Brownfield development, which means building on derelict land that has previously been used, is increasingly taking centre stage when it comes to tackling the housing crisis. A package of £1.8bn has recently been announced for new homes on this kind of land. But less is spoken about the role for airspace developments – a sustainable, high-density solution to housing delivery where additional storeys are placed on top of existing buildings. As more is being made about the need to build upwards, not outwards, airspace could become a crucial part of the solution to delivering new London homes in the near future.
Last year, the government introduced new rules allowing apartment blocks to be extended by up to two floors without the need for obtaining planning permission. This presents a real opportunity for airspace developments to take centre stage. As an appetite for these kinds of developments grows among local authorities, airspace is beginning to take off across some locations, with predictions that London has space for over 180,000 of these homes.
Property developers are getting interested. Apex Airspace has projects of this kind in Tooting and South Hampstead, overlooking Abbey Road. Perhaps the most well-known airspace proposals are Transport for London’s plans for new homes on top of its stations.
Traditionally, brownfield developments have had the associated benefits of being close to existing amenities and preventing the expansion onto green spaces. Airspace developments take this a step further. With much of the existing structure already standing, airspace can be completed at an average of 50 percent quicker than building from scratch, while residents can benefit from facilities that are already available quite literally within their own building.
Airspace developments have knock-on impacts for the whole site’s upkeep, encouraging the creation of new communal facilities that benefit all residents. The new Tooting development means the building will get a new lift and stairwell.
The increasingly popular modern methods of construction are perfectly suited to these kinds of developments. Homes can be built off-site before being slotted seamlessly onto the top of buildings. New technologies mean it’s possible to calculate the optimal design, density and massing that suits both the requirements of the existing building and the needs of its residents.
Modular homes also come with a plethora of environmental benefits, including producing an average of 12 percent less carbon emissions than their traditional counterparts. Stringent quality controls during the manufacturing process also allow for a better product overall.
Crucially, building off-site means that much-needed homes can be delivered without the kind of disruption associated with traditional housebuilding, a key concern when it comes to local opposition to new developments. With airspace developments, neighbours often don’t even have to be relocated.
Architects have the important task of ensuring that airspace developments are suited to their surrounding environment. Any additional floors should seek not just to compliment their surroundings, but actively enhance the appearance of a building’s exterior, helping to rejuvenate the local landscape in the process.
However, getting airspace developments right is not without its complexity. As highlighted earlier this year by the Association of Rooftop and Airspace Developments, local authorities often lack consensus on what the Building Safety Bill requires. For instance, it’s unclear whether sprinklers must be installed just in the airspace, or in the original building as well. Going forward, greater clarity will be needed around regulations like these if airspace developments are to emerge as a leading answer to the city’s housing crisis.
With a shortfall of now over 94,000 homes in London, airspace developments could pose a key solution. Policy is increasingly starting to move in this direction, but ensuring regulations work in its favour will be required to really get airspace off the ground.