Transformation Dialogue „Converting buildings faster“
According to the German Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR), an annual need for 320,000 new housing units is projected until 2030. In contrast, census data shows there are nearly 2 million unused residential spaces, about 700,000 of which could be ready for occupancy within three months. In Germany’s seven largest cities, 7.6 million square meters of office space are currently vacant — 1.75 million square meters in Berlin alone. If repurposed into housing, this could theoretically create around 30,000 apartments.
Germany is, in fact, already built – just not where demand is currently concentrated and not always with the type of spaces that are currently needed.
As part of the “Converting buildings faster” Transformation Dialogue, two main questions were in focus: how can vacant housing be brought to the people and how can office space vacancies be quickly and easily converted into housing? To explore these questions, the Federal Bauakademie Foundation invited four experts who are already implementing initial solutions.
You can find a video recording of the event on our YouTube channel.
DEVELOPING EXISTING BUILDINGS IN RURAL AREAS
Frank Bachmann, Head of the Department for Construction and Urban Development in the town of Pößneck, presented the “Pößneck Method.” The town, with a population of 12,000, acts as a project developer itself. It purchases vacant (residential) buildings in the town center, refurbishes them to the shell construction stage and renovates the facades, then sells them to new investors. These investors then complete the interior development and either use the space themselves or rent it out at socially acceptable rates. The town makes use of urban development funding programs for this initiative. So far, 20 properties have been refurbished and sold to new residents.
Anne Kruse, project developer at Netzwerk Zukunftsorte e.V. in Brandenburg, introduced the network´s work. Its core mission is to give rural areas a voice and to highlight the potential for new forms of communal living within existing barns and farms. The project´s focus goes beyond housing alone to include new socio-ecological, cultural, and economic perspectives and infrastructures in rural areas. In addition to this spatial policy work, the network is developing a “vacancy-matching” platform as well as a knowledge-exchange and advisory program. These aim to connect municipalities (as well as ground lease providers) with interested parties, supporting and guiding them through the development process.
CONVERTING BUILDINGS IN LARGE CITIES
Caroline Nachtigall-Marten, an architect at Duplex Architekten in Hamburg and project manager of the “Gröninger Hof” housing cooperative project, presented her experiences with converting a vacant parking garage. This cooperative project, developed on the basis of a heritable building right (Erbbaurecht), was made possible by the Land Use Mobilization Act (Baulandmobilisierungsgesetz) in Hamburg, which allows for a new development plan (B-Plan) to be issued when repurposing an existing structure. However, during the structural analysis, it was found that the concrete structure could only be partially preserved, meaning that - from a building code perspective - the project was reclassified from a conversion to a new build. The subsequent new planning regulations and conditions were addressed through extensive collaboration and problem-solving with all involved parties, making socially acceptable rents still possible on the site. She also proposed that a dialogue and knowledge platform between public authorities and architects would be very helpful in order to streamline future approval processes. In addition, starting in 2026, Hamburg plans to introduce more flexibility in how building preservation status is defined.
Prof. Dr. Rudolf Hierl, architect and housing and standards advisor at BDA Bavaria, presented the BDA guideline "Office to Housing." This publication outlines the potential for repurposing vacant office buildings into housing, offering practical insights on suitable building typologies, funding opportunities, tax incentives, as well as technical and legal frameworks. A key highlight: the guide was developed in collaboration with the Munich city administration, recognizing that municipal authorities are crucial players in approving the redevelopment of existing buildings. The conclusion: Nothing is impossible. However, a major ongoing challenge remains the capital market. While tax relief for redevelopment could serve as an incentive, the devaluation of fund ratings for large office properties when converted to housing does not solve the issue. What’s needed is a broader shift in societal thinking.
All projects demonstrate that the ecological transformation of the construction and real estate sectors is, above all, also a socioeconomic transformation of project development and return expectations. The true gain lies in climate and resource protection, social cohesion, and an architecture that fosters cultural identity.
