Do I Need Planning Permission for a Rear Extension?

Most rear extensions in England do not need planning permission. Under permitted development rights, homeowners can extend the rear of their property without submitting a planning application — as long as the extension stays within certain size and height limits.

• Extends no more than 3 metres from the original rear wall on semi-detached or terraced houses
• Extends no more than 4 metres on detached houses
• Maximum height does not exceed 4 metres
• Eaves height does not exceed 3 metres
• Does not cover more than half the garden
• Materials match the existing house

• Extends no more than 3 metres from the original rear wall
• No closer than 7 metres to the rear boundary
• Roof pitch matches the existing house
• No upper floor side-facing windows within 2 metres of a boundary

• Property is a flat or maisonette
• Property is a listed building
• Extension exceeds the size limits above
• Permitted development rights removed by Article 4 direction
• Original planning permission conditions restrict PD rights

Since 2020 there is a prior approval route for larger extensions — up to 6 metres on semi-detached and terraced houses, and up to 8 metres on detached houses. This is not full planning permission but does require council notification.

In conservation areas, permitted development rights are more restricted. Listed buildings always require listed building consent regardless of size.

Every project is different. Dimensions, property type, location and previous extensions all affect whether you need permission.