In the course of the project for the new office building, Villa Rosau was completely refurbished. The historical villa was constructed by the architect Ferdinand Stadler in 1844/45 for residential use. As most of its original substance was lost during previous remodelling, conservation efforts were concentrated on the building envelope. It was thoroughly renovated and in places restored to original condition. Furthermore, the building received a new structural foundation, while the former spatial arrangement was rebuilt from scratch. The villa houses the Club Baur au Lac and comprises a semi-public bar and restaurant on the ground floor with meeting rooms, a fireplace lounge and offices on the upper floors.