The municipal energy supplier of the City St. Gallen in Switzerland built the first technical building to realize the energy concept 2050 of the City St. Gallen, the so called Control Center Waldau. The building, which is unusual in many respects, is essentially divided into a basement in cast-in-situ concrete and an attached concrete construction hall. The structure of the hall, designed as a system construction, is based on a square support grid with a side length of 6 m, which can be used with uniform recognizable appearance on different layers and for different uses of the works. In the transverse direction, 2-hinged prestressed frames made of prefabricated concrete elements form the primary structure, which along with the facades is supplemented with longitudinal frames. Between the frame stems reinforced concrete infillings made of recycled aggregates form the visible facade surfaces. In the roof level, foldedplate-shaped shed roof structures made of prefabricated concrete elements allow the hall to be illuminated from the north. Another special feature of the hall is the two 6.0 m high gates with concrete door wings, which allow the exchange of large technical components.