London’s rooftops may hold the answer to the challenges caused by a shortage of residential property. Geospatial analyst Robert Holden explains how Knight Frank’s Skyward report is informing this fast-developing debate.
At a time when the availability of land is becoming constrained, our research shows that at least 41,000 new homes could sit in the voids created by central London’s uneven rooflines. Importantly, this development potential could be realised without affecting the city’s unique character. Knight Frank’s Skyward Report is intended to encourage discussion about rooftop development and inform what is still a niche form
Skyward was inspired when Knight Frank was instructed to sell the roof space at Lords View One, adjacent to the famous London cricket ground, where developing the roof would involve upgrading works to the block, including new lifts, windows, common parts, parking, and landscaping. Further stimulation came following the 2017 Housing White Paper. Indeed, our research project aimed to identify the extent of the Government’s pledge within the White Paper to seek out opportunities for higher-density housing in urban locations, particularly “where buildings can be extended upwards by using the ‘airspace’ above them”.
Since the release of Skyward, Sajid Javid, Minister for Housing, Communities and Local Government, announced the revised draft National Planning Policy Framework would support rooftop development. This underlines the importance of our research. An endorsement of ‘3D infill’, in which upward development is generally considered appropriate if it does not exceed the adjacent roof height, has the potential to add an objective approach to planning decisions. It would also allow developers and owner-occupiers to know the space and value proposition of their rooftop extension much earlier in the planning process.
Digital mapping technology continues to transform urban planning. Skyward uses Ordnance Survey data to systematically analyse the scale of rooftop development opportunity in central London. The motivation for it was to encourage a collaborative approach by exploiting the increasing supply of high quality geographic data now readily available to the industry. The recent announcement of a new government Geospatial Data Commission will further remove obstacles to organisations sharing both the data and ideas behind this research. Skyward exemplifies how geographic data can provide new understanding and has set the groundwork for an industry-wide view of how rooftop development opportunities and constraints are identified.