Of course, the existing building was so much more than just an underground car park. This house, which was built in Grunewald in 2014, has three floors staggered from street level down to the „Hundekehle“ lake and is therefore barely visible from the street. Nevertheless, the underground car park built into the hillside with a car elevator dominated my first impression on the first visit to the site. The very sober, orthogonal facade with stainless steel railings was also more reminiscent of an office building than a residential building. Everything seemed quite strict. This is how the idea came about to capture the softness of flowing water of the lake and bring this completely different design language into the building. The staircase between the garden floor and the mezzanine, which blocked the view to the lake, was moved to the part of the building that is behind the massive load-bearing center wall. Through cutouts in this load-bearing wall, rooms on the garden level that were not originally naturally lit now open up into the light-flooded living space. The former ceiling opening of the stair now forms a double height space that connects the garden floor and the mezzanine. Parts of the former underground parking have been converted into a exercise room and a spa. The former car elevator shaft is turned inro a large skylight which now illuminates the basement with natural light. The garden façade was only minimally but essentially modified for the use of the house: A large fixed glazing panel on the garden level was replaced with a spacious sliding door. To improve ventilation of the rooms on the mezzanine, a large sliding door was replaced by two smaller elements. The contrast between the “round and the square” runs through the entire design and served as a common thread for the selection of details such as tile patterns, light fixtures and furniture details. The staircase between the garden level and the mezzanine level, which blocked the view of the lake, was moved to the part of the building behind the solid load-bearing central wall. Cut-outs in this load-bearing wall opened up rooms on the garden level, which were originally not naturally lit, to create a light-flooded living space. The former cut-out in the ceiling of the staircase became an air space connecting the garden level and the mezzanine floor. Parts of the former underground car park have been converted into a sports and spa area. The former car elevator shaft has been transformed into a large skylight that now provides natural light to the basement. The garden façade was only minimally altered, but essential for the use of the house: A large fixed glazing on the garden level was replaced with a large sliding door. A large sliding door was replaced by two smaller elements to provide more effective ventilation for the rooms on the mezzanine floor. The contrast between the “round and the angular” runs through the entire design and served as a common thread for the selection of details such as tile patterns, lights and furniture handles.