Densification changes cities
Building densification is progressing in the five largest Swiss urban centres. New flats are being built on brownfield sites and through replacement construction, often at the expense of lower-income households. A recent ETH study shows how the housing market in Basel, Bern, Geneva, Lausanne and Zurich has changed in recent years and what social tensions have arisen as a result.
The study “Construction activity and displacement”, carried out by ETH Zurich on behalf of the Federal Office for Housing, shows that over the last two decades, settlement development in Switzerland has clearly been inward-looking. New housing is being built in urban areas, primarily through replacement construction and the conversion of industrial and commercial zones, rather than on greenfield sites. In cities such as Basel, a quarter of new flats were built on former industrial sites.
More flats despite fewer new builds
Although the number of newly built residential buildings is falling slightly, the net number of flats continues to increase. This is due to the efficiency of densification. In Basel, Geneva and Lausanne, up to twice as many new units are being built per demolished flat than in Bern or Zurich. Densification is thus becoming the central lever for creating living space in densely populated areas.
Who is being displaced?
The downside of densification can be seen in the social composition of the neighbourhoods affected. In Zurich in particular, long-term tenants often lose their homes due to demolition or total refurbishment. Those who have to move out often have a significantly lower income, up to 40 per cent less than the average. In contrast, households with above-average incomes move into new builds.
Migration and income as a risk factor
The study also reveals structural disadvantages. Asylum seekers, refugees and people of African descent are disproportionately affected by displacement. This means that structural densification particularly affects those who are most dependent on affordable housing and who often can no longer find it in the same municipality. Nevertheless, a considerable proportion of those affected, up to 64 per cent, manage to stay within their municipality.
Cities in transition – socially balanced?
From a spatial planning perspective, densification is sensible and necessary. However, it not only changes the cityscape, but also the social structure of neighbourhoods. The challenge in the coming years will be to shape change in such a way that it does not lead to social division, but to mixed, resilient cities with living space for everyone.