In England, many house extensions can be built under permitted development (PD) without a full planning application. This guide summarises the usual rules. If your property is in Wales, read planning permission in Wales instead, as the rules are different.
These rules are for England and are general guidance. They can change and local restrictions apply, so confirm with the local planning authority or a planning professional, or apply for a Lawful Development Certificate.
Typical PD limits for a single-storey rear extension in England
For houses (not flats or maisonettes) that have not lost their PD rights:
- Depth: up to 3 metres for attached and semi-detached houses, and 4 metres for detached houses
- Larger home extension scheme: up to 6 metres (attached/semi-detached) or 8 metres (detached) can be built through a prior approval process, which includes neighbour consultation
- Height: maximum 4 metres overall, and eaves height of 3 metres if the extension is within 2 metres of a boundary
- Materials: similar in appearance to the existing house
- Coverage: buildings must not cover more than half the garden area around the original house
- Position: not forward of the principal elevation (usually the front) or the side facing a highway
Side extensions and two-storey extensions
- Single-storey side extensions are allowed within limits, such as not being wider than half the width of the original house
- Two-storey rear extensions have tighter rules, including distance from the rear boundary (commonly 7 metres), a roof pitch matching the existing, and upper-floor side windows that are obscure glazed and non-opening below a certain height
When PD rights do not apply
- Flats and maisonettes
- Conservation areas and other designated land, where limits are stricter and some rights are removed
- Listed buildings
- Houses where PD rights were removed by a condition or an Article 4 direction
- Houses that have already been extended close to the limits
Prior approval for larger extensions
The larger home extension scheme asks you to notify the council, who consult adjoining neighbours. If neighbours object, the council considers the impact on their amenity. The process takes up to around 42 days. It is not a full planning application.
Lawful Development Certificate
A Lawful Development Certificate confirms that your project is lawful under PD. It is optional but useful for buyers and solicitors when you sell.
What else you need
- Building regulations approval for almost all extensions
- A party wall agreement if you build on or near the boundary
- Realistic budget and programme: costs and timeline
Wales versus England
If you are comparing both systems, see Building in Wales vs England.
Planning an extension in England?
Abron Contracting is based in Newport, South Wales and takes on projects in England. We can review your plans, explain what approvals are likely to be needed and provide a quote. Contact us or call 01633379170.
Frequently asked questions
How far can I extend without planning permission in England?
Typically up to 3 metres at the rear for attached and semi-detached houses and 4 metres for detached houses, with larger depths possible through the prior approval scheme.
Do I need planning permission for a two-storey extension in England?
Often yes, because limits are tighter, though some can be built under PD. Check the specific limits.
What is the larger home extension scheme?
A prior approval process that allows single-storey rear extensions of up to 6 or 8 metres, subject to neighbour consultation.
Do conservation areas have different rules?
Yes. PD rights are reduced in conservation areas and other designated land.
Do I still need building regulations?
Yes. Building regulations approval is separate and is needed for almost every extension.
