Climate balance of the building boom: multi-storey car parks help the climate

Status: 11/11/2021 8:11 a.m.

Real estate prices are high because living space is scarce. Does that mean that more has to be built? No, say experts. Potential living space is there – they consider the current boom in new construction to be “ecological madness”.

When driving by, it is not possible to see what is hidden behind the mosaic-like facade. On the one hand, you can drive into a multi-storey car park at Magnusstrasse 31 in downtown Cologne and park your car for shopping in the city. From the other side, a modern glass entrance leads into a residential complex on the deck of the parking garage. The bungalow apartments are lined up in Mediterranean white door to door at a lofty height above the city traffic. 31 apartments were created here in a prime location. The designer apartments should not provide relaxation with the Cologne real estate prices. Nevertheless, the example shows how living space can be created without sealing new areas. But so far it is only one of a few.

Surface sealing is growing

Construction is currently going on in Germany – and the climate balance is devastating. More than 60 hectares of space disappear every day – for residential construction, infrastructure, trade and traffic. Originally, with the sustainability goals of 2002, surface sealing should be limited to 30 hectares per day by 2020. However, this goal has been postponed to 2030 with the new climate targets. With land consumption around twice as high, Germany is still a long way from achieving this goal.

The consequences of the persistently high level of surface sealing: the water cannot seep away and floods are favored. With every new household, energy consumption increases, and with the current energy mix, CO2 emissions also increase.

German households together require roughly the same amount of energy as German industry as a whole. This is mainly due to the steadily growing living space per person: Currently, one person lives on an average of 46.5 square meters. In 2000 it was 39.5 square meters. There are more single households and people are living alone longer because they get older. At the same time, however, the need for new living space is growing.

Cities like donuts

Karsten Tichelmann from TU Darmstadt determined in his “Germany Study” that there is currently a need for 1.5 to 1.7 million residential units. This is currently mainly covered by new building areas around the cities. The cities spread out into the surrounding area like donuts with thick bacon belts. The further away the new development areas are from the city, the more intensive the commuter traffic becomes.

For Tichelmann this is “ecological madness”, especially since new buildings are intensively supported with subsidies such as building child allowance and KfW programs – but the construction of existing buildings and the renovation are significantly less. From his point of view, that would be the right way to go.

There is enough potential living space

In fact, there is great potential dormant in the middle of the cities. Not only parking garages like those on Magnusstrasse in Cologne, but also supermarkets and vacant office buildings could be converted. Many of these buildings are in prime locations. “Cars in parking garages don’t need a nice view,” says Tichelmann, people in apartments do.

In some large cities in the USA, a decisive step has already been taken: there, new supermarkets and parking garages are only allowed to be built underground in urban areas, as they actually do not need any light. If, in turn, the potential of existing buildings for living space were properly exploited, 2.5 million residential units could have been built before Corona, according to the “Germany Study 2019”. With the pandemic and the trend towards home offices, even more office properties are currently becoming available. They could easily be converted into living space.

Rethinking housing needs

For many, however, new building is the path of least resistance, as Anja Bierwirth from the Wuppertal Institute also knows. For a change of use, building regulations must be taken into account, ownership relationships or even the participation of financial funds must be clarified. These are often big hurdles.

But the architect and environmental scientist also calls for “a growth change”. If you look at demographic development alone, there shouldn’t be any additional demand for living space. Above all, she sees great potential in intergenerational living. Many people lived in living spaces that were much too big for their needs. They were built for a family. The time that they only spend there as a couple or even alone is getting longer and longer.

“What is really needed is not questioned,” says Bierwirth. From her research projects she knows “that many people want to stay in their neighborhood or village, but not necessarily in their apartment”. At this point, not only municipalities are in demand, but also the federal states and the federal government. She estimates that there would be enough single-family houses if senior citizens were offered elderly people as an alternative.

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