The workers’ house on Gustavstraße was built in 1911 and comprised three storeys of flats as well as several attic rooms. Having been used as a twelve-room ‘city villa’ during the last century, we were given the opportunity to design its third phase of life. The flexible, compartmentalised floor plan has been retained and complemented by new features and functions. A second staircase, attached to the exterior of the house, provides direct access to the upper half of the building; open-plan bathrooms allow for a variety of usage scenarios; a crane-like extension juts out into the garden, opening up the house towards the treetops. The house can thus be used as two units with a communal area in between; as three separate units; or, with minor adjustments and additions, as up to four units.

The radical structural and design logic of the house places the utmost importance on the rear garden. Whilst only a minimal amount of land is re-developed, the extension creates a multitude of new functional benefits. Each element has its own design and structural logic, in line with its specific characteristics, constraints and requirements. A monolithic fire wall made of thermally insulating bricks provides structural rigidity and separates the flats from the neighbouring plot. The cantilevered structure connects to the existing building and transfers its horizontal forces into its foundations. The horizontal beams are specifically configured on each floor: a concrete foundation in the garden, a double timber beam penetrating the thermal envelope on the ground floor, simple metal beams on the first floor, and a structurally active elevation beneath the roof: staircases, balconies, kitchens and baths are treated as objects, freely positioned on or within the house. The lightweight façade lies autonomously over the internal structures.