Without planning permission in the UK, you can typically extend your house as follows under permitted development rights:
- For single-storey rear extensions, you can extend up to 6 meters for terraced or semi-detached houses, and up to 8 meters for detached houses without needing planning permission.
- Extensions must not exceed more than half the width of the original house.
- The extension's height must not exceed 4 meters.
- Side or front extensions must be closer to the property than a public highway.
- The extension roof height must not exceed the height of the original house, and eaves must not exceed 2 meters in height if within 3 meters of the boundary.
- Extensions in conservation areas or other restricted zones might have additional limits.
These limits are subject to conditions and local regulations, so it is advisable to check with local planning authorities for any restrictions or the need for a prior notification under the Neighbour Consultation Scheme.
