Do You Need Planning Permission for a Rear Extension?

General guidance for homeowners in England. Last reviewed: 12 September 2026

General information, not a decision on any specific property. Confirm your position with your local planning authority before starting work. See our AI Disclaimer.

The short answer

It depends. Many single-storey rear extensions to houses in England can be built under permitted development rights — a set of national rules that allow certain works without a full planning application. But permitted development has size, height and location limits, and those rights can be reduced or removed entirely for some properties. If a proposal falls outside those limits, or the rights have been removed, full planning permission is likely to be needed instead.

What usually affects the answer

• How far the extension projects from the original rear wall of the house, and whether it is detached, semi-detached or terraced — different property types have different permitted development limits.
• Height — both the overall height and the eaves height of the extension, and its height and position relative to any boundary.
• Whether the property is flats, maisonettes, or a listed building — permitted development rights for extensions generally apply to houses, not flats, and do not apply in the same way to listed buildings.
• Conservation areas and Article 4 directions — some permitted development rights are more restricted in conservation areas, and a local Article 4 direction can remove additional rights specific to that area. The exact position must be checked for the property and proposal.
• Previous extensions or alterations — permitted development allowances are typically assessed against what has already been added to the house, not just the current proposal in isolation.
• Larger single-storey extensions — some larger rear extensions that exceed the standard permitted development limits may still avoid a full planning application via a separate prior approval (neighbour consultation) process, which has its own rules and is not automatic.

Building Regulations still apply either way

Permitted development is a planning concept — it is separate from Building Regulations. Even where no planning application is required, structural work, fire safety, thermal performance, ventilation and drainage still need to meet Building Regulations, and Building Control sign-off is typically still required.

What this means in practice

General guidance like this can tell you what to check, but not what applies to your specific property — that depends on details like your exact plot, existing extensions, local designations, and the precise dimensions proposed. Two houses on the same street can have different permitted development positions.

See also: ArchLens for homeowners & developers, Permitted development rights explained, Do you need a party wall agreement?, and our AI Disclaimer.