The construction task was to raise the height of a single-family dwelling in a central location in Biberach an der Riß. The existing building from the 70s stands on a steep south-facing slope. From north to south, the plot drops by ten meters over a distance of 30m. The house extended over 3 split-level floors, which had no direct spatial connection to each other. The staircase, which ran parallel to the slope, stood as a barrier between the living spaces. Connections to the garden also remained largely unused.
The as-built analysis clearly showed that the building fabric neither structurally nor spatially justified an increase in height and thus the continuation of the existing structure.
The realized design, therefore, removes the staircase, which was perceived as a spatial barrier, opens the living spaces to each other and adds to the solid building, which was partially demolished, on the valley side a steel skeleton structure enclosed in glass in an east-south-west direction, which makes the actual quality of the site tangible and accessible: The flowing living space in the middle of the slightly overgrown garden interwoven with lush vegetation.
The converted single-family residence becomes a multi-family dwelling consisting of two vertically stagged, self-sufficient, and accessible residential units, each connecting to the existing site at ground level. The first floor, which is the same level as the street, includes an eat-in kitchen, hallway, guest toilet, bedroom, study, and bathroom.
The lower living unit extends over 3 offset split-level floors with 3 bedrooms, fireplace room, 2 bathrooms, and the new living and dining room on the valley-side garden level, to which the fireplace room on the entrance level now opens itself. The new exterior staircase leads into this open space structure and provides an unexpected view of the steel frame building, the green garden, and the Rotbach Valley.
Just as unexpectedly, the elevator begins in the uphill garage, leads overall floors, and ends on the garden level.
The new building derives its form solely from its structural components and their structural order. 14 slender steel columns (100x100mm) on a 1.95m axial grid support the two-floor slabs, which are designed as composite slabs with a 6.50m span. The floor-by-floor wind bracing in the corner bays remains visible. A filigree aluminum post-and-beam façade wraps around the steel structure and plays with the two-story structure of the residential floors, which are divided into three heights.
The textile sunshade forms a second level that protects the glass building envelope from overheating in the summer like a veil, while at the same time allowing a view of the garden. Curtains create privacy when needed.
The various components of the supporting structure, facade, sunshade, and privacy screen create a fabric-like, spatially deep, ephemeral structure that changes depending on the time of year and day, the form of use, and the mood of the light.
Aretz Dürr Architektur