Rear extensions
Single-storey rear extensions
The most common extension we build, and often the simplest to get approved. A rear extension opens up the back of your home to the garden and creates the open-plan space most families want.
Why a rear extension?
Extending at the back usually has the least impact on neighbours and the street, which is why many rear extensions can go ahead under permitted development. It’s also where most homes need space: the kitchen, dining and family room.
- Up to 3 metres deep on semi-detached and terraced houses under permitted development (4 metres detached)
- Up to 6 or 8 metres through the prior approval scheme
- Flat roofs with rooflights, or pitched roofs to match the house
- Full-width glazing or bifold doors to the garden
How far can I extend the back of my house?
| House type | Permitted development | With prior approval |
|---|---|---|
| Detached | Up to 4 metres | Up to 8 metres |
| Semi-detached or terraced | Up to 3 metres | Up to 6 metres |
Measured from the original rear wall of the house. The extension can be no higher than 4 metres, and the eaves no higher than 3 metres within 2 metres of a boundary. Conservation areas, listed buildings and homes where permitted development rights have been removed have different rules. Source: Planning Portal. Read our full planning permission guide.
Common questions
Do I need planning permission for a single-storey rear extension?
Often not, if it stays within the permitted development limits above and your home is not in a conservation area, listed, or covered by an Article 4 direction. If you want to go deeper, the prior approval scheme lets you notify the council instead of making a full application. You always need building regulations approval.
How much is a single-storey rear extension?
As a guide, our single-storey rear extensions typically cost [Geoff: typical range]. See our extension costs guide for what affects the price.
Can you build on top of a single-storey extension later?
Sometimes. The foundations and structure need to be designed for it from the start, and a second storey will normally need planning permission. If you think you might want to build up later, tell us at the design stage.