Many extensions in England don't need a full planning application because houses have permitted development rights. Whether yours does depends on the type of home, the size of the extension and where you live.
Single-storey rear extensions
- Up to 3 m deep (semi-detached or terraced) or 4 m (detached) is usually permitted development.
- Up to 6 m / 8 m is possible through the larger home extension prior approval route. Neighbours are notified and the council decides within 42 days. This route isn't available in conservation areas.
- Maximum 4 m high, and eaves no higher than 3 m within 2 m of a boundary.
Two-storey and side extensions
- Two-storey rear: up to 3 m deep, and at least 7 m from the rear boundary.
- Side: single storey only, no more than 4 m high and no wider than half the original house.
- Neither is permitted development in a conservation area.
When you always need planning
- Flats and maisonettes, which have no householder permitted development rights
- Listed buildings, which also need listed building consent
- Where rights are removed by an Article 4 direction or a planning condition. This is very common on estates built in the last 15–20 years.
Even if it's permitted development…
Get a Lawful Development Certificate. It proves the extension was lawful, which your buyer's solicitor will ask about when you sell. Building regulations approval is needed either way.
Try our free feasibility check, or get planning drawings from £650.
A general guide to the rules for houses in England. Your own case depends on your property's planning history. We check it as part of every quote.