Haus H27D may not seem like much from the outside, but this highly engineered building was deftly crafted to match the look and feel of the historic city centre of Constance while minimizing energy use. The five-story apartment building features walls that are 50cm (~20 in) thick made from a lightweight concrete that provides both support and thermal insulation. Designed by Kraus Schoenberg Architects, the entire building can be recycled to achieve zero waste and features solar passive and energy efficient design. The project also just received a RIBA 2012 EU Award.
Located in the historic district of Constance in Southern Germany, H27D features four private apartments and a ground floor retail shop. Kraus Schoenberg Architects‘s goal was to make the building blend into with the surrounding structures, but with radically improved sustainability. Like many urban buildings in Germany, this one features an interior courtyard for the residents to enjoy access to more daylight. The 30 meter long building shares a party wall on both sides and has a 10 meter street facade, which matches the punctuated exteriors of the neighboring medieval buildings and their directional change.
The building is constructed entirely out of lightweight fair-faced concrete that serves as both structural support and thermal insulation. The concrete even extends inside to create a fluid transition between the interior and exterior. Built 50cm thick, the walls reflect medieval techniques of building solid walls which perform as a weather membrane and thermal mass storage, but make use of modern methods and advanced materials. These lightweight concrete walls can be demolished easily and the material is completely recyclable and achieves zero waste requirements. In addition, H27D makes use of solar thermal energy system for domestic hot water, a high efficiency gas boiler for heating with under-floor heating, and grey water collection for WC’s and gardens. The thermal mass of the exterior reduces energy use and the covered south facing arcade in the courtyard and the balconies work to minimise solar gain in summer.
Images ©Ioana Marinescu