Extending Your Home Without Planning Permission

When it comes to home extensions, planning permission can be a minefield. Fortunately, you may be covered by ‘permitted development’ rights, which allow you to extend a house without needing to apply for planning permission, as long as specific limitations and conditions are met.

Permitted development rights apply to houses only so do not cover flats, maisonettes, converted houses (e.g. barn conversions) or other buildings.

Extensions that always require planning permission

There are a number of house extensions that are not covered by permitted development rights and do require planning permission:

  • All side extensions of more than one storey.
  • All front extensions.
  • On Article 2(3) designated land, all rear extensions of more than one storey and all side extensions (including single storey).

The following rules apply for all house extensions:

  • Only half the area of land around the “original house” (as it was first built) can be covered by extensions or other buildings.
  • Extensions cannot be higher than the highest part of the existing roof.
  • Where the extension comes within two metres of the enclosed boundary of the house, the height at the eaves cannot exceed three metres.
  • Extensions cannot be built forward of the ‘principal elevation’, the elevation which fronts a highway.
  • The materials used in any exterior work must be of a similar appearance to those on the exterior of the existing house.
  • On Article 2(3) designated land (including Conservation Areas and Areas of Outstanding Natural Beauty) the work cannot include cladding of the exterior.

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.

Front extensions are not allowed under permitted development rights, the rights only allow side and rear house extensions. Side extensions:

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

For single storey rear extensions, the extension:

  • Cannot extend beyond the rear wall of the original house by more than four metres if a detached house; or three metres for any other house.
  • Single-storey rear extensions cannot exceed four metres in height.

For two storey rear extensions, the extension:

  • 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.
  • Any upper-floor window located in a ‘side elevation’ must be obscure-glazed, and non-opening.

Prior Approval Extensions

For houses not on designated land and subject to ‘prior approval’, the limit for single-storey rear extensions is increased to eight metres for a detached house; or six metres for any other house.

This process requires that the relevant Local Planning Authority is informed of the proposed work via a prior approval application but is not strictly a planning permission process.

If you want to exceed the permitted development right criteria or build an extension as listed above it is still possible, however an application for householder planning permission will be required.

If you have property to extend and would like to explore the options available, please contact the Planning and Architecture Team on 01789 387880 or visit the Planning and Architecture pages of our website.