Florastrasse 28/30 extension, Zürich

The project
The aging property at Florastrasse 28/30 has undergone a total renovation. The aim of this renovation was to increase both the living space and the outdoor space (balconies) and to create four additional residential units by adding one floor. Execution In order for a comprehensive total overhaul to be possible, the building had to be cleared out. On the courtyard side, living space and outdoor space were extended in solid construction. On the street side, bay windows were hung in front of the existing facade, extending over four stories. The bay windows were made of two elements, each of which ran through two stories in height. Walls, floors and ceilings were made of cross laminated timber panels (d = 120 mm).

The method of construction
The exterior was clad with external insulation, which was also a plaster base board. The two-layer planking with gypsum fiberboard applied on the inside performs both cladding and fire protection functions. The whole bay is connected to the outer wall with special steel parts. The extension was built in conventional timber frame construction. On the boundary of the plot there was a fire wall in solid construction (REI180 nbb). A box-girder ceiling was installed over the existing ceiling. Since the existing concrete ceiling was not fully load-bearing, the load (roof, walls, floor) could only be transferred at very specific points. Since the static height of the floor box girder elements was too low for a timber application, HEA beams integrated into the elements were used.