New Planning Permission: Rules 2013

Single Storey Rear Extension Single Storey Rear Extension

NOTE:   Legislation allowing larger single-storey rear extensions to be built under permitted development rules has been laid before Parliament and will come into force on 30 May 2013 and last for 3 years. The new size limits will be subject to a neighbour consultation scheme.

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 extension must not extend beyond the rear wall of the original house* by more than six metres if an attached house or by eight metres if a detached house.
  • Maximum height of a single-storey rear extension of four metres.
  • Extensions of more than one storey must not extend beyond the rear wall of the original house* by more than three metres.
  • Maximum eaves height of an extension within two metres of the boundary of three metres.
  • Maximum eaves and ridge height of extension no higher than existing house.
  • Side extensions to be single storey with maximum height of four metres and width no more than half that of the original house.
  • Two-storey extensions no closer than seven metres 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 designated land** no permitted development for rear extensions of more than one storey.
  • On designated land no cladding of the exterior.
  • On designated land no side extensions.

Please note:   the permitted development allowances described here apply to houses not flats, maisonettes or other buildings.

Please be aware that if your development is over 100 sqm, it may be liable for a charge under the Community Infrastructure Levy.

*   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.

**   Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.

Most extensions of properties will however still require approval under the Building Regulations.