Conversion and new build to densify a courtyard
Basel, Switzerland
Project: 2020-2024
Completion: September 2024
Colmarerstrasse.
Overview
Client
Private
Architecture
Rahbaran Hürzeler Architekt:innen, Basel, Switzerland
Team ZPF
Milad Amini, Taylan Beyaşahin, Rosanna Dottolo, Heike Egli-Erhart, Ana Maria Eigenmann, Oliver Fricke, Kata Aletta Orbán, Vanessa Petitto, Sali Sadikaj
Publications (selection)
The property at Colmarerstrasse 14 was originally a typical perimeter block development of the district, featuring a deep rear courtyard with several ancillary buildings. The structures on the densely built plot were of varying ages and in poor condition. They were replaced by an ensemble combining different housing types, studios and small-scale commercial units. The concept achieves densification without sacrificing the idyllic character of this Basel courtyard.
The front building was demolished down to the basement enclosure walls and the firewalls made of natural stone. In its place, a six-storey residential building with commercial spaces was erected. The filigree concrete skeleton structure is complemented by timber construction elements and wrapped in a thin metal weather skin. Facing the courtyard, the façade is clad in timber boarding – a feature repeated on the other courtyard buildings. By reducing the load-bearing system to a few slender columns and a stabilising stair core, material use was minimised while providing flexibility in the floor plan for future adaptations.
Within the courtyard, three timber buildings were constructed. A former rear building with a wine cellar was replaced by three terraced houses in prefabricated timber construction, each with roof terraces. The underground natural stone exterior walls at the rear were preserved. The inner shell adjoining the stone masonry is made of a minimal amount of concrete to ensure seismic stability. The natural cellar walls thus stand in contrast to the newly built studio space in the basement, accentuated by light wells that draw daylight inside. Opposite the townhouses, a single-storey timber pavilion was built, suitable for both living and working.
At the far end of the site, the former stable building was converted into a two-storey open studio. The ground floor façade was rebuilt in masonry, while the ceiling and roof were executed in timber construction. The original beam structure was retained as far as possible, reinforced where necessary, and complemented with contrasting new elements. A red steel spiral staircase now connects the three levels of the newly created live-work atelier.