Raising the roof: Government reveals well-intentioned, albeit not simple, permitted development rights

Tetra Tech’s planning team shares an in-depth look at the Government’s new permitted development rights.

Advancing its ‘build, build, build’ agenda, the Government has introduced a new permitted development right (PDR) allowing two stories of upward extensions to existing purpose-built residential blocks of flats. The change will take effect 1 August.

The announcement forms a key part of the Government’s push to revitalise the economy as we emerge from lockdown.

While this change is overall positive on paper, upwards extensions need to meet certain criteria, subject to prior approval – specifically, a formal submission to local planning authorities requesting approval of specified parts of a development before work can commence.

Several interesting criteria stand out:

  • The right is restricted to buildings of three storeys or more in height. The extended building must not exceed 30 metres in height (excluding plant). Meanwhile, the height of the extension cannot exceed 7 metres compared to the highest part of the existing roof, whereas any new storeys must each be no more than 3 metres in height.
  • The right extends to purpose-built, detached blocks of flats built after 1 July, 1948 and before 5 July 2018, when consultation on this new PDR was announced.

The Order expressly excludes buildings converted to residential via certain PDRs, but ‘purpose-built’ is defined – meaning buildings converted from the use for which they were built do not benefit, whether they received planning permission or not.

  • The extension must only be on the principal part of the building and not extend beyond the curtilage of the existing building.
  • The existing flats must not be or form part of a listed building or scheduled monument, or land within its curtilage. Furthermore, they must not lie in a conservation area.
  •  New floorspace created will be liable for the Community Infrastructure Levy.

Development is only permitted subject to prior approval, and the devil is in the details as far as the conditions go. The developer must assess a series of factors, including transport, highways, contamination and flood impacts, all of which we have become accustomed to following amendments to the office to residential PDR.

However, there are further considerations regarding the impact on the amenities for existing residents and neighbours, including the provisions of natural light, as well as any impact on air traffic and protected vistas (in London). This appears to open the door to requests for documents addressing a wide variety of matters or details. It will not cause difficulties if both parties have the same idea about what the local planning authority (LPA) may ‘reasonably require’ to assess relevant matters.

Design has always been an overarching concern with permitted development, and quality of accommodation. Research indicates that office-to-residential PDR has led to accelerated housing delivery but also heavy criticism over reduced living space quality (no meaningful private amenity and poor-quality daylight), lower levels of affordable housing, and lacking developer contributions. Nothing exemplifies this better than the planning inspector who allowed windowless flats in Watford because he ‘lacked grounds for their refusal’.

So, whilst the PDR has boosted housing supply, sceptics will argue that past PDRs have sacrificed liveability, beauty, and sustainability, compared to schemes governed through full planning permission.

Had the new PDR not been subject to design scrutiny, this would have potentially diluted the Government’s commendable drive for higher-quality design standards. The measures included through the PDR, however, mean the authority will have a say on matters like the building’s external appearance, the provision of adequate natural light in all habitable rooms, and the impact on the amenity of the existing building and neighbouring premises. All of this is a step forward.

The LPA may refuse the prior approval application if it considers that the development does not benefit from the PDR, or if insufficient information has been submitted. Under such circumstances, the application may be appealed.

In principle, the PDR represents a promising step towards boosting supply and speed of housing delivery, especially in light of the prevailing notion that we are not building enough houses. Rooftop development could prove a substantial additional source of housing delivery. Building new homes at roof level has clear advantages in terms of cost and value, both to developers and occupiers. Building without groundworks, site remediation, and sub-structure offers significant cost savings. Whilst providing often panoramic views of central London from rooftops is highly desirable and will have obvious advantages in terms of capital value and rental terms, this approach is by no means limited to central London.

Having said that, rooftop development could bring about other obstacles that need addressing, including access, fire safety, maintenance, acoustics, services, sustainable technology, and construction methods. Existing building capcity to support additional loading will fundamentally determine the feasibility of delivering rooftop development, with each site having unique conditions.

Would any utilities and plant or PV panels located at the top of the building need to be moved, and if so, how will this be done? There are also logistics in carrying out complex building works whilst existing occupiers remain in residence at the lower floors – how can this be done in practice and be evidenced in terms of what is submitted to the local authority as part of the prior approval process?

The Government’s announcement is clearly well-intentioned, but given the requirements and exemptions set out in the regulations, the new rights are perhaps not quite so simple as they first appear, applicable only in fairly limited circumstances. For this reason, we expect that take-up to be small, though it could act as a useful fallback position for developers and landowners when discussing redevelopment if it can be demonstrated that prior approval is likely to be granted.

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