New research conducted by Knight Frank has found that as many as 41,000 new dwellings could be built in central London using rooftop development space, without altering the iconic skyline. The study, which uses the latest geospatial mapping software, highlighted that more than 28m sq ft of potential additional residential floor area could be developed, with this airspace having a potential value of £51bn.

Stimulated in part by the 2017 Housing White Paper, the research project aimed to identify the extent of the Government’s pledge to seek out opportunities for higher-density housing in urban locations particularly where buildings can be extended upwards by using the ‘airspace’ above them. In response, Knight Frank has developed ‘SKYWARD’ – a method to systematically analyse the potential of each building.

SKYWARD analyses 3D spatial data from the Ordnance Survey. It cross references Land Registry data to assess ownerships and Historic England data to filter out listed buildings.

Representing the sheer scale of the opportunity, some 23,000 buildings could be suitable for rooftop development in Zones 1 and 2, and the volume of the unused plots across the same area is equivalent to eight Burj Khalifa towers (830m high), crucially without the corresponding impact on London’s skyline.