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Prior approval

The ‘prior approval’ process only applies to larger single-storey rear extensions.

This is defined as extending beyond the rear wall of the original house* by:

  • over four and up to eight metres for detached houses; and
  • over three and up to six metres for all other houses

If you wish to build an extension of this size, you must apply to the local authority, who will then consult the adjoining neighbours to advise them of your proposals.

If your neighbours raise any concerns or objections, the local authority will be required to determine if the proposal’s impact on the amenity of all adjoining properties is acceptable and, based on this, whether it can go ahead.

Read about how your extension may affect your neighbours1.


Prior Approval: Larger Home Extension

A householder can apply online to the local planning authority2 when they intend to build a larger single-storey rear extension, as described above.

Please read our guidance note for further information about the process3.

A planning consultant may help with the smooth running of your extension project. To find an accurate consultancy quote, explore Studio Charrette's calculators4.


Definitions

Original house

Also known as the ‘original dwellinghouse’.

This 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.

Find a Trade Professional

Use our partner directories from CIAT, FMB, RIBA, or RTPI to find an chartered architectural technologist, builder, architect or planning consultant to help with your project or development.

Find a trade professional


Useful links

Make an application Project estimating service


Planning consultancy calculator Financing your project
    1. https://www.planningportal.co.uk/permission/responsibilities/planning-permission/factors-affecting-planning-permission-your-neighbours
    2. https://www.planningportal.co.uk/planning/planning-applications
    3. https://ecab.planningportal.co.uk/uploads/1app/guidance/guidance_note-larger_home_extension.pdf
    4. https://www.planningportal.co.uk/permission/home-improvement/planning-consultancy-calculator

    The Planning Portal is delivered by PortalPlanQuest Limited which is a joint venture between TerraQuest Solutions Limited and the Department for Levelling Up, Housing & Communities. All content © 2022 Planning Portal.

    The Planning Portal is delivered by PortalPlanQuest Limited which is a joint venture between TerraQuest Solutions Limited and the Department for Levelling Up, Housing & Communities. All content © 2022 Planning Portal.