The cube almost seems to float above Stuttgart valley: High over the street, a recessed garden supports two overhanging floors. The building’s façade features large windows on the southern and western sides – the other sides are more private, with only narrow bands of windows offering targeted views outward, but barely a glimpse of the interior. The orange tone of anodized, bronzed aluminium – the material from which the window profiles, sun-protector and garage door with its perforated metal look, as well as the external doors are made – reflects on the light-coloured, partially sandblasted exposed concrete, setting warm accents. Unlike most external sun protectors, this one is a formative design element: When folded upward, the metal segments, in contrast with the regularity of the façade, function as a constructive barrier against the sun. When closed on a sunny day, the perforated metal pattern casts wonderful auras of light within the rooms.
The building is heated exclusively with an external, temperature controlled heat pump. Four boreholes were drilled at a depth of 160 meters each, in order to tap into geothermal energy. So the homeowners are not dependent on oil and gas; they only need electricity to operate the heat pump, which provides under-floor heating, storage of drinking water and the thermal activation component. A solar panel on the roof is used to heat the water in the pool and to maintain its temperature.
The inside is just as simple as the outside: Here, too, only a few materials and colours have been used. The ceilings and some walls are done in exposed concrete; the remaining walls are extremely smooth, and painted white. The central, functional core of the building is distinguished by its deep brown colour, which matches the brushed oak of the floor-to-ceiling kitchen furnishings. The floors, too, are made of warm-toned materials: In the living area, the floors are of porous, Oberdorla limestone, while upstairs the dark brown of the smoked oak flooring reflects against the off-white walls. These walls perfectly set off the simple, elegant furniture classics; the built-in furniture and kitchen were created by a carpenter according to the builders’ design. Small, ceiling “downlights” set accents in the space; indirect lighting and a few strategically placed lamps create a dramatic effect. Whereas indoor living takes place over three levels plus garage, the outdoors features five terraced levels on the steep slope, each one supported by retaining walls of exposed concrete. Limestone was used outside as well, to make a smooth transition between interior and exterior. The various terraces form atmospheric retreats and meeting points, for every situation and mood.