Kernrechtsfrage
Whether the builder’s reference to SIA Norm 118 in the works contract constituted an external notice of the architect’s authority to order extra work and changes.
Extrahierter Entscheid
Yes. For a builder experienced in construction, referring to SIA Norm 118 informed the contractor that the architect was generally empowered with the authorities described in that norm, including those in Article 33.
Extrahierte Begründung
The court held that Art. 33(3) OR applies where the principal externally communicates a power of representation. The written contract expressly incorporated SIA Norm 118, which contains specific rules on the site management’s authority. Because the builder was industry-savvy, the reference was not unusual and operated as a valid external notice of authority. The contractor was in good faith and had no reason to assume a narrower internal mandate.