The goal of this gray tower in Tübingen, Germany is to use as little energy as possible. Employing the principles of Passivhaus design, the JustK house by Deutschland-based AMUNT (architekten martenson und nagel·theissen), makes use of its local climate, super tight insulation, solar passive design and prefabricated elements. During the design phase, the architects also had to contend with strict building codes, a small plot and small budget, and ensuring the home's neighbors could maintain their views of Tübingen Castle across the street.
The four bedroom, 1,485 sq ft home was designed for two parents and their four children. Built on a compact lot, the home has a small footprint and is built up to taper as it reaches the fourth floor. Being considerate of their neighbors, the hip-like roof angles in to ensure views from the nearby homes were maintained.
A separate entrance provides accesses to the top two floors, which could eventually be converted into another apartment for the parents to rent out. Flexibility is found throughout the house to maximize space, which includes built-in furniture, storage and dual-purpose spaces.
Built completely out of local wood, because it was less expensive allowing the family to build within their budget, the JustK house is also prefabricated. The home consists of 136 prefabricated wooden elements built in a factory, delivered and then assembled on site. To maintain the simple wooden interior finish, all of the surfaces were sanded down and soaped in order to preserve the light character of the wood.
A tight envelope and high performance insulation ensure that no energy is lost through the cracks. The floors are staggered and during the winter cool air remains low in the entrance area and gets warmer as you head up to the top sitting room where it stays the warmest. South facing windows collect the sun’s heat and daylighting reduces lighting loads. The courtyard serves as a cold air sluice between the exterior and the interior, while part of the floor slab has been elevated so that an infiltration ditch together with a 75m ground-air heat exchanger could be installed. AMUNT started the JustK project in 2007 and completed the home in 2010.
Images ©Brigida González