Frankfurt: Existing Buildings First – But Not Existing Buildings Alone
Frankfurt is growing — housing is not keeping pace. With a vacancy rate of 0.2 percent (IHK Frankfurt am Main, Housing Market Report 2024|2025), the market ranks among the tightest in Germany — a figure that leaves practically no room to manoeuvre. At the same time, building permits in Frankfurt fell by around 40 percent between 2021 and 2024, and the Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR) puts annual new-build demand at 4,000 housing units (BBSR, April 2025) — a figure the market is currently falling far short of. The pressure on the city remains high, and it will not ease on its own.
The debate about how Frankfurt should respond is often framed as an either-or: more new construction on open land, or stronger activation of the existing building stock. In our view, this opposition falls short — and leads to worse decisions in both directions.
Frankfurt’s existing building stock holds considerable potential that remains untapped. Adding storeys to rooftops, converting vacant office space, or densifying established neighbourhoods can create additional housing without sealing new land. Infrastructure, connectivity and social structures are already in place — a substantial advantage over any greenfield site. Then there’s the climate argument: continuing to use existing building fabric significantly reduces CO₂ emissions compared with demolition and complete rebuilding, because the embodied energy of the existing structure is preserved. Existing buildings are therefore not a constraint — they are a strategic resource that needs to be used more consistently than it has been.
At the same time, the existing stock alone will not cover demand. Frankfurt also needs new neighbourhoods — energy-efficient for the future, socially mixed, clearly integrated into the urban fabric. New construction makes it possible to rethink housing typologies, create open space, and plan mobility concepts from the outset, rather than retrofitting them into structures that have already grown. The decisive question is therefore not whether to build new, but how: at what density, to what energy standard, with what social mix, and in what relationship to the surrounding urban fabric.
As alma:s Architekten, we take a clear position: every design process begins with the question of what potential lies within the existing building. Only once these possibilities are exhausted, or make no sense from an urban-planning perspective, does new construction become the next step. This is not an ideological commitment to existing buildings at any cost — it is a methodical approach that follows from our conviction that resources which already exist should be used first. Our aim is to create housing that is functional, economical and compatible with the city around it. The focus is not maximum exploitation, but urban structures that work in the long term.
Housing is not an abstract figure. It is living space — for real people, in real neighbourhoods, with real neighbours. Frankfurt’s future therefore lies not in an ideological opposition between existing buildings and new construction, but in a quality-driven combination of both strategies. What’s missing is not the insight — it’s the political and economic will to implement it consistently.
Sources: IHK Frankfurt am Main, Housing Market Report 2024|2025 · BBSR, Housing Demand Study, April 2025 · Bauplan D 2030, March 2025