There are approximately 13.5 million single-family homes in Germany, occupied on average by fewer than two persons. At the same time, there is a shortage of around 1.4 million housing units in the country. Many people remain in their large homes despite changing life circumstances. Converting parts of these houses into two separate residential units would make a significant contribution to resolving the housing shortage — and would do so without the need for expensive, resource-intensive new construction.
The MAR conversion project explores this underestimated potential. The century-old single-family house — which had undergone multiple alterations and extensions over time — had become too large for its two residents after their children moved out. The conversion creates two residential units of different sizes within the existing volume. These provide space and sufficient room for two generations and allow for future rotation based on the residents‘ life stages and household sizes.
The new timber façade unifies the extensions added over various decades and makes the building’s division visible from the outside. Damaged timber walls and the roof structure were replaced, while the existing solid structure was largely preserved. The renovation focused on a robust, resource-efficient design, utilizing renewable building materials — such as wood and clay — alongside recycled materials.
The house is understood as the center of a usage cycle and the structure as part of a material cycle. Thus, the conversion follows the principles of circular construction: components are designed with detachable connections to allow for their removal without damage during future changes, while robust assemblies ensure the structure’s longevity. The new exterior walls are designed as material-efficient timber-frame structures. The same construction method is also used to upgrade the thermal performance of the existing masonry walls.
The bright, warm interiors of the new residential unit are defined by three materials: local fir and ash wood, white clay plaster and white and bright blue tiles manufactured entirely from recycled construction waste by a German start-up. These flamboyant tiles often spark lively conversations about the renovation’s circular approach.
Through spatial transformation and the use of renewable, eco-friendly, and recycled building materials, the existing structure is repurposed — demonstrating how a smaller footprint can yield a higher quality of living.
