Rules must be followed until acceptance

A craftsman must work according to generally accepted technical standards. If these standards change before acceptance, the work must be adjusted accordingly.

This article is part of the special topic "Acceptance: The linchpin for tradesmen's rights".

Who bears the risk of changes to recognized engineering standards? The contractor! According to the German Construction Contract Procedures (VOB/B), they are generally responsible for ensuring compliance with these standards until acceptance of the work. This also applies if the standards change between the conclusion of the contract and acceptance, according to a recent landmark ruling by the Federal Court of Justice.

The case

The project involved the construction of three mono-pitched roof halls with steel frames. According to the building specifications, the halls were designed to withstand a snow load of 80 kg/m². This complied with DIN 1055-5 (1975) and the building permit issued in 2006. DIN 1055-5 was amended in 2005, now specifying a snow load of 139 kg/m². This amendment applied to construction projects completed after January 1, 2007. The contractor erected the halls by August 2007. When a photovoltaic system was to be installed on the roof , the company contracted for this task raised concerns about the load-bearing capacity. The client subsequently requested that the construction company reinforce the roof structure – without success. She therefore refused formal acceptance , arguing that the halls were defective because they could not withstand the snow load of 139 kg/m² specified in DIN 1055-5 (2005).

The judgment

The Federal Court of Justice referred the case back to the Court of Appeal for precise clarification of the contract's content, but provided some general guidance: 

According to VOB/B (German Construction Contract Procedures, Part B), the contractor is generally obligated to comply with the generally accepted rules of technology at the time of acceptance . This also applies if the generally accepted rules of technology change between the conclusion of the contract and acceptance. In such a case, the contractor must inform the client about the change and its consequences for the construction work – unless these are already known to the client or are evident from the circumstances.

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Customer has two options to choose from

The client then has two options: Either they can insist on compliance with the new technical standards . This may necessitate a more complex construction process than originally agreed upon in the contract. In return, the contractor may demand an adjustment to the remuneration according to VOB/B (German Construction Contract Procedures, Part B) if this results in the need for additional, unplanned work.

However, the client can also choose to waive compliance with the new technical regulations and thus avoid any potential increase in the cost of the construction project. (Whether this occurred in the present case remains to be determined by the appeals court.)

"In practice, this has been the case for a long time," explains Helge-Lorenz Ubbelohde, Vice President of the Federal Association of Publicly Appointed and Sworn Experts. "What's new now is that a landmark ruling by the highest court confirms this existing practice."

Federal Court of Justice, judgment of 14 November 2017, case no. VII ZR 65/14 (the case was referred back to the Court of Appeal for retrial).

Background: Recognized rules of technology are building engineering rules that have been scientifically proven to be theoretically correct and have subsequently been successfully applied in practice by building experts . Some of these rules are incorporated into a DIN standard , while others are adopted into further sets of regulations. Generally recognized rules of technology include all regulations and provisions that have proven correct in theory and effective in practice. If a project does not comply with these rules, the work is usually considered defective.