Frequently Asked Questions - Permitted Development

Back in 2008, Permitted Development Rights were extended so that they now include the majority of typical house extensions. The objective was twofold:

  • To remove the red tape and expense of the planning system in relation to uncontentious building work

  • To reduce the burden on local Planning Departments

In order that your extension should qualify under permitted development rights it would need to satisfy all the following criteria:

  • No more than half the area of land around the "original house"* would be covered by additions or other buildings.

  • No extension forward of the principal elevation or side elevation fronting a highway. 

  • No extension to be higher than the highest part of the roof. 

  • Maximum depth of a single-storey rear extension of three metres for an attached house and four metres for a detached house. 

  • Maximum height of a single-storey rear extension of four metres. 

  • Maximum depth of a rear extension of more than one storey of three metres including ground floor. 

  • Maximum eaves height of an extension within two metres of the boundary of three metres. 

  • Maximum eaves and ridge height of extension no higher than existing house. 

  • Side extensions to be single storey with maximum height of four metres and width no more than half that of the original house. 

  • Roof pitch of extensions higher than one storey to match existing house. 

  • No verandas, balconies or raised platforms. 

  • On designated land** no permitted development for rear extensions of more than one storey; no cladding of the exterior; no side extensions.

* The term "original house" means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Although you may not have built an extension to the house, a previous owner may have done so.

** Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.

If  your extension does not conform to these criteria, that does not mean you cannot build, you will simply first need to apply for and obtain planning permission.

Most homes in the UK could benefit from Permitted Development Rights, which householders to build certain types of structures without first having to obtain planning permission.

Permitted structures are of ten of a minor nature but some can be quite significant, such as a swimming pool or a summer house in your garden. There are strict rules for anything to qualify under Permitted Development Rights and the structure must be 'incidental to the enjoyment of the dwelling'. In other words, their use must be secondary to the main dwelling and must not constitute a separate property.

Although you don't need planning permission for a structure that qualifies under Permitted Development Rights, it is none the less advisable to obtain a 'Certificate of Lawfulness'.

To obtain a certificate, you must submit your drawings to the local authority, who will check them against permitted development constraints. Although this may sound like a similar process to a Planning Application, it is actually far less onerous.

You may be wondering if it is worth applying for a 'Certificate of Lawfulness' if it is not essential. The real value is, if and when you decide to sell the property and a search is made that flags up that the structure does not having planning permission the certificate is the document that makes everything clear and above board.

It should be noted that structures which qualify under Permitted Development Rights are still subject to Building Regulations and therefore you need to seek professional advice before going ahead with the Construction.  Contact Jonathan who will be happy to explain how he can be of service.

For examples of completed projects please visit the Projects page of this website. 

For a summary of the services that Jonathan provides and how he can help you with your project please visit the Services page of the website.  

Contact Jonathan on: 01395 265768 or email:

Click here to return to the Home page

Copyright 2023 Jonathan Braddick  - RIBA  Architects Devon.  3 Southernhay West, Exeter, Devon, EX1 1JG   Tel:  01395 265768    Web:   email: