How can we build more housing in crowded cities? Bill Price, the director of the construction consultancy WSP | Parsons Brinckerhoff, has some ideas.

In many cities, soaring house prices are a reflecting of growing demand: people increasingly want to live near city centres, for work, play, and all the other attractions they provide.

But in cities with growing populations, the shortage of housing can quickly become a crisis. One recent survey indicated that two in five Londoners would consider taking their households and talents elsewhere due to the lack of affordable housing. That figure is predicted to rise to half of all London employees if prices continue to increase.


If we have reached any consensus on the issue, it is that supply needs to be increased, dramatically and urgently: only then will house prices become affordable for the public. But beyond that, there is little agreement as to how we solve the problem.

As cities grow, the infrastructure and institutions that support residents need to keep pace as well. London’s competitiveness relies not just on affordable housing, but on good public facilities, including modern hospitals and schools. Nearly 60 per cent of Londoners who polled in a survey we conducted last year said that our public facilities need to be refurbished.

We could help solve both these problems at once – by building above existing buildings from libraries to schools to hospitals, whilst regenerating them for Londoners at the same time. The city gets the housing it desperately needs; our public buildings get much needed TLC – or in some cases, completely remade for the 21st century.

Here’s how it would work. A private developer would upgrade the local library, for example, and pay for the work by building new homes, on top which they can then sell or rent. There are a number of examples both at home and further afield – in New York for example – of this working very successfully.

According to our calculations, you could provide around 630,000 new homes across London in this way, which comfortably meets the 488,000 homes needed until 2024.

Which boroughs have the most public buildings that we could build up? Image: WSP | Parsons Brinckerhoff.

Obviously it won’t be possible or desirable to apply this to every hospital, school and fire station – but the potential is so huge that, even if only a fraction could be targeted, it would still have a major impact in helping cities maintain their social functionality. The key here is to maintain school, health, police, cultural infrastructure alongside increasing density, enabling expanding neighbourhoods and cities to prosper.

Consider Lambeth, which has the best records for public land. Our research suggests a “residential unit potential” of around 31,400 new homes if all municipal land potential could be realised with 12 additional floors; or 15,575 with six extra storeys. With a mixed height strategy (a combination of the two), there would still be twice the potential to meet the entire 2021 monitoring target and estimated capacity deficit combined (between them, they add up to 9,835 homes).

Perhaps more realistic capacities can be calculated from looking at the subcategories of central government assets, council buildings, policing, and libraries, which would be more suitable for residential buildings above them. Combined these would create 8,850 new homes with six further storeys, and 17,700 new homes with 12 further storeys. With a mixed height solution this approach could also provide the required 2021 target for Lambeth.

An artists’ impresson of some flats above an (admittedly rather small) hospital. Image: WSP | Parsons Brinckerhoff.

Perhaps the biggest hurdle to overcome is cultural or psychological: living above these buildings isn’t for everyone. However, when surveyed 63 per cent of Londoners said they would live above a library, and 23 per cent above a hospital or school. There’s even a market for the 8 per cent of Londoners who would live above a prison.

This idea is not a panacea – but it could form part of a wider strategy that stimulates creative ways to solve the housing crisis. There are a lot of places where we can build homes in London, without sacrificing what makes the place attractive in the first place – we just have to find them. Otherwise, the best and brightest may look elsewhere.

Bill Price is director of construction consultancy WSP | Parsons Brinckerhoff. The firm’s “Housing over public assets” report can be read here.