Who chooses the concrete exposure class?

OLG Hamm, judgment of 14.12.2017, az. 24 U 179/16

An underground car park must be able to withstand the chloride load caused by the de-icing salt through which the cars enter. Structural engineer (structural engineer) and architect did not consider this. When choosing concrete, the structural engineer did not establish appropriate specifications for the required exposure class. The architect took over this.

According to the expert mandated by the court, it is actually up to the structural engineer to specify the required class of exposure for the concrete.

If the architect's plans are based on erroneous plans provided by the client, he must accept the contributory responsibility of his specialized planner. The structural engineer named by him is notably his agent of execution. This was the opinion of the Federal Court of Justice in the "judgment on glass facade" (BGH, judgment of 27.11.2008, ref VII ZR 206/06) and later in the judgment of 14 July 2016 (ref VII ZR 193/14).

In this case, however, the architect has an independent contractual obligation to take precautions to protect the building from damage due to chloride contamination. If he knows the situation that entails the particular requirement for the class of exhibition, namely the use as underground parking, he is responsible for his own fault. He needs to know that winter salt causes a chemical attack.

He must counter this danger as part of his planning.

In case of doubt, the architect should have consulted the structural engineer.

Since the architect has not lived up to his planning task, he is alone.


It must also be taken into account that other possibilities were available to protect the building from chemical constraints, for example an epoxy resin coating. However, the choice between different approaches belongs to the architect.

If the class of exposure is not expressly agreed, claims for defects with regard to the manufacturer and the supplier of ready-mixed concrete may also be taken into account.