Addition of storey Gartenstrasse, Zürich

The project
The office building of Lienhardt & Partner Privatbank in Zürich AG at Gartenstrasse 14 in Zürich was getting on in years. Thanks to a new facade, the perimeter block building from the early 1920s once again meets the latest energy and aesthetic requirements. Floor-to-ceiling mullion and transom glazing made of wood/metal was installed on the first floor. On the floors above, Kohler + Ilario Architects planned large-format fixed glazing with side opening sashes made of wood and metal. In the course of the facade renovation, the building was raised by one floor. The addition of four apartments on the attic floor further enhances the property.

The construction
The facade construction is made of wood and metal elements. The extension on top of the existing solid building is made of solid wood elements. Beams made of beech veneer were used where necessary.

The challenge
The construction work was carried out while the office building was in operation. This required meticulous planning and consistent prefabrication of the construction elements. An additional complication was that the details of the geometry of the existing building were inaccurate in some cases. This requires flexible connection details. Another challenge is the cantilevered connecting structures. They were necessary because the facade supports are arranged outside the concrete slab of the solid building.