The Stuttgart architect Alexander Brenner has made a name for himself by designing residential buildings and villas for a demanding clientele. Now he has built his own house and used this opportunity for a few experiments. Behind 75-centimetre thick walls, there are surprisingly light, wide rooms. Various surfaces treated with KEIM products characterise the interior.
"Brenner Research House" is what Alexander Brenner calls the residential house he built as his own builder in Stuttgart. The term "Research" formulates the claim to test one or the other innovation with this building.
Already the facade is unusual. In order to be able to dispense with insulating materials, which are often produced on the basis of crude oil, the shell consists of 50-centimetre thick cellular concrete with insulating air inclusions, which is hidden behind an outer shell of 25-centimetre fair-faced concrete. If the house is ever demolished, there is no hazardous waste, but pure mineral material that can be easily recycled. The fair-faced concrete presents itself refined by hand, as a stonemason has roughened up all surfaces over several weeks, so that the regional aggregate limestone is revealed. This gives the building a warm, beige-coloured appearance. Rough as a rock, the facades seem to grow directly from the steep terrain. They appear almost fortress-like closed to the neighbouring houses, while they open towards the valley, in a subtle composition of glass and wall surfaces.
Living on a mountain
Visitors first stand in front of a retaining wall that demarcates the hillside property from the road. The garage door is inconspicuously integrated into the cladding of metal panels. Next to it, a heavy swing gate made of black steel lets you in. One finds oneself in a roofed front yard, in which a round cut-out in the ceiling provides light. In order to give the incident zenith light a warm character, the round reveal of the glazed opening has a gold-coloured coating. KEIM Design-Lasur, a mineral stain, was applied by hand using a cloth. Thanks to the transparent binding agent water glass, the light rays hit the gold pigments unhindered and a particularly intensive colour impression is created. That would not be possible when using a common dispersion paint, because their binding agent is milky.
From the vestibule the view falls into the garage, whose walls are also treated with KEIM Design-Lasur, but this time in copper. The metallic tone goes well with the bodies of the cars parked there, while at the same time emphasising the texture of the render substrate and thus creating a surface of handcrafted liveliness instead of an industrial-sterile character.
A sculpturally shaped staircase made of fair-faced concrete leads from the hall with the entrance area to the first full floor. This open studio space is used by Alexander Brenner for painting and working on his sculptures, but also as a versatile space for small events, house concerts, readings, vernissages etc. A terrace with a beautiful view of the valley is located in front of the studio. The adjoining kitchen, but also the guest bathroom surprise with walls that are completely dipped in gold by means of the KEIM Design-Lasur, as well as many other adjoining rooms and the wine cellar.
Like the other walls treated with KEIM Design-Lasur in glaze painting technique, the metallic pigments develop a fascinating glow and play of colours in interaction with the different surfaces to which they have been applied. The private rooms begin one floor higher. While the bedroom faces the view, the bathroom is located on the hillside - from here, an elliptical entrance leads to a small, cave-like caldarium with bathtub.
Individually designed surfaces
The floor above offers space to cook, eat, linger or read in a window niche which is embedded in the thick outer wall next to the fireplace. For the walls, Alexander Brenner decided on a lime plaster from KEIM, partially tinted in various shades. The nuances are mixed especially to his ideas with KEIM Dekorfarben (Decor Paint colour powders) using rather dark, earthy pigments. These were then mixed with the white KEIM Athenit-Fino lime filler to create soft, pastel tones. Freshly smoothed by hand, the plaster presents itself with a slightly cloudy, vibrant surface. It was important to the architect that the human action, meaning the craftsmanship, is visible and not the human hand imitating a machine. Particularly in combination with the large glass surfaces, the walls with their individual colour changes appear soft and lively. Added to this are the ecological and building biological advantages of lime plaster. The use of durable and natural materials is an essential part of the concept at Alexander Brenner and especially in this house. After all, Brenner believes that the most sustainable thing is to use good materials of good quality and then use them for a very long time. Superficialities and short-living designs are not his thing.
Precise preliminary and detailed planning ensures that the effect of the carefully manufactured wall surfaces is not impaired by sockets, light switches or other disturbing elements - these are rather concealed in the built-in furniture.
The top floor finally serves as living space. It provides the best view and thus has a generous roof terrace on the valley side, which takes up the entire width of the house. Floor-to-ceiling glazing with minimised frames allows the inside and outside to merge seamlessly and is supported by the floor coverings: The oak parquet flooring in the living room with its natural grey tone corresponds to the natural stone on the roof terrace.
For ecological reasons, the floating screed under the parquet flooring is not as usual placed on a styrofoam footstep sound insulation, but on a soft fibreboard made of wood - a construction that the architect wanted to test in his own house first before recommending it to builders. It is a myriad of special details like this that make the building a walk-in, three-dimensional experiment. It ties in with the famous Case Study Houses where American architects tried out new possibilities in the construction of single-family homes in the years around 1950.
Text: KEIMFARBEN GmbH