What Planning Permission Do You Need For A New Conservatory?

If early indications are anything to go by, conservatory sales at TWC are set to remain strong in 2019 as we’ve already had numerous orders placed for this stunning style of extension since the turn of the year.

Ultraroof Conservatory

In any initial meeting we have with a customer interested in buying a conservatory we advise of the possibility of the extension needing planning permission prior to us building it on their behalf. It would be irresponsible of us not to as contravening planning laws innocently or knowingly can leave a householder in all sorts of trouble – they could be ordered to modify the design to bring it in line with the rules or told to completely knock the structure down.

To save people from such financial and personal embarrassment, we let them know of the rules relating to planning permission for conservatories.

The first point to make is that a single-storey rear extension (conservatory) considered to be a permitted development DOES NOT require planning permission. A conservatory is categorised as a permitted development when these limits and conditions are met:

  • No more than half the area of land around the “original house”* would be covered by additions or other buildings.
  • No extension forward of the principal elevation or side elevation fronting a highway.
  • No extension to be higher than the highest part of the roof.
  • Single-storey rear extension must not extend beyond the rear wall of the original house* by more than three metres if an attached house or by four metres if a detached house.
  • In addition, outside Article 2(3) designated land* and Sites of Special Scientific Interest the limit is increased to 6m if an attached house and 8m if a detached house until 30 May 2019.
  • These increased limits (between 3m and 6m and between 4m and 8m respectively) are subject to the prior notification of the proposal to the Local Planning Authority and the implementation of a neighbour consultation scheme. If objections are received, the proposal might not be allowed.
  • Maximum height of a single-storey rear extension of four metres.
  • Extensions of more than one storey must not extend beyond the rear wall of the original house* by more than three metres.
  • Maximum eaves height of an extension within two metres of the boundary of three metres.
  • Maximum eaves and ridge height of extension no higher than existing house.
  • Side extensions to be single storey with maximum height of four metres and width no more than half that of the original house.
  • Two-storey extensions no closer than seven metres to rear boundary.
  • Roof pitch of extensions higher than one storey to match existing house.
  • Materials to be similar in appearance to the existing house.
  • No verandas, balconies or raised platforms.
  • Upper-floor, side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor.
  • On designated land* no permitted development for rear extensions of more than one storey.
  • On designated land no cladding of the exterior.
  • On designated land no side extensions.

* The term “original house” 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.

* Designated land includes conservation areas, national parks and the Broads, Areas of Outstanding Natural Beauty, and World Heritage Sites.

When a conservatory falls short of any of these limits and conditions and you still want it to be constructed, a planning application will need to be submitted to your local authority. You can do this via the Planning Portal website.

They will assess the application and judge whether they’re happy or not for the extension to proceed, giving their reasoning behind rejecting the plans when this is the case.

A more detailed guide to Planning Permission has been drafted by TWC and can be downloaded for FREE on our Helpful Guides page.





Everyone is welcome to come in and browse around our Swindon or Oxford showroom, where our friendly sales team will be pleased to help with any questions you may have.


Want to speak with an Advisor? Give us a call on 01793 781413

Our friendly team will be pleased to help with any questions you may have.

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