Adding floors instead of building new ones: In order to create additional living space in Berlin, the state-owned housing association Howoge has added a few floors to an existing prefab apartment building in the north-eastern district of Buch. Three new floors and more than 20 new apartments were created in this way in just under two years of construction on Franz-Schmidt-Strasse. Experts see a lot of potential for the German real estate market in such existing projects, both with regard to the housing shortage and sustainability. But there are some hurdles.

The topic has long since arrived in politics. Federal Building Minister Klara Geywitz and Berlin’s Governing Mayor Franziska Giffey want to get an idea of ​​the extension project for themselves on Wednesday.

Howoge currently owns around 74,500 apartments in Berlin. “If we look at our stock, especially in the east of the city, then we usually see the classic building type WBS 70, i.e. residential slab, which was built in the late years of the GDR,” says Howoge Managing Director Ulrich Schiller. “They are mostly five and six stories high. What could be better than adding stories to these buildings?”

Wood should be used more

Thousands of new apartments could be created in this way at Howoge alone, Schiller estimates – new apartments that neither sealed up undeveloped areas nor allowed the city to fray further at its edges.

Experts see other advantages: “Light construction is generally used as a rule,” says Anna Braune, head of the research and development department at the German Sustainable Building Council (DGNB). “Here, wood in particular is an important material.” And thus one that can be used to build much more sustainably than steel and concrete.

In addition, the lower floors often also benefit from the construction: in Berlin-Buch, for example, there is now an elevator that did not exist before. The lines were also renewed throughout the building and the building shell optimized, says Schiller.

A few years ago, researchers at the TU Dresden calculated in a study the potential of 1.1 to 1.5 million new apartments that could be built nationwide on residential buildings from the 50s to 90s.

Construction work disturbs residents

But especially in densely populated areas, the plan to increase is usually not met with much enthusiasm. “Of course, tenants in the existing building experience a great deal of stress as a result of the construction,” says Schiller. The construction work causes dirt and noise and in some cases the buildings are temporarily uninhabitable, for example because a new staircase is being built.

In crowded neighborhoods, residents also fear for the already scarce parking spaces and even more traffic jams with additional residents, says DGNB expert Anna Braune. There was also the concern that the new neighbors would not fit into the social fabric of the neighborhood. “These are issues that actually only work if the municipal representatives also moderate them appropriately,” says Braune.

In any case, the district authorities in Berlin often do not grant approval for potential projects because construction projects in closed neighborhoods are currently viewed critically, emphasizes Schiller. With the so-called modular design with prefabricated components, the company is trying to shorten construction times and reduce costs.