Guide
Do I need planning permission for an extension?
Many single-storey extensions don’t need a full planning application, thanks to permitted development rights. Here’s what that means, the limits that apply and when you do need to apply.
What is permitted development?
Permitted development rights let you make certain changes to a house without applying for planning permission, as long as you stay within set limits. They apply to houses, not flats or maisonettes, and they can be removed or reduced by the council.
Single-storey rear extensions
- Up to 3 metres beyond the original rear wall for a semi-detached or terraced house, or 4 metres for a detached house.
- Up to 6 metres or 8 metres through the larger home extension (prior approval) scheme, where you notify the council and neighbours can comment.
- No higher than 4 metres.
- If within 2 metres of a boundary, the eaves can be no higher than 3 metres.
- Extensions and outbuildings together can’t cover more than half the land around the original house.
- Materials should look similar to the existing house.
Side extensions
- Single storey only, no higher than 4 metres.
- No wider than half the width of the original house.
- Always need planning permission in a conservation area.
When you do need planning permission
- The extension is bigger than the limits above.
- Two-storey extensions in most cases.
- Your home is in a conservation area and the work affects the outside, or is covered by an Article 4 direction.
- The house is listed (you’ll also need listed building consent).
- Permitted development rights were removed when the house was built or previously extended.
“Original house” means the house as first built, or as it stood on 1 July 1948. Earlier extensions count towards the limits.
Building regulations are separate
Even when you don’t need planning permission, an extension always needs building regulations approval, covering structure, insulation, fire safety, drainage and ventilation. We arrange building control as part of every job.
Local councils
Planning for Ware, Hertford and Stanstead Abbotts is handled by East Hertfordshire District Council. Hoddesdon and Cheshunt fall under the Borough of Broxbourne. The national rules are on the Planning Portal.
If you’re unsure, a Lawful Development Certificate confirms your extension is permitted development, which helps when you sell. We can apply for one on your behalf through our architectural service.
Source: Planning Portal, extensions. This guide covers England and is a summary, not legal advice.
Common questions
Do I need planning permission for a single-storey rear extension?
Not usually, if it’s within 3 metres (semi-detached or terraced) or 4 metres (detached) of the original rear wall, no higher than 4 metres, and your home isn’t in a conservation area, listed or covered by an Article 4 direction.
How big can a rear extension be without planning permission?
Up to 3 metres deep for semi-detached and terraced houses, 4 metres for detached, and up to 6 or 8 metres through the prior approval scheme. It also can’t take up more than half the land around the original house.
Do I need building regulations for an extension?
Yes. Every extension needs building regulations approval, whether or not it needs planning permission.