A Guide to Permitted Development

Sep 18

Permitted development rights make it easier to extend and create new homes without the time and expense involved in applying for planning permission.

Permitted Development Rights for House Extensions

So long as certain conditions are met, many home extensions will fall under permitted development. These conditions are outlined below:

The following criteria must be met for single-storey extension to fall under permitted development:

Extensions can’t cover more than half the area of land around the original house*
No extension forward of the principal elevation or side-elevation fronting a highway
Materials to be similar in appearance to original house
Side extensions must be single storey
Width of side extension must not be greater than half that of the original house
Maximum eaves and ridge height no higher than existing house
If within 2m of a boundary, maximum eves height of 3m
Maximum height of 4m
For a single storey rear extension, it must not extend beyond rear wall of original house by more than 4m if a detached house; or more than 3m for any other house

The following criteria must be met for two-storey extension to fall under permitted development:

Extensions can’t cover more than half the area of land around the original house*
Maximum eaves and ridge height no higher than existing house
If within 2m of a boundary, maximum eaves height of 3m
Extensions or more than one storey must not extend beyond the rear of the original house by more than 3m, or be within 7m of any boundary opposite the rear wall of the house
Roof pitch to match that of existing house as far as possible
Materials to be similar in appearance to original house
Upper floor windows in a side elevation must be obscured glazing and non-opening unless the openable part is more than 1.7m above floor level
Balconies and verandas are not permitted development

*Original house - the house as it was first built or as it stood on 1 July 1948

Visit the Planning Portal for more information