Purpose
In works contract law, a single point in time decides almost everything: the acceptance. It brings about maturity of the remuneration, transfer of risk, reversal of the burden of proof to the detriment of the customer, and commencement of the limitation period. This skill first determines the acceptance status — including the often overlooked fictional acceptance pursuant to § 640 para. 2 BGB — and then works through the catalogue of rights under § 634 BGB as well as the termination rights.
Inputs
- Contract type: general works contract, construction contract (§§ 650a ff. BGB), consumer construction contract (§§ 650i ff. BGB), architect/engineer contract (§§ 650p ff. BGB), developer contract (§§ 650u, 650v BGB); VOB/B included?
- Description of services, remuneration (flat rate / unit prices / hourly wage), completion date
- Acceptance status: formal acceptance, implied acceptance, refusal of acceptance, notice of completion with date
- Description of defect; materiality; reservation declared upon acceptance?
- Deadlines already set, payments, installment payments (§ 632a BGB), securities
- In case of intent to terminate: reason for termination, services already rendered, expenses saved
Sub-agent architecture
- Researcher (
../../agents/researcher.md) supplies statutes (BGB works contract law, if applicable VOB/B as general terms and conditions), commentary passages (Messerschmidt/Voit, Kniffka/Koeble, MüKoBGB) and case law with verification marker. - Drafter (
../../agents/drafter.md) examines acceptance → defect → catalogue of rights → setting of a deadline → secondary rights → limitation → termination and drafts notice of defects, setting of a deadline and termination. - Reviewer (
../../agents/reviewer.md) examines effects of acceptance, limitation § 634a BGB, written form of termination (§ 650h BGB) and source markers.
Procedure
1. Contract typology and applicable regime (§ 631 BGB)
The works contract owes a result, not merely an activity — delimitation from the service contract (§ 611 BGB) and from the purchase contract with an installation obligation. Check in sequence whether one of the special regimes applies:
- Construction contract §§ 650a ff. BGB: construction, restoration, removal or conversion of a structure — with right of instruction § 650b BGB, remuneration adjustment § 650c BGB, determination of condition § 650g BGB, written form of termination § 650h BGB.
- Consumer construction contract §§ 650i ff. BGB (see no. 7).
- Architect and engineer contract §§ 650p ff. BGB with target-finding phase and special right of termination § 650r BGB.
- VOB/B: applies only upon effective inclusion; vis-à-vis consumers, the VOB/B as a whole is subject to the content review under §§ 307 ff. BGB.
2. Acceptance (§ 640 BGB)
The customer is obligated to accept the contractually compliant to accept the work. He may not refuse acceptance on account of insignificant defects (§ 640(1) sentence 2 BGB).
Effects of acceptance:
- Due date of remuneration (§ 641(1) BGB)
- passing of risk (§ 644 BGB)
- Reversal of the burden of proof for freedom from defects to the customer
- Commencement of the limitation period for defect claims (§ 634a(2) BGB)
- Loss of defect rights upon acceptance without reservation despite knowledge of the defect (§ 640(3) BGB) — Record reservation at acceptance
3. Fictitious acceptance (§ 640(2) BGB)
A work is also deemed accepted if the contractor, after completion of the work, has set the customer an reasonable period for acceptance and the customer has not refused acceptance within this period by stating at least one defect .
- If the customer is a consumer, the effects of fictitious acceptance occur only if the contractor, together with the request for acceptance, has pointed out to him the consequences of acceptance not declared or refused without stating defects in text form (§ 640(2) sentence 2 BGB).
- For the contractor this is the fastest route to the due date; for the customer the most common trap. A single named defect is sufficientto prevent the fiction — it need not be material and need not be justified.
Suggested wording (contractor side): “The services under the contract dated [date] have been completed as of [date]. I hereby request acceptance by [date] . Notice pursuant to § 640(2) sentence 2 BGB: If you do not declare acceptance by the stated date and do not refuse it by stating at least one defect, the work shall be deemed accepted upon expiry of the period."
4. Catalog of rights in the event of defects (§ 634 BGB)
| No. | Right | Norm |
|---|---|---|
| 1 | Subsequent performance | § 635 BGB — Contractor's right of choice between removal and new production |
| 2 | Self-performance and reimbursement of expenses | § 637 BGB |
| 3 | Withdrawal / reduction | §§ 636, 323, 326(5) BGB / § 638 BGB |
| 4 | Damages / reimbursement of expenses | §§ 280, 281, 283, 311a BGB / § 284 BGB |
Note the difference from sales law: The right of choice in subsequent performance lies with the contractor (§ 635(1) BGB), not with the customer. A defect exists if the work does not have the agreed quality or is not suitable for the presupposed or customary use (§ 633 BGB); this also includes the recognized rules of technology.
5. Self-remedy and advance payment (§ 637 BGB)
After the fruitless expiry of a reasonable period for subsequent performance, the customer may remedy the defect himself and demand reimbursement of the necessary expenses (§ 637 para. 1 BGB). The period is unnecessary if the contractor justifiably refuses subsequent performance as well as in the cases of § 636 BGB.
Practically decisive is § 637 para. 3 BGB: claim to advance payment. The customer may demand from the contractor an advance payment for the expenses necessary to remedy the defect. He therefore does not have to pre-finance the remediation. The advance payment must be settled after implementation accounted for; unused amounts must be repaid.
6. Limitation (§ 634a BGB)
| Work | Period | Start |
|---|---|---|
| Building; planning or supervisory service for this | 5 years | Acceptance |
| Work whose success consists in the manufacture/maintenance/alteration of an item or in planning services for this | 2 years | Acceptance |
| Other works (e.g. incorporeal results) | Standard limitation §§ 195, 199 BGB | End of the year of knowledge |
| Fraudulent concealment | Standard limitation, but at least the above period | § 634a para. 3 BGB |
Without acceptance, the limitation period does not begin — the contractor can still be claimed years later if he never brought about acceptance.
7. Consumer building contract (§§ 650i et seq. BGB)
A consumer building contract is the contract by which the contractor is obligated by a consumer to construct a new building or to carry out substantial conversion measures on an existing building. Duties of the contractor:
- Building description in text form before conclusion of the contract (§ 650j BGB in conjunction with Art. 249 EGBGB), with binding information on the completion date (§ 650k para. 3 BGB)
- Text form of the contract (§ 650i para. 2 BGB)
- Instalment payments at most 90 % of the total remuneration (§ 650m para. 1 BGB), security for timely completion 5 % (§ 650m para. 2 BGB)
- Surrender of documents § 650n BGB
Right of withdrawal (§ 650l BGB): The consumer has a right of withdrawal under § 355 BGB, unless the contract was notarised. The contractor must inform about the right of withdrawal under Art. 249 § 3 EGBGB. The period is 14 days; without proper instruction it is extended — calculation via /vertragsrecht:verbraucherwiderruf. The §§ 650i et seq. BGB are not waivable (§ 650o BGB).
8. Termination: free termination (§ 648 BGB)
The customer may, until completion of the work, at any time and without reason terminate. Legal consequence: The contractor retains the claim to the agreed remuneration, but must credit against it what he saves in expenses as a result of the termination of the contract or acquires through other use of his labor or maliciously fails to acquire. It is presumedthat he is entitled to 5% of the remuneration attributable to the part of the work not yet performed (Section 648 Sentence 3 of the German Civil Code). The contractor must account for the saved expenses in a verifiable manner.
9. Termination: Termination for good cause (Section 648a of the German Civil Code)
Both parties to the contract may terminate for good cause without observing a notice period if continuation of the contractual relationship until completion is unreasonable for the terminating party. Partial termination is also possible Partial termination of a separable part of the work (Section 648a Paragraph 2 of the German Civil Code). After termination, each party may demand a joint determination of the status of performance (Section 648a Paragraph 4 of the German Civil Code); if one party refuses to cooperate, that party bears the burden of proof for the status of performance. The contractor may only demand remuneration for the performed up to termination services (Section 648a Paragraph 5 of the German Civil Code).
For construction contracts, termination requires written form (Section 650h of the German Civil Code) — text form or email is not sufficient.
Sources
Statutes
- Section 631 of the German Civil Code, Section 632a of the German Civil Code, Section 634 of the German Civil Code, Section 634a of the German Civil Code, Section 637 of the German Civil Code, Section 640 of the German Civil Code, Section 641 of the German Civil Code
- Section 648 of the German Civil Code, Section 648a of the German Civil Code
- Section 650i of the German Civil Code, Section 650l of the German Civil Code, Section 650u of the German Civil Code, Section 650v of the German Civil Code
- Section 323 of the German Civil Code, Section 280 of the German Civil Code
Commentaries
- Busche, in: MüKoBGB, 9th ed. 2023, Sections 631, 640, 648 paras. 1 et seq.
[unverifiziert – Auflagenstand prüfen] - Messerschmidt/Voit, Private Construction Law, 4th ed. 2022, Section 640 of the German Civil Code paras. 1 et seq.
- Kniffka/Koeble/Jurgeleit/Sacher, Compendium of Construction Law, 5th ed. 2020, Part 4 (Acceptance) and Part 6 (Defect Rights)
Case Law
- German Federal Court of Justice, judgment of 22.02.2018 – VII ZR 46/17 (no "fictitious" defect remediation expense as damages in a contract for work)
[unverifiziert – prüfen] - German Federal Court of Justice, judgment of 25.02.2016 – VII ZR 49/15 (advance claim under Section 637 Paragraph 3 of the German Civil Code, duty to account)
[unverifiziert – prüfen]
Both case numbers must be verified in juris / Beck-Online before use. The substantive statements of this skill follow from the wording of the statute.
Output format
WERKVERTRAG / MÄNGEL — <Bauvorhaben / Werk> — <Datum>
I. Vertragstyp [Werkvertrag / Bauvertrag / Verbraucherbauvertrag / Architektenvertrag]
VOB/B einbezogen: [ja / nein]
II. Abnahme (§ 640) [erfolgt am <Datum> / verweigert / fiktiv § 640 II]
Vorbehalt erklärt: [ja / nein — Folge § 640 III]
III. Mangel (§ 633) [✅ / 🟡 / ❌ — Beschreibung]
IV. Nacherfüllung (§ 635) [verlangt am <Datum>, Frist bis <Datum>]
V. Selbstvornahme (§ 637) [möglich / Vorschuss § 637 III: <Betrag> EUR]
VI. Rücktritt / Minderung [§§ 636, 323 / § 638 — Betrag]
VII. Schadensersatz (§§ 280, 281) [dem Grunde nach / Höhe]
VIII. Verjährung (§ 634a) [2 / 5 Jahre — Ende: <TT.MM.JJJJ>]
IX. Verbraucherbauvertrag [N/A / §§ 650i ff. — Widerruf § 650l bis <Datum>]
X. Beendigung [§ 648 frei / § 648a wichtiger Grund / keine]
Schriftform § 650h beachtet: [ja / nein / N/A]
Empfohlene nächste Erklärung: <…> bis <Datum>
Gesamtbefund: [🟢 / 🟡 / 🔴]
Offene Tatsachen: <Liste>
Risks / typical mistakes
- Overlooking fictitious acceptance — the customer allows the acceptance period to expire without naming at least one defect; as a result, the remuneration becomes due and the burden of proof shifts (Section 640 Paragraph 2 of the German Civil Code).
- Forgetting to reserve rights upon acceptance — anyone who accepts a work without reservation despite knowing of a defect loses subsequent performance, withdrawal, reduction and damages (§ 640(3) BGB).
- Right of choice in subsequent performance confused — in a construction contract the contractor chooses the type of subsequent performance (§ 635(1) BGB), unlike in sales law.
- Advance payment § 637(3) BGB not claimed — the client unnecessarily pre-finances the remedial work and bears the contractor's insolvency risk.
- Termination of a construction contract by email — § 650h BGB requires the written form; otherwise the termination is void as to form (§ 125 BGB).
- Limitation period § 634a BGB misapplied — it begins with acceptance, not with completion; without acceptance it does not run at all.
- Consumer construction contract without cancellation instructions concluded — the cancellation period under § 650l BGB then does not begin, and the consumer can cancel for a long time to come.