Depending on whether you’re planning to improve your existing house or carry out significant works to the one you intend to buy, it pays to understand the scope of the available Permitted Development rights.

Permitted development rights are there to allow householders to improve and extend their homes without applying for planning permission.

They are typically granted as General Development Planning Orders (GDPOs), which apply separately to EnglandWalesScotland and Northern Ireland. They provide implied planning consent to carry out certain classes of development in your home.

Permitted development rights will allow you to extend your house without the need to go through an application for planning permission, but only if certain specific conditions and limitations are met.

You can, of course, exceed these, but this would mean you would be likely to need to go through an application for householder planning permission.

If the work you are planning to undertake would add over 100 square metres of floor space to your home, it may also be liable for a charge under the Community Infrastructure Levy.

Key Rules

All Extensions

  • 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.
  • The 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.
  • The materials used in any exterior work must be of a similar appearance to those on the exterior of the existing house.


Side Extensions

Where it would extend beyond the ‘side elevation’ of the original house, the extension:

  • Cannot exceed four metres in height.
  • Can only be a single storey.
  • Can only be up-to half the width of the original house.


Single Storey Extensions

  • Single-storey rear extensions cannot extend beyond the rear wall of the original house* by more than four metres if a detached house; or more than three metres for any other house.
  • Where not on Article 2(3) designated land* or a Site of Special Scientific Interest; and subject to ‘prior approval’, the limit for single-storey rear extensions is increased to eight metres if a detached house; or six metres for any other house.
    This requires that the relevant Local Planning Authority is informed of the proposed work via a prior approval application.
  • Single-storey rear extensions cannot exceed four metres in height.


Extensions of more than one storey

  • Extensions of more than one storey must not extend beyond the rear wall of the original house* by more than three metres or be within seven metres of any boundary* opposite the rear wall of the house.
  • Roof pitch must match the existing house as far as practicable (note that this also applies to any upper storey built on an existing extension).
  • Any upper-floor window located in a ‘side elevation’ must be obscure-glazed; and non-opening (unless the openable part is more than 1.7 metres above the floor).

All side extensions of more than one storey will require householder planning permission.



The permitted development allowances described here only apply to house, they do not apply to the following:

  • Flats and maisonettes 
  • Converted houses or houses that have already been created through the permitted development rights to change of use 
  • Areas where there may be an existing planning condition