An extension or addition to your house is considered to be permitted development, not requiring an application for planning permission, subject to the following limits and conditions:
- no more than half the area of land around the “original house” would be covered by additions or other buildings.
- no extension forward of the principal elevation or side elevation fronting a highway.
- no extension to be higher than the highest part of the roof.
- single-storey rear extensions must not extend beyond the rear wall of the original house* by more than eight meters if a detached house, or more than six meters for any other house.
If the house is in Article 2(3) designated land* or a Site of Special Scientific Interest, this limit is reduced to four meters if a detached house; or three meters for any other house.
These limits are now permanent and subject to the neighbour consultation scheme .
This requires that the relevant Local Planning Authority is informed of the proposed work via a prior approval application.
Maximum height of a single-storey rear extension of four meters.
Extensions of more than one storey must not extend beyond the rear wall of the original house* by more
than three meters.
Maximum eaves height of an extension within two meters of the boundary of three meters.
Maximum eaves and ridge height of extension no higher than existing house.
Side extensions to be single storey with maximum height of four meters and width no more than half that of
the original house.
Two-storey extensions no closer than seven meters to rear boundary.
Roof pitch of extensions higher than one storey to match existing house.
Materials to be similar in appearance to the existing house.
No verandas, balconies or raised platforms.
Upper-floor, side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor.
On Article 2(3) designated land* no permitted development for rear extensions of more than one storey.
On Article 2(3) designated land* no cladding of the exterior.
On Article 2(3) designated land* no side extensions.
* The term "original house" means the house as it was first built or as it stood on 1 July 1948 (if it was built
before that date). Although you may not have built an extension to the house, a previous owner may have
done so.
* Article 2(3) designated land is land within:
a conservation area; or
an area of outstanding natural beauty; or
an area specified by the Secretary of State for the purposes of enhancement and protection of the natural
beauty and amenity of the countryside; or
the Broads; or
a National Park; or
a World Heritage Site
For more information please visit:
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/830643/19
0910_Tech_Guide_for_publishing.pdf
