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New permitted development rights | Additional storeys can be built on top of existing blocks of flats

Economic Development | News

From 1 August 2020, a new permitted development right is being introduced, allowing an additional one or two storeys to be constructed on top of existing blocks of flats.

This is alongside engineering operations, replacement or installation of additional plant, construction of safe access and egress and construction of ancillary facilities, where necessary.

The ‘upward extension’ measure is being introduced with the aim of increasing housing delivery across the country in a bid to protect ‘greenfield’ land.

What are permitted development rights?

Permitted development rights allow you to make certain changes to a building without needing to apply for planning permission.

Are there any restrictions?

The permitted development right is limited in the buildings in which it can be applied to. The right will only apply to blocks of flats that:

  • are detached;
  • are at least 3 storeys in height; and
  • were constructed between 1 July 1948 and 5 March 2018.

It is important to note that the right does not apply to listed buildings, scheduled monuments or buildings within the curtilage of such. Nor does it apply to buildings within Conservation Areas, National Parks and the Broads, areas of outstanding natural beauty, or sites of special scientific interest.

If buildings do fulfil all of the criteria above, then an ‘upward extension’ can be built under permitted development. There are, however, still restrictions on what can be built out.

A full copy of the legislation can be found here.

To summarise, the restrictions are as follows:

  • The extension has to be constructed on the principal part of the building;
  • The extension cannot exceed 30 metres in height;
  • The overall roof height of the extension cannot be more than seven metres higher than the highest part of the existing roof; and
  • The internal ceiling height of each storey cannot exceed three metres, OR more than the floor to ceiling height of any of the existing storeys (whichever is the lesser height).

Prior approval

An application for prior approval will have to be made to the Council, accompanied by comprehensive floor plans and elevations. Submitting these details will satisfy the council that the design of the proposals is acceptable, in addition to adequate light being achievable. The council will then have eight weeks to determine the prior approval application.

Contact us

For advice and support on the new ‘upward extension’ permitted development rights, or any other planning query, contact Brian Mullin or Lizzie Beresford in our planning consultancy team, Marrons Planning.

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Published: 17th July 2020
Area: Development Strategy

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Marrons is a multi-service development consultancy backed by the experience of working for local authorities, extensive market intel and connections across the industry.

About Marrons

Marrons is a multi-service development consultancy backed by the experience of working for local authorities, extensive market intel and connections across the industry - from planning offices and private landowners to housebuilders and retailers.

With expertise in Planning, Architecture, Design, Heritage and Economic Development, you can trust us to lead, protect and enhance the value of your land or building assets ensuring we turn your plans into reality.

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Whether you are looking for advice on an appeal for a major development scheme, or putting in an application for a house extension, we can help you navigate the best way forward.



Led by RIBA Chartered Architects, our Architects have wide-ranging experience in handling large scale projects through multi-disciplinary teams, often acting as project co-ordinators and design team leaders.



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