roomoutsideuk Room Outside Admin
20th October, 2021

Permitted Development Rights: All you need to know about adding a conservatory

One of the biggest things that our customers want information on is whether they can build their conservatory or orangery under permitted development, therefore taking the hassle and cost out of having to gain planning permission to build their glass structure. Like with most things it depends on several factors, but in many cases permitted development rights will be enough for a small-medium size structure.

Here is a quick guide to permitted development rights for conservatories and orangeries:

Permitted Development Rights

How big can a conservatory be without getting planning permission?


A conservatory, orangery, glass or traditional extension can be up to 6 metres length wise for a terraced or semi-detached house without most homeowners needing to gain planning permission.  For detached houses you are allowed to build up to 8 metres from your home under Permitted Development. The amount you can extend your home by is a total for your property rather than per extension, so if your home has been extended before, this area will reduce the size you can use for your glass extension.

What is Permitted Development?

Permitted development is a set of rules which allow you to make improvements to your home including adding an extension without having to gain planning permission.  If your new structure falls within the criteria set out in the rules for PD, if your project would exceed this you would need to apply for planning permission. There have been quite a few changes over the last 12-18 months (2020/21) to allow for more flexibility including adding a fast-track route for two-storey extensions and changing the rules on changing a commercial property into a residential home. PD has made it much easier for you to add a glass extension to your home for most people, but there are some exceptions so you would need to take advice from a reputable company to be sure that your home and extension comply with the PD criteria.

What work does Permitted Development include?

Within specified criteria and limitations, PD may allow you to:

  • Build a small single-storey rear or side extension
  • Build a double-storey rear or side extension
  • Add a small porch
  • Knock down internal walls
  • Convert your garage, basement, or loft
  • Add a balcony
  • Add in rooflights or dormer windows

If you have a listed property or are in an area of outstanding natural beauty, you may find that your Permitted Development rights are restricted further and would need to gain planning permission. These rights also don’t apply to flats and maisonettes, due to the nature of these buildings, any work done may impact the property around them and so planning would be required so that the council can assess how the work would affect your neighbours. You must also of course ensure any building work complies with Building Regulations even if your structure falls under the scope of PD.

Using permitted development rights for conservatories and glass extensions

While the premise of using PD to add your glass extension may sound ideal, there are some things that you need to consider when using this method.  PD applies to the original building so when you purchase a home that has already had some extension, this would already count as part of your extension allowance under PD.  So, when sizing up your plans, make sure you factor in any past work done on the house. Larger extensions are likely to require planning permission, but the planning authority will consider what would be permissible under PD and how much larger or higher the overage is to see whether it is acceptable.

Where to find out more

If you are thinking about adding your glass extension under Permitted Development, you can find lots more information on the rules on the Planning Portal.  It is also advisable that you double-check with your local authority prior to building to ensure that you are within the regulation. If you go ahead assuming that PD covers your extension but later it is found not to, you will need to retrospectively apply for planning permission and if not granted could result in enforcement action including removing the structure, so it is important that this is all checked. Our team of experts also have over 5 decades of experience in building glass extensions and has a wealth of knowledge on planning rules and Permitted Development, so we will be happy to discuss your proposed project with you and answer any questions you may have.  If we are not able to answer all your questions, we can refer you to our contacts at your local authority to get sound advice.

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