How new permitted development rights allowing upwards extensions could affect the system

What opportunities and challenges would a proposed new permitted development right allowing new housing via upwards extensions present for applicants and authorities, Stuart Watson asks.

Over the course of this parliament, the expansion of permitted development (PD) rights has become a highly contentious subject in the planning sector. The government justifies the controversial policy of allowing developers to convert buildings to residential use without the need for a planning application by pointing to the substantial number of additional homes delivered since its introduction. And ministers continue to explore further avenues for expanding PD.


The latest such initiative emerged in the form of a consultation, published alongside the Budget in October, entitled Planning Reform: Supporting the high street and increasing the delivery of new homes.


The document invites views on a range of possible changes to PD rights and use classes that aim to revive town centres, including a new right to extend buildings upwards to provide new homes.


The consultation sets out three options for upwards extensions using PD rights. The first – and most limited – proposal suggests that development could be permitted above terraced buildings where there is at least one higher adjoining building, with the maximum height determined by the main roofline of the highest building. The document also moots an alternative approach to "permit upwards extensions more widely to a height no higher than the prevailing roof height in the locality".


In both cases, it is proposed that the building height once extended should be capped at a maximum of five storeys from ground level. A third option suggests that free-standing blocks of residential flats of more than five storeys could be extended upwards under the PD regime, and canvasses opinions on whether there should be a limit on the number of additional storeys that could be added, citing five as an example.

Developers would have "some interest" in taking advantage of such rights, says Andrew Whitaker, planning director at the Home Builders Federation. "They would allow for more mixed-use development in areas that are currently mono-tenure because they could open up lots of opportunities for building upwards in town centres, many of which are low-rise and could have another level of residential above them." he says. "These PD rights can generate a significant amount of residential development."


Housing associations would be likely to focus on the opportunities that could be provided by the right to extend free-standing blocks of flats, suggests Duncan Neish, policy officer at social landlord umbrella body the National Housing Federation. "We have to take into account the logistical difficulties of doing that in a block where people are already living," he says, "but it might be of interest to some of our members doing regeneration, because instead of knocking a block down, they might choose to refurbish it and add extra stories on top."


In negotiating such a regime, there would be a number of practical challenges involved for both developers and local authority planners, however. Projects to extend upwards above existing buildings are often complex in both structural and regulatory terms, involving a range of factors including the strengthening of walls and foundations, party wall issues, compliance of older structures with building regulations, heritage considerations, neighbours’ right to daylight and overlooking.


Developers wishing to build under PD rights must apply to the local planning authority for prior approval, and the list of criteria that upwards extensions would need to meet could be a long one. "As was highlighted in the response to the consultation on upward extension proposals for London in 2016, the prior approval process that would be required to protect neighbours and the character and amenity of an area would result in a permitted development right process that would be very close to that required for a planning application," comments Mike Kiely, chair of the Planning Officers Society, which represents public sector planners. "This hasn’t changed."

In its response to the 2016 consultation, which was limited in scope to the capital, the government concluded that building up had a role to play in providing new homes not just in London, but across the country. But instead of proceeding with the proposed new PD, it said it would "take forward the policy option through the National Planning Policy Framework" (NPPF). Consequently, July’s revised NPPF required planners to "support opportunities to use the airspace above existing residential and commercial premises for new homes", and the issue appeared to have been settled until the appearance of the new consultation paper.


"I had wondered whether government had decided it was too difficult to draft a PD right that is useful for landowners and developers, but provides sufficient protection for local residents, so I was surprised to see it re-emerge," says Simon Ricketts, partner at law firm Town Legal. "The potential difficulty is probably part of the reason why we have had a few stalled attempts at introducing it."


The consultation paper recognises that factors including the design, siting and appearance of the extension and its impact on the character of the area would need to be considered at the prior approval stage. "As soon as you introduce matters into the process that are essentially subjective, then you give the local authority quite a bit of power to push back, and developers may find it is no easier than making a planning application," warns Ricketts.


Planning authority managers may be dismayed by the prospect of being forced to engage in complex prior approvals proceedings that carry a lower fee than would be payable for a planning application: "In the past, we have seen developers going down that route because it is cheaper, but the burden on the local authority doesn’t change. You still do the same processes, but don’t get the fee income for it," says the District Councils’ Network planning lead Daryl Phillips. He cautions that, if local people perceive that there is a "free-for-all" on upwards extensions in their areas, then there will be public pressure on councils to make article 4 directions to restrict the scope of PD.


"It is interesting to set side by side this light-touch procedure, in relation to proposals that will undoubtedly have a visual impact on their surroundings, and the government’s announcement of the Building Better, Building Beautiful commission led by Sir Roger Scruton," says Ricketts. "That seems to suggest closer attention will be paid to issues of aesthetics and design in relation to planning, so the government is, as is often the way, facing two ways."


The consultation concludes on 14 January and it is not certain that when the responses are in that ministers will deem the proposal to be necessary or practical. Some observers will also be watching the outcome for an indication of which priority – improving the design of new developments or increasing housing numbers – currently carries more weight among government policy-makers.