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Do I Need Planning Permission for a double storey extension?

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Do I Need Planning Permission for a two storey extension?

Planning permission is usually required for a two-storey/double-storey side extension or rear extension, but it depends on the location, type of property and size of the extension. If the property is a flat, or if the property is listed, planning permission will always be required. If the rear extension is the same depth as the ground floor rear extension then planning permission might not be required.

Whether you need planning permission for a two-storey extension to your house depends on various factors, including your local planning authority's regulations and the specifics of your extension. Generally, you might need planning permission, but there are circumstances under which the extension could be considered permitted development.


Permitted Development Rights for two storey rear extensions

Permitted Development Rights

Permitted development rights allow certain types of work to be carried out without needing planning permission, provided specific conditions are met:

  1. Size and Scale:

    • The extension must not extend more than 3 metres from the original rear wall for semi-detached or terraced houses, or 4 metres for detached houses.
    • The overall height of the extension must not exceed the height of the highest part of the existing roof or be higher than 7 metres from ground level.
  2. Location:

    • The extension must be at least 7 metres away from the rear boundary.
    • It must not extend beyond the front or side elevation of the house that faces a highway.
  3. Roof Design:

    • The roof pitch of the new extension should match the existing house.
  4. Materials:

    • The materials used in the extension must be similar in appearance to those used in the existing house.
  5. Restrictions:

    • No balconies, verandas, or raised platforms are allowed without planning permission.
  6. Designated Areas:

    • In certain areas, such as conservation areas additional restrictions may apply, or permitted development rights might be more limited.
  7. For further information on what is considered permitted development, please see here: https://www.4dplanning.com/what-is-permitted-development-



Planning Permission for double storey extensions

Planning Permission

If your extension does not comply with permitted development criteria, you will need to apply for planning permission. Considerations include:

  • Neighbour Impact: Effects on neighbours, such as overlooking, overshadowing, and privacy loss.
  • Design and Appearance: How the extension fits with the existing house and the surrounding area.
  • Environmental Considerations: Any potential environmental impacts or effects on heritage sites.


If you are unsure about the permitted development rights or if you require assistance with your proposed two storey extension, 4D Planning are here to assist you.

Please give us a call or email us for a consultation: enquiries@4dplanning.com

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