exhibition: gebäude.grün – vom blumenfenster zum bosco verticale

Terraced housing: stacked gardens in the Bühnenberg quarter in Oftringen. The photos of the model (unfortunately lost) show it impressively: the harmony of landscape and architecture. This is not unusual, since many architects focus on the mural rather than the floral terrace form. In Atelier 5’s 1973 design for a hillside settlement in Oftringen, both come together.

The Bernese architectural firm Atelier5, which had already achieved international fame in the 1960s with its settlement designs (e.g. Halen from 1955 or Thalmatt1 from 1967), conceived the remarkable Bühnenberg hillside settlement in the village of Oftringen in the canton of Aargau from 1973. Originally, numerous single-family houses were to be built by the Bühnenberg consortium on the south-facing slope with a gradient of 50%. For the building task on the steep slope, the architects were looking for a suitable alternative to the terraced housing estates that were extremely popular in Switzerland at the time. Critics liked to refer to these as tenement houses pushed up against the slope, since there were no public outdoor areas for interaction among the residents, the angular floor plans were monotonously designed, and the access in the direction of the slope was cumbersome. On the other hand, the advantages of this type of housing, such as the private terrace or the individual apartment access, were to be adopted for the project design.

A diagonal network of paths, modeled after traditional Ticino mountain villages, formed the primary organizing system of the project. The slope of 20% not only enabled unrestricted pedestrian movement and access for small vehicles, but also created communal spaces at the intersections in the form of meeting places, which were to provide identity and orientation within the settlement. The extensive greening of private terraces, public outdoor areas, but also of the flat roofs with extensive planting favored the quality of stay in the development that was characterized by great urban density.

Atelier5 resisted an „arbitrary“ or subjective design – according to structuralist principles, a rational and methodical approach was taken instead by introducing an orthogonal grid for the structure of 5.5 by 5.5 meters as a second organizing principle for the settlement layout. On the one hand, the strict geometric specifications for the massing resulted from the relationship between the slope and the individual floors. On the other hand, the dimensioning inside the apartments allowed flexible subdivision of rooms and free arrangement of stairs. 

Based on an economic construction method, the entire settlement was staked in such a way that the slope did not have to be cut for a foundation – a constructive concept that showed similarities to the first realized terraced residential buildings in Zug. The superimposition of the two ordering principles with the topographical conditions resulted in a great spatial variation with a multitude of different floor plans, apartment sizes and programs. The systematic orientation along the slope provoked structural breaks in the settlement pattern, allowing numerous shortcuts between the building units in the form of sneak paths through the settlement. Two centrally located inclined lifts created a mechanical connection to the neighborhood center on the plain. There, residents had access to a kindergarten, studios, restaurants, shopping facilities, and an underground parking garage.  While the planning in the initial phase envisaged the entire development of the slope, adjustments had to be made in the course of the detailed elaboration, which matured to the implementation planning, since not all of the planned building plots could be acquired due to the establishment of a protection zone by the municipality. Due to the problems with the official approval and the economic crisis because of the oil shock, the innovative slope settlement was never realized. 

Plans from Atelier5’s office archive in Bern.
Images originally published in the magazine Werk.