Address: Justinus-Kerner-Strasse, Tübingen, Germany
Architects: AMUNT - architekten Martenson und Nagel Theissen, Aachen/ Stuttgart  // Björn Martenson, Sonja Nagel, Jan Theissen
Structural planning: Ingenieurbüro von Fragstein, Dipl.-Ing. (Fh) Wenzel von Fragstein
Energy planning: Dipl.-Ing. Jörg Lammers
Site: 365 m²
Floor space: 138 m² (81m² + 57 m²)
Gross floor area: 278 m²
Cubic content: 583 m³
Energy needs: 14,4 kWh/(m²a)
Building costs: € 330.000,-
Design period: November 2007 to December 2008
Construction period: April 2009 to June 2010 (with discontinuities)
Photographer: Brigida González

Zero energy houses have a soft place in our design quests and are a definite favorite of ours as a source to save all that is called Nature.  As time progresses the esthetics for such residences is constantly challenged by architects in order to create a maximum use for an eco friendly structure while encompassing the clients needs for all that is design.  One very successful marriage of these two factors has been achieved by the architectural office known as AMUNT (architekten martenson und nagel·theissen).  Based in Aachen and Stuttgart, architects Björn Martenson, Sonja Nagel and Jan Theissen commenced the JustK project in 2007 and completed it in 2010 with great success.  A living space for 2 adults and 4 children it encompasses all that can be expected from two worlds.

The prime focus for this 138sqm construction was none other than Zero energy, taking advantage of all of the natural surroundings and weather conditions.  With primal views of the Tübingen Castel the swing of the hipped, multiply kinked roof was designed taking into consideration the neighbors same rights to these exceptional viewpoints.  The south facing façade is glazed for maximum solar gain with open-work shading panels acting as traditional shutters.  The entrance is situated on the same level as the courtyard serving as cold air sluice between exterior and 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. There is also a look to the future with this structure with the presence of splittability. A separate apartment can be created with an independent direct access from the outdoors by separating the main living space with a wooden partition wall on the top floor. As a whole the exterior has been designed so that everything possible can be put to use. There are walls & steps to sit on, an outside kitchen/barbeque area for summer cooking and planted apple trees for pie baking and personal delight.

The layout of the house consists of three staggered levels, creating various heights which zone the ground floor and automatically create different climate zones in winter.  Designed with wood being the main material used consistently throughout the structure as a renewable raw material it was chosen not least for its favorable energy balance. In order to keep costs down the wooden surfaces in the common rooms have been designed in ‘refined shell construction’.  All the wooden surfaces have been sanded down bucked and soaped in order to preserve the light character of the wood.

The ground floor living room which is situated above a lower courtyard changes orientation. Fully glazed it opens up to the west to catch the evening sun.  A magical site to the eye which becomes even dreamier having the window sill designed as a bench to sit and admire of all that lies in front of you. This flexibility of space is present throughout this residence. Examples of this is the large glass sliding door connecting the Kitchen-Living room to the balcony extending the space by 12sqm and also the staircase accommodating a utility room while also serving as a stage/seating area. Everything has been designed to allow for a multi purpose use.

As one ascends the staircase it widens and it introduces you to the upper level consisting of large frameless glazing, flooding the space with natural daylight. Everything is built in, concealed and no excess of any kind is allowed for. The top floor living-room hall provides room for retreat and serves as what we would call a very controlled reading and television area. Through the architecture there is no room for energy lost or any type o misbehavior everything is designed to what is absolutely necessary needed and designating the lifestyle accustomed to this house. On the final level to what is called the attic is a space with the potential of different uses.  A workspace, a play room or even a bedroom.  This is definitely the room to let loose in and blow out some of that much saved energy.

This project has successfully incorporated the respect which is much owed to the environment together with the presence of man going about his daily chores with no restrictions or inhibitions to his lifestyle.  One can say it is the long awaited unity of man, nature and design.  A dream ''threesome'' from which everyone comes out satisfied and respected.