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When Can Windows and Doors Be a Permitted Development?

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In this blog, we’ll explain when windows and doors could be considered permitted development and when planning permission may be required.

Permitted Development Basics  

Windows and doors could be considered permitted development meaning planning permission is not required. However, there are some important caveats, to be aware of to avoid falling foul of the most common permitted development mistakes. Only houses have permitted development rights but not all houses have permitted development rights. Flats, maisonettes, and commercial properties always need planning permission. 

Planning Constraints  

Planning constraints such as conservation areas, listed buildings, world heritage sites, areas of outstanding natural beauty, article 4 directions or even living under a flight path may limit or remove your permitted development rights. Any previous developments even by a previous owner a long time ago may have used some, or all of your Permitted Development rights, meaning planning permission IS required. 

Planning policies are also ever-changing. Even if your windows and doors are permitted development today, the council can impose new planning constraints that remove your permitted development rights at any time in the future. This could result in a breach of planning, and risk enforcement action. If an enforcement notice is issued and retrospective planning permission is refused you would need to demolish the windows and doors and restore the property back to its original state. 

When Can Windows and Doors Be Permitted Development? 

When Can Windows and Doors Be Permitted Development? 

If your house has permitted development rights and there are no hidden constraints that removed your PD rights, your windows and doors may not need planning permission.

  • This generally applies if you replace existing units with ones matching the original style, size, and appearance, and only upgrade single glazing to double glazing when the external look remains unchanged.
  • When adding new openings, any alterations must be only “minor” and must not create privacy or overlooking issues, especially for side-facing windows.

However, even if your windows and doors meet these criteria, you may still need planning permission. 

For example, if there are hidden planning constraints or your permitted development rights have been used up by previous developments. 

It is important to note that 20% of our planning applications are retrospective and 99% of these were sure they didn’t need planning permission but got it wrong. 

 With this in mind, it’s best to check with your local planning authority or a chartered town planner before commencing work to limit your risk and expense. 

How to Find Out If You Need Planning Permission?

To find out if you need planning permission you have 2 options. 

The first option is to submit a pre-application to your council.  

This requires architectural drawings showing the property before and after the works, along with a detailed proposal explaining your plans and how they meet the relevant planning policies.  A pre-app costs up to £600 and typically takes 5 to 8 weeks for a response, though it’s not a legal determination and doesn’t guarantee approval. 
 
Alternatively, our town planners can provide a planning appraisal.   

We check the same planning policies, planning history, and planning constraints as the council but without the need for architectural drawings or a detailed proposal. The advantage of a planning appraisal is you’ll get the answers you need within a day instead of waiting weeks. 

A Lawful Development Certificate  

For anything likely to be considered Permitted Development it is always recommended to obtain a Lawful Development Certificate before commencing any works. A Lawful Development Certificate is the only way to prove that your development is Permitted Development and does not need planning permission.

It is also often required when selling or remortgaging your property, to prove to buyers or lenders that all modifications are lawful. Without planning permission or a lawful development certificate your windows and doors may not increase the value of your property. By securing a Lawful Development Certificate, you’re investing in both the future security and potential value of your property.

If you’re considering installing windows and doors and would like any help or advice contact us for a free no-obligation consultation.

When Can Windows and Doors Be Permitted Development? 

Windows and Doors Permitted Development FAQs

Can windows and doors be permitted development?

Yes, replacing windows and doors can sometimes be permitted development if the new units are similar in appearance to the existing ones and do not significantly alter the external character of the property. However, permitted development rights do not apply to every property and may be restricted by planning constraints or conditions.

When do windows and doors need planning permission?

Planning permission may be required if the works involve new openings, major changes to the size, style or position of windows and doors, alterations that affect privacy or overlooking, or changes to a property in a conservation area, listed building setting or other protected location.

Can I replace windows with double glazing under permitted development?

Replacing single glazing with double glazing may be permitted development if the external appearance remains similar to the existing windows. If the replacement changes the design, frame material, glazing pattern or character of the property, planning permission may be required.

Can I add new windows under permitted development?

New windows may be permitted development in some cases if they are minor and do not create overlooking, privacy or design issues. Side-facing windows often require particular care, especially where they could overlook neighbouring properties.

Do side-facing windows need obscure glazing?

Side-facing windows may need to be obscure glazed and non-opening below a certain height if they could affect neighbouring privacy. This is especially important where new windows are added as part of permitted development works.

Do windows and doors in conservation areas need planning permission?

Windows and doors in conservation areas, listed building settings, Article 4 areas or other protected locations are more likely to need planning permission. These areas often have stricter controls because changes to windows and doors can affect the character and appearance of the property and surrounding area.

Should I get a Lawful Development Certificate for windows and doors?

A Lawful Development Certificate can be useful if you believe your window or door works are permitted development. It provides formal confirmation from the local planning authority that the works are lawful and can help when selling, remortgaging or responding to future enforcement concerns.

What happens if my windows or doors are not permitted development?

If the works needed planning permission and were carried out without approval, the council may investigate and could take enforcement action. You may need to submit a retrospective planning application, change the design, replace the units or restore the previous appearance in serious cases.

Aaron Basi

Author Aaron Basi HEAD OF TOWN PLANNING


A versatile and resilient Chartered MRTPI Town Planner with private and public sector experience. Aaron has a deep understanding of the planning process as both the applicant and local planning authority. Whether small scale residential or large scale commercial developments his expertise ensures the best advice and robust planning applications.

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