With the challenging target set by the Mayor of London for 65,000 new homes a year across this fast growing but already overcrowded city where land is at a premium and brownfield sites are becoming more scarce, innovative approaches to finding development sites are resulting in an increasing pressure to use space more efficiently by building upwards and over land that is already utilised for transport.

Sadie Morgan, Founding Director of dRMM and member of the National Infrastructure Commission, said:
“The pressure on London to deliver the homes and jobs needed for a growing population will require intensification and intelligent planning in the coming decades.”

Sian Berry AM, Chair of the London Assembly Housing Committee, agrees:
“Thinking outside the box is necessary with the urgent demand for more affordable homes in London.”

Rooftop Developments
Utilising the gaps that appear in the roofline on a street where there is a mix of low and mid-rise buildings by constructing additional homes on top of these existing properties provides a solution to increasing density without requiring more land. Knight Frank’s ‘SKYWARD’ modelling cross-references Ordinance Survey and Land Registry data to create a 3D model of these empty spaces and predicts that in Zones 1 and 2 there is capacity in the roofline for 40,000 new homes with a potential value of over £51bn. Apex Airspace estimate there is space for 140,000 new homes across Greater London.

Iceni Projects note that Policy 118(e) of the revised National Planning Policy Framework states the government’s support for the use of airspace above existing residential and commercial premises for new homes. Inevitably, such an ambitious approach would not be without its challenges; however, by employing intelligent design and considerate construction it could have a viable future. For example, setting additional floors back from the edge of the existing building could mitigate concerns about overshadowing and consequent impact on sunlight; using modular construction would be less disruptive as it offers faster delivery and a shorter time on site.

Over-Station Developments
Another solution is to build developments over and around railway stations, which occupy large amounts of land, to deliver new homes and facilities to local communities. Successfully completed over-station developments which prove that this is both viable and attractive include Liverpool Street and Charing Cross which have major commercial offices constructed over the stations.

Francis Salway, Chairman of the Property Advisory Group of Transport for London, said:
“Over station development ticks so many of the boxes in terms of good urban planning as well as having the potential to make a quantum change in the provision of homes and work space.”

There is also a benefit to the transport network from over-station development as it provides a revenue to reinvest in the rail infrastructure; for instance, Transport for London aims to realise £3.4bn in non-fare revenue, much of which will come from land development.

Richard Brown, Research Director at Centre for London said:
“developing at and around new and existing stations cannot be neglected – as a sustainable form of development, as a source of funding for new and improved infrastructure, as a means of creating mixed-use urban centres at transport hubs, and as a way of strengthening and connecting communities.”

Iceni Projects
Centre for London report Ideas above your Station: Exploring the Potential for Development at London’s Stations https://www.centreforlondon.org/project/over-station-development
Knight Franke Report: Skyward – Identification of Rooftop Development Opportunities