AR House 2011 Winner: this dwelling is a radical and energy-conscious reinterpretation of the suburban villa
Set in a suburb of Tübingen, on a south-facing hillside with views over the city and its castle, this new house provides living space for a couple and their four children. The suburb dates from the 1920s, and its leafy environs are populated by large, sedate villas. Designed by Björn Martenson, Sonja Nagel and Jan Theissen, Just K is a conspicuous modern addition to this placid and verdant setting.
Among nearly 200 entries for this year’s AR House Award, Just K’s distinctive warped and canted tower immediately caught the jury’s eye. However, beyond the initial impact of form, closer study revealed a highly thoughtful approach to issues of energy use and the evolving family unit. It was one of the very few submissions to acknowledge that the modern family is an inherently mutable entity, and how this might impact on the way in which space is used and organised.
Like its neighbours, the house is an object building in the landscape, but it gives the archetypal villa a new and incisive twist. The demands of the programme, the parameters of the site and the need to preserve views to Tübingen’s castle conspired to generate a chunky, chamfered form. The architects liken it to a traditional sou’wester fisherman’s hat, and it repels the elements in an equally effective fashion. A grey roof membrane covers the upper part of the house, forming crisply defined ridges at its edges, which help to channel and throw off water, like the brim of a hat.
The house is situated on a slightly elevated site above the ground, so that a ground-air heat exchanger could be sunk into the site as part of a strategy to maximise the principles of passive energy use. The building envelope is highly insulated with solar panels on its south face, and through the stack effect, hot air circulates up around the dwelling, warming the house in the winter and ventilating it in the summer. Inside the tower, spaces slot together with the elegant economy of a Chinese puzzle.
A set of entrance stairs leads up into the house’s social fulcrum, a large, south-facing kitchen and living room, connected to a generous balcony. A more intimate secondary living space and study are placed on an intermediate mezzanine level, with bedrooms on the first floor. Above this is an upper storey that can be used as a playroom, guest bedroom or home office, with a gallery in the attic, utilising every last corner of space. This upper part can be closed off and accessed separately from its own entrance and staircase, so if family circumstances change, the house can be simply and efficiently subdivided.
Considerations of sustainability and construction time led to the house being constructed entirely from timber. Like a giant jigsaw, the building consists of 136 prefabricated elements, with notches for carpentry, and drill holes and grooves for electrical installations. The timber surfaces - spruce walls and fir floors - have been sanded down to give the interior a delightfully refined, homogenous quality.
The jury applauded the cool yet radical intelligence displayed by the architects in this winning project. Underscored by a concern for the use of resources and energy, Just K conceives the house as both a compelling physical object and a responsive armature for modern domestic life.