Rear house extensions

Due to current legislation, you can build a single storey extension under permitted development rights if you are a:

  • detached house and the build will not extend further than eight metres from the original rear wall
  • terraced or semi-detached house and the build will not extend further than six metres from the original rear wall

In the above instances, you will need to notify us by submitting a prior approval application. Prior approval notifications are subject to a fee of £96.


However, if your development meets the below criteria, you will not need to notify us: 

  • a detached house extends four metres (or less) from the original rear wall
  • a terraced or semi-detached house extends three metres (or less) from the original rear wall


  • Only half the area of land around the "original house" can be covered by extensions or other buildings
  • Extensions cannot be higher than the highest part of the existing roof; or higher at the eaves than the existing eaves
  • Where the extension comes within two metres of the boundary, the height at the eaves cannot exceed three metres
  • Extension cannot be built forward of the ‘principal elevation’ or, where it fronts a highway, the ‘side elevation’
  • The work cannot include:
    • verandas, balconies or raised platforms
    • a microwave antenna (e.g. TV aerial or satellite dish)
    • a chimney, flue or soil and vent pipe
    • any alteration to the roof of the existing house.
  • On Article 2(3) designated land, the work cannot include cladding of the exterior
  • The materials used in any exterior work must be of a similar appearance to those on the exterior of the existing house

How to apply

Your application must include:

  • a description of the proposal showing:
    • how far the proposal extends beyond the original rear wall of the house
    • the maximum height of the extension
    • the height of the eaves
  • a plan showing the site and extension
  • the addresses of houses which share a boundary
  • your developer’s address and email

After your application is reviewed, we may ask for

  • recent photographs of the rear elevation of your property
  • recent photographs of the side and rear boundaries of your property
  • drawings of each elevation of the proposed extension to show dimensions and all new windows and doors to be added (including roof lights and glazed walls or roofs)

Scaled plans are not required but are recommended to make your neighbours fully aware of your proposal.