If you want to add an extension to your house, you should first check if you need to apply for planning permission.
Permitted development
You don’t need to apply for planning permission if the extension meets certain rules. This is called ‘permitted development’.
The rules for permitted development depend on how many storeys (levels) your extension will have.
Single-storey extensions
If your extension will have one storey, you don’t need planning permission as long as:
- it’s located at the back of the house
- it doesn’t go back further than 3 metres if it’s a terraced house, or 4 metres if it isn’t
- the height of the eaves (where the wall meets the roof) is no higher than 3 metres
- it’s not higher than 4 metres, including sloping roofs
- it doesn’t cover more floor area than your house does
- it doesn’t take up half the ‘curtilage’ – the grounds behind your home
- it isn’t within a conservation area
Multi-storey extensions
If your extension will have more than one storey, you don’t need planning permission for it as long as:
- it’s located at the back of the house
- there are at least 10 metres between the extension and the boundaries of your grounds
- it isn’t higher than your house (excluding chimneys)
- it doesn’t cover more floor area than your original house does
- it doesn’t take up half the ‘curtilage’ – the grounds behind your home
- it isn’t within a conservation area
You should always check with your council’s planning department to see whether you need to apply for planning permission. Even if you don’t, there may be other approvals you’ll need to get.
For a more detailed explanation of what’s considered a permitted development when adding an extension to your house, read the Scottish Government’s Guidance on Householder Permitted Development rights publication and go to section 4.11.
Planning permission
If the extension you want to build doesn’t meet the conditions for permitted development, you have to apply for planning permission.
Read our guide on how to apply for planning permission, or contact your local council for further information.
