With a cleverly positioned extension and an additional floor, a small worker’s house was transformed into an elegant townhouse featuring two spacious two-storey apartments. The walls were built of brick and a new tiled roof was added to cover the successful conversion.

Project details

Project Conversion of a townhouse in Zurich, Switzerland
Architect Imroth GmbH, Flawil
Client Margrith Roth, Zurich
Roof tiles Plano roof tiles
Clay blocks Swissmodul
Floor area 218 m2

Renovation, Swissmodul

Conversion of a townhouse in Zürich, Switzerland © Christian Senti

Conversion of a townhouse in Zürich, Switzerland © Christian Senti

Conversion of a townhouse in Zürich, Switzerland © Christian Senti

Conversion of a townhouse in Zürich, Switzerland © Christian Senti

Conversion of a townhouse in Zürich, Switzerland © Christian Senti

The surrounding

The districts on the northern outskirts of Zurich used to be rural communities, which were only urbanised as industrialisation took hold. This led to a large number of estates being built for employees of the major industrial enterprises. The worker’s house built in the Affoltern district in 1930 is typical of its time: to keep as much of the narrow plot of land free for a self-sufficient lifestyle as possible, the house was joined to the one next door at the plot boundary.

Doubling the volume

This meant that the space available no longer met modern requirements, and since there was permission for the house to be extended and have an extra floor added, it was converted and expanded in 2005. The aim was to create two two-storey apartments with spacious layouts in the converted house. To this end, another floor was added to the building and a cube-shaped extension built on the side facing the courtyard. This meant that each of the three storeys was enlarged by 20m2, while the top floor was given a terrace on the roof of the annexe. The extension and the existing house are merged by the open-plan layout, creating the spacious rooms initially aimed for, especially as the building volume more than doubled, from 410m3 to 870m3.

Clay building materials for walls and roof

The extra storey and the wall separating the extension from the house next door were built of brick. This was clearly the best solution, as it was simple and low-cost to construct and, in the case of the extension, provide the necessary level of fire protection and noise insulation. “Using bricks made it possible to keep the building’s original material concept while enhancing it in a logical way,” says architect Martina Roth. The new roof, which is now one storey higher and thus has the some ridge height as the house next door, was covered with dark grey roof tiles. The conversion has thus transformed the former worker’s house into an elegant building with a consistent colour concept. The grey roof perfectly matches the red-dyed wooden slats on the extension and the façade of the existing building, which was given a plain white finish.

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