Tools · Do I need planning permission?

Do you need planning permission for a rear extension?

A single storey extension on the back of a house can often be built without planning permission, within strict limits on depth, height and position.

Across the 333 councils we track, 84% of 206,250 decided rear extension applications were approved, and typical council decision times run 8 to 9 weeks (public planning record to 15 Jul 2026).

First, about your home

What kind of home is it?

These permitted development rights apply to houses. Flats and maisonettes do not have them.

Is the building listed?

Work to a listed building usually needs listed building consent as well as planning permission. Outbuildings and boundary walls within the grounds of a listed building also need permission.

Is your home in a conservation area, National Park, the Broads, an area of outstanding natural beauty, or a World Heritage Site?

The rules call this designated land. Several permitted development rights are reduced or removed there. If you are not sure, your council's website says which areas are designated.

Now, about a rear extension

How far will it extend beyond the original rear wall of the house?
Will any part of it be taller than 4 metres?
Will it come within 2 metres of a garden boundary with eaves higher than 3 metres?
Is any of it at the front of the house, facing the road?
Counting existing extensions and outbuildings, will more than half of the land around the original house end up built on?

0 of 8 questions answered. Answer them all to see where your project stands. Not sure is always an option.

What actually happens in your council

If you do end up applying, real decisions show what to expect. Pick your council for its approval rate and typical decision time for rear extension applications, from the public planning record.

The rules this checker tests, cited

England’s permitted development limits for a rear extension, checked against the official guidance on 2026-07-17. Every rule links to its source.

Building Regulations are separate from planning. A rear extension needs Building Regulations approval regardless of planning: structure, insulation, drainage and electrics are all covered.

If permission is needed: usually a £548 application in England (fees from 1 April 2026, indexed each year, per the official fee guide (opens in new tab)). A Lawful Development Certificate for a proposed project is £274.

If you take it forward

Real planning history beats promises. See which architects and agents know your council, check approval odds by council and project, or browse traders with public evidence:

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Common questions

Do I need planning permission for a rear extension in England?

Often not: A single storey extension on the back of a house can often be built without planning permission, within strict limits on depth, height and position. Every limit has to be met, the rights apply to houses (not flats), and they can be removed locally by an Article 4 direction or a condition on an earlier permission. A Lawful Development Certificate from your council is the way to be certain.

How far will it extend beyond the original rear wall of the house?

A single storey rear extension can extend up to 4 metres beyond the original rear wall of a detached house, or 3 metres for any other house. Up to 8 metres (detached) or 6 metres (other houses) can be possible under the larger home extension rules, which need prior approval from the council after your neighbours are consulted. “Original” means the house as first built, or as it stood on 1 July 1948. Source: GPDO Schedule 2, Part 1, Class A, paragraphs A.1(f) and A.1(g).

Will any part of it be taller than 4 metres?

A single storey rear extension must not be taller than 4 metres. Source: GPDO Schedule 2, Part 1, Class A, paragraph A.1(f).

Will it come within 2 metres of a garden boundary with eaves higher than 3 metres?

Within 2 metres of any boundary, the eaves of the extension must not be higher than 3 metres. Source: GPDO Schedule 2, Part 1, Class A, paragraph A.1(i).

Is any of it at the front of the house, facing the road?

Extensions are not permitted development in front of the principal elevation (the main front of the house). Source: GPDO Schedule 2, Part 1, Class A, paragraph A.1(d).

How much does a planning application for a rear extension cost?

If permission is needed, this kind of project is usually a £548 application in England (fees from 1 April 2026, indexed annually). A Lawful Development Certificate for a proposed project costs half the application fee.

Guidance from the public rules, not legal advice. Your council has the final say. The rules on this page are England law; Wales, Scotland and Northern Ireland have their own versions.

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