At first glance, the unconventional shape of the Just K house might lead us to assume that we have stumbled upon an architect’s folly in Tübingen, Germany. A closer scrutiny of this innovative, zero-energy house reveals a concerted and thoughtful method to the madness.
Designed by architects Björn Martenson, Sonja Nagel, and Jan Theissen of German-based design practice AMUNT, the house was awarded the prestigious AR 2011 House award (not a surprise in this age of conscientious building). Conceived with a passive energy system, sustainable building materials, and a limited budget, the Just K house skillfully accommodates a family of six in a mere 1,500 square feet; offering a viable, efficient, and appealing vision of future living.
Above: The chamfered form of the house has a dual function of preserving views to Hohentübingen Castle while repelling the elements of wet and stormy weather.
Above: "Based on considerations of sustainability, the physics' requirements of passive houses, and the opportunities to reduce the construction phase by using prefabricated materials; we decided to build the house with solid wood construction," says architect Jan Theissen. "Also as a renewable resource, wood has a very favorable energy balance."
Above: The kitchen is an integral part of the main living area, optimizing the use of the available space in terms of functionality and flexibility.
Above: Just K is made of up of 136 prefabricated pieces which arrived on site with pre-cut notches, drill holes, and grooves so that the house could be put together like a three-dimensional puzzle. While the staircase accommodates a utility room, it is also used for seating.
Above: All the wooden surfaces have been sanded down and soaped to give a uniform light feel throughout the house. "We wanted to achieve the maximum in spatial qualities with the minimum use of materials," says architect Sonja Nagel.
Above: "In the main living space the different functional areas: sunken courtyard, entrance, cloakroom, kitchen, eating area, balcony, living area, window seating area, mini-office, and staircase – overlap imaginatively, creating a living environment that gives the inhabitants a feeling of spaciousness, providing different atmospheres and potential uses of the space despite its small size," says Nagel.
Above: Just K sits slightly elevated above the ground in order to accommodate a ground-air heat exchanger beneath it, which enables the house to benefit from the stack effect, a passive energy system. In the winter, solar panels on the south face insulate the envelope of the house, the hot air then circulates and rises up through the house. In the summer, the system draws the cooler night air in from from outside and funnels it down, ensuring comfortable daytime temperatures.
Above: In order to maximize solar gain, windows are placed on the south side of the house with operable shading panels working as traditional shutters. The sliding door between the kitchen and balcony allow for the space to expand another 130 square feet.