Building above rail lines could result in the creation of around 250,000 new homes in London, according to a report out today.
Meanwhile, another new piece of research said car parks too are ripe for development, with the potential to build around 400,000 homes on car parks across the UK, 75,000 of which would be in London.
Property services giant JLL and engineering professional services firm WSP have come up with two routes to easing housing troubles in the capital, and further afield.
WSP boldly states that there is potential to provide "all the new homes London needs" if existing engineering techniques were used to construct apartment blocks directly above rail, Overground and Underground lines.
It has identified all rail tracks in Transport for London's (TfL) fare zones one to six where there are no breaks in the track made by tunnels, roads or bridges, and where there was 10m of available land on both sides.
WSP said this would allow for the development of 100m² apartments in buildings rising to 12 storeys.
"If a conservative 10 per cent of this total was delivered, it would provide 250,969 homes," the report states.
The London boroughs of Brent, Ealing and Croydon, and TfL zones two, three and four have the most overbuild development potential.
Rail lines with development potential:
Number of hectares available by borough:
Bill Price, WSP director, said:
We have to be more creative in using existing space in what remains a relatively low-rise city.
The air rights above rail tracks present an unrealised but significant opportunity to build more new homes on brownfield land. It’s important to emphasise the engineering is absolutely possible and not new. We have been working on projects of this nature in New York for decades.
Right now in London we are working on a variety of projects that rise above rail lines including a 50-storey residential tower, homes above a new Crossrail station and even a Premier League stadium.
Here's what rail overbuild could look like if implemented in different spots in London:
WSP compiled the report after Network Rail appointed the firm back in 2012 to study the feasibility of building above rail lines, focusing on the type of decking, as well as noise and vibration issues.
Meanwhile, JLL says the UK is in the midst of a housing crisis fuelled by an "acute imbalance" between supply and demand, with a notable lack of available development in land in locations where new housing is needed most.
It has identified just under 10,500 car parks in the UK's towns and cities with the possibility to accommodate up to 400,000 homes, "enough to house circa one million people". Of those, 75,000 would be in London.
In the majority of these, JLL said it was possible to build without the loss of parking spaces.
Noting a study by the Organisation for Economic Co-operation and Development modelling the projected rise of driverless cars and the steep drop expected in privately-owned cars, the report said declining car ownership could then free up parking to be used for other uses.
More than half of the car parks identified are in public ownership, under the control of local authorities.
"This may mean that government has directly within its means the ability to enable circa 200,000 homes to be built on urban car parks," said JLL residential research director Nick Whitten.
Would it work?
Melanie Leech, chief executive of the British Property Federation, said London's housing shortage continues to undermine the capital's capacity to increase productivity.
"We need all housing tenures firing on all cylinders to make meaningful change and this includes looking at all options available to free up land," she said.
Railway land is already being considered in the context of major infrastructure schemes such as HS2 and, at a time when London needs 50,000 new homes every year, building over rail lines may offer a viable solution that should be taken seriously.
Car parks are often in city centre locations – and so, as London looks to regenerate, modernise, and offer more accessible housing in central locations, car parks must be a part of the solution.
Also, new technology and the mayor’s drive to combat pollution likely mean cars will increasingly disappear from the city centre. It will then make sense to repurpose car parks for new homes, offices, leisure or community facilities, as local need dictates.