The owner moves into the finished space, uses it day to day, but does not pay the final invoice in full. Three months later a water leak appears, and no one can show whether the warranty period has already started or the contractor still carries the burden of proof. This is exactly the point where acceptance under VOB/B, the German construction contract rules, or the BGB, the German Civil Code, decides who holds which cards in a dispute.
Why acceptance decides money and liability
Acceptance under section 640(1) BGB is the moment the owner recognizes the work as essentially conforming to the contract. Only once acceptance has taken place does the contractor's fee become due in full, section 641(1) BGB. At the same time the warranty period starts running, for buildings typically five years under section 634a(1) no. 2 BGB, or four years under section 13(4) no. 1 VOB/B if the parties validly agreed to apply VOB/B. Acceptance also flips the burden of proof: until then the contractor must show the work is free of defects, afterward the owner must prove a defect exists. Anyone who fails to document this moment clearly loses, in a dispute, exactly the records needed most.
Formal acceptance: process and required content
Formal acceptance is the safest way to create legal clarity. Owner and contractor agree on a joint inspection date, walk through the work together, and record the result in writing. Under section 12(1) VOB/B, the owner must carry out formal acceptance when the contractor requests it; the customary deadline is twelve working days after written notice of completion, unless another deadline was agreed. On larger projects, a partial acceptance for individual trades or construction phases is worthwhile, for example when one trade finishes well before the rest of the project. For consumer construction contracts, section 650g BGB additionally provides for a joint condition report if the consumer refuses acceptance even though the work is essentially complete. How a site walkthrough becomes a complete record is covered in Begehungsprotokoll: vom Rundgang zum vollständigen Protokoll, an article on turning a site walkthrough into a complete report.
Implied acceptance: when it occurs, and when it does not
Not every acceptance under VOB/B is formal. If neither side requests a joint date, acceptance can occur by operation of law. Under section 12(5) no. 1 VOB/B, the work is deemed accepted twelve working days after written notice of completion if the owner, by then, has neither requested acceptance nor refused it while naming defects. If the owner actually starts using the work, for example by moving in or commissioning a system, section 12(4) no. 2 VOB/B applies after only six working days. In a BGB construction contract without a VOB/B agreement, section 640(2) BGB provides a similar mechanism: if the contractor sets a reasonable deadline for acceptance and the owner does not respond, or refuses without naming at least one specific defect, the work counts as accepted. In practice this means an owner who uses a building without declaring known defects may unintentionally trigger the start of the warranty period and lose leverage over the contractor.
Declaring reservations for known defects correctly
Known defects are not automatically lost if the owner proceeds correctly. Under section 640(3) BGB, the owner's rights regarding a defect known to them at acceptance survive only if they expressly reserve those rights at acceptance. The reservation must identify the defect specifically enough that the contractor understands what is meant; a blanket phrase such as “subject to all rights” is usually not enough in practice. Without a reservation, typically only the claim for supplementary performance, meaning a cure of the defect, survives, while the right to a price reduction or damages for that specific defect can be lost. That is why every defect found during the walkthrough belongs in the record individually, with location and description. How defects get tracked continuously up to acceptance is covered in Mängelmanagement auf der Baustelle: bis zur Abnahme, an article on defect management until acceptance.
What belongs in the acceptance report
An acceptance report only holds up if it is complete. At minimum it should include:
- the project name and the underlying contract
- the date, time, and participants of the inspection
- an explicit statement on whether the work is essentially conforming to the contract
- every identified defect listed individually with location, description, and ideally a photo
- a statement on whether and which defects remain subject to a reservation
- a deadline for remedying the listed defects
- notes on remaining work or open items
- signatures of both parties with the date
If any of this is missing, it later becomes nearly impossible to establish whether a defect was already visible at the inspection or arose afterward. A template for a complete acceptance report helps make sure none of these points gets skipped.
Checklist
- Announce the acceptance date in writing early and track the deadline under section 12 VOB/B or section 640 BGB
- Carry out your own walkthrough before the joint date and document defects in advance
- At acceptance, name every identified defect individually rather than noting them as a group
- State reservations for known defects explicitly and specifically
- Agree on separate partial acceptances for completed trades
- Avoid using the building before declaring defects if you want to preserve claims
- Have the report signed by both parties and share a copy with everyone involved
- Set concrete dates for defect remedies, not just “soon”
- Note the start of the limitation period under section 634a BGB or section 13(4) VOB/B in the project calendar
Frequently asked questions
What happens if the owner refuses acceptance without a reason?
If the owner refuses acceptance without naming a specific defect, acceptance can occur by operation of law under section 640(2) BGB or section 12(5) no. 1 VOB/B. The contractor should give written notice of completion and document the deadline set, so the implied acceptance can later be invoked.
Does the owner need to bring an expert to the acceptance inspection?
There is no legal requirement to do so. For complex trades, or where disagreements already exist, an independent expert opinion before reservation and defect notice deadlines start running can still be valuable.
Can acceptance happen silently, without any statement?
Yes. If the owner takes the work without objection and uses it as their own, that conduct can amount to implied acceptance. What matters is whether the owner's behavior clearly shows they accept the work as essentially conforming to the contract.
What is the deadline for defect claims after acceptance?
For buildings, the limitation period for defect claims under section 634a(1) no. 2 BGB is five years from acceptance. Where the parties validly agreed to VOB/B, section 13(4) no. 1 VOB/B often sets a four year period unless otherwise agreed.
How does acceptance differ from a mere transfer of possession?
Transfer of possession is the physical transfer, such as handing over keys. Acceptance is the legal declaration that the work is recognized as essentially conforming to the contract. The two can happen at the same time, but they do not have to.
Conclusion
Acceptance under VOB/B and BGB decides when the contractor's fee becomes due, who must prove a defect, and when the warranty period starts. Owners and contractors who use formal acceptance, state reservations specifically, and keep a complete report avoid the most expensive disputes at the end of a project. Structify, software for digital construction documentation, connects site walkthroughs, defect management, and acceptance reports within one project. If you would like to see how that looks on your project, book a short online demo.