, see also our article on water damage subrogation.
How does the court measure the cost advance?
Current market offers are decisive, not historical estimates. In the court’s words:
„Maßgeblich für die Vorschussbemessung sind diejenigen Kosten, die für die Ersatzvornahme der ausgeurteilten Mangelbeseitigungsmaßnahme zum Zeitpunkt ihrer Vornahme bei Inanspruchnahme marktüblicher Angebote voraussichtlich tatsächlich anfallen werden.”
“Decisive for the assessment of the advance are those costs which, for the substitute performance of the adjudicated defect rectification measure, will foreseeably and actually be incurred at the time of its execution when market-standard offers are used.”
Kammergericht, decision of 17 February 2026 — 7 W 33/25, juris — own translation
A single contractor’s estimate (Kostenvoranschlag) suffices to substantiate the amount — so the Federal Court of Justice in its decision of 6 November 2025 – I ZB 65/25, where a roofer’s estimate supported an advance of EUR 28,223.93.
The limit lies in the necessary costs within the meaning of § 788 (1) and § 91 of the German Code of Civil Procedure (ZPO): to the extent the requested advance recognisably exceeds what is necessary, it will not be awarded (Higher Regional Court of Hamm, decision of 13 October 2022 – I-18 W 20/22, MDR 2023, 391). Old expert estimates do not bind the court if no contractor is willing to work at those rates. Who has to prove the defect itself is covered in our article on the burden of proof for construction defects.
Can the debtor impose a cheaper contractor?
No. The court settled the point directly:
„Die Klägerin ist aufgrund ihrer Ermächtigung nach § 887 I ZPO berechtigt, die Architektenleistungen – ebenso wie die späteren Bauleistungen – an einen Anbieter ihrer Wahl zu vergeben, ohne insoweit an Vergabevorschläge der Beklagten gebunden zu sein.”
“By virtue of her authorisation under § 887 (1) ZPO, the claimant is entitled to award the architect services — just like the later construction works — to a provider of her choice, without being bound by the defendant’s proposals for the award.”
Kammergericht, decision of 17 February 2026 — 7 W 33/25, juris — own translation
The debtor is limited to objections against the amount of the advance — and for those he needs market-standard offers from providers actually willing to take on the specific job.
In the Berlin case, the developer had submitted a free-of-charge offer from its own designer (also its intervener), together with a HOAI fee calculation of EUR 10,878.47. The court’s answer came in two steps: a free offer is not market-standard, because it flows from the internal relationship between the developer and its designer. And it was addressed to the debtor — the creditor could not legally accept it at all. The bare HOAI fee calculation was no acceptable offer either.
Does it help the debtor to start with the design work?
No. Authorisation for substitute performance is excluded only where the debtor has already properly performed the owed act — and proper performance means successfully eliminating the cause of the defects, including the construction works. The adjudicated obligation “consists in successfully carrying out the rectification of defects and not in rendering isolated individual measures, even if these are each necessary as partial steps of a successful rectification” (Kammergericht, 7 W 33/25, juris, translation). The execution design filed during the complaint proceedings therefore changed nothing — the court did not even have to examine whether it would have enabled a proper repair.
What role does the HOAI still play?
None as a binding price frame. Since the judgment of the Court of Justice of the EU of 4 July 2019 – C-377/17 (Commission v Germany, NJW 2019, 2529), the HOAI’s mandatory minimum and maximum rates infringe Article 15 of the Services Directive 2006/123/EC. Today § 7 (1) sentence 1 of the HOAI 2021 stipulates that the fee follows the agreement concluded by the parties in text form. Objections derived from HOAI parameters — inflated eligible costs, ignored synergies — do not defeat three market offers within a comparable range.
The flip side protects the creditor: there is no need to conclude the fee agreement before the proceedings under § 887 of the German Code of Civil Procedure (ZPO). Haste would even be dangerous. “The creditor who has himself performed the fungible act incumbent on the debtor cannot subsequently claim reimbursement of the costs thereby incurred in the enforcement proceedings” (Federal Court of Justice, decision of 10 August 2006 – I ZB 110/05, juris, translation). Whoever commissions the works before authorisation is left with substantive-law claims — exposed to defences that would not exist under § 887 ZPO.
Is the advance the final word?
No, it is provisional. The final account is drawn up in the cost assessment proceedings under § 788 of the German Code of Civil Procedure (ZPO): if the advance was too low, the creditor may claim the difference (§ 887 (2) ZPO at the end), if it was too high, the surplus must be repaid. The advance decision does not fix any minimum reimbursement in the creditor’s favour.
What matters in practice is liquidity. The decision is immediately enforceable, because the immediate complaint carries no suspensive effect in this constellation (§ 570 (1) ZPO). The court may suspend enforcement (§ 570 (2) and (3) ZPO), but that remains the exception — in the Berlin case, the interim stay issued by the Court of Appeal (a so-called Hängebeschluss) lasted only until the Regional Court had ruled on the suspension request, and was not extended.
What does this mean for the employer (creditor)?
First: a precise operative part. The defects must be described in the title exactly enough to be enforceable — this is something to secure at the complaint stage. Second: current offers for the specific scope, including design and site supervision. For waterproofing works, supervision belongs to the recoverable costs, as these are particularly damage-prone trades (Kammergericht, judgment of 8 December 2005 – 4 U 16/05, as cited in 7 W 33/25). Third: no commissioning before authorisation — otherwise the enforcement-law reimbursement claim is lost (Federal Court of Justice, I ZB 110/05). Fourth: the advance may be staged — architect costs first, construction costs after the design. And for titles from interim proceedings: the application under § 887 (1) ZPO must be filed within the one-month period of § 929 (2) ZPO, otherwise the injunction becomes unenforceable (Federal Court of Justice, decision of 6 November 2025 – I ZB 65/25).
What does this mean for contractors and developers (debtors)?
Above all: never sit out a default judgment. The Berlin case began with a default judgment left unchallenged. Once the title exists, the only safe defence is complete rectification of the defects before the court grants the authorisation — designs, expert reports and announcements are not enough. The amount of the advance can only be attacked with a market-standard offer from a third-party provider willing to take over the specific job — courtesy offers from affiliated companies are disregarded. An overpayment only returns after the account under § 788 of the German Code of Civil Procedure (ZPO), and until then the money is tied up. The immediate complaint (§ 793 ZPO) does not stop enforcement by itself — suspension (§ 570 (2) and (3) ZPO) is the exception.
Documents for the application under § 887 ZPO
Prepare the enforceable title with proof of service (§ 750 (1) ZPO). Attach the demand letter to the debtor with proof of the fruitless deadline. Document the outstanding defects — inspection report, photos, private expert opinion. Collect two or three current offers or estimates for the specific scope, covering design and supervision. Finally, calculate the requested advance, staged if appropriate.
Frequently asked questions
Does the creditor have to pre-finance the substitute performance?
No. § 887 (2) ZPO grants a claim to advance payment of the expected costs before any costs arise. If the advance proves insufficient, a supplementary claim remains.
Can the advance exceed an earlier expert estimate?
Yes. Market offers at the time of the substitute performance are decisive. In case 7 W 33/25, an estimated EUR 5,000 became EUR 58,502.12 because nobody would work at the expert’s rates.
Can the debtor still remedy the defects after the application is filed?
Yes — complete and proper rectification before the authorisation excludes substitute performance. Partial steps such as an execution design are not enough (Kammergericht, 7 W 33/25).
Is a single estimate sufficient?
For substantiating the amount, yes (Federal Court of Justice, I ZB 65/25). Several comparable offers, however, strengthen the market character of the price — the Berlin case featured three.
Does § 887 ZPO also apply to interim injunctions?
Yes, but the enforcement application must be filed within the one-month period of § 929 (2) ZPO. After that, the injunction ordering the act becomes unenforceable (Federal Court of Justice, I ZB 65/25).
What if the substitute performance turns out cheaper than the advance?
The surplus must be repaid to the debtor. The final account is drawn up in the cost assessment proceedings under § 788 ZPO.
Basis: decision of the Kammergericht of 17 February 2026 – 7 W 33/25 (juris). This article is for information purposes only and does not replace legal advice in an individual case.