J.H. Keller AG

On Vulkanstrasse in Zurich Altstetten Fischer Architekten have undertaken a comprehensive and ambitious renovation of a building envelope for J.H. Keller AG. Before this work began former storage spaces were converted into offices and studios.
–

J.H. Keller AG has been based in the industrial district on Vulkanstrasse in Zürich Altstetten since the mid-1950s. This family business is housed in an ensemble consisting of a multi-storey building on the street with a storage and production building behind it. In 2016 developments in the car trade led the clients to convert the first floor of the hall-like rear building into studios, offices, and workshops for small businesses. Flexible cellular spaces and ancillary service rooms were made within the existing loadbearing structure and are reached by the distinctive approach ramp that helps shape the building’s character.

From 2019 onwards this conversion work was followed by a complete energy efficient retrofit of the building envelope. The aim was to reduce energy consumption and to renovate and extend the existing photovoltaic plant. From a design perspective the challenge was how to integrate these two industrial buildings in a neighbourhood that has changed radically, while at the same time preserving their character.

The most striking intervention is the roof to the hall building, which is covered with a foil roofing material laid over a new substructure. The roofing is continued down over the facade of the second floor, giving the building a very individual and specific quality. The attic floor of the multi-storey building was replaced by a new sixth storey that uses a light-weight steel and wood construction. Higher than the standard floors and almost entirely glazed, this storey is a light, transparent termination to the building volume.

On the south-facing main facade of the multi-storey building made-to-measure PV panels were integrated in the existing parapet bands. The PV modules on the gently pitched roof to the hall building were replaced by a state-of-the art system and augmented by additional panels mounted on the flat roof of the multi-storey building.