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Guide to planning permissions for windows and doors

About this guide

This guide has been created based on our experience of working within the various London boroughs, but the same logic and rules loosely apply across all of England, Scotland and Wales. It is intended for guidance only, you should always check with your local authority before making any alterations to your home.

Do I need planning permission to change windows and doors in London?

The answer to this question depends on where you live and the type of property you live in. The rules are different for each of the following four categories:
  • Houses, flats, and offices which are NOT in a conservation or listed
  • Houses which are in a conservation area and not listed
  • Flats and offices which are in a conservation area and not listed.
  • Listed buildings of all grades (houses, flats, and offices).
A brief description of rules for each category is below, please note that this is for guidance only and if you are unsure about the rules that govern your property please contact your local planning authority.

Category 1 - Houses, flats, and offices which are NOT in a conservation area or listed.

The Quick Answer: Planning permission is NOT needed for houses. Planning permission is USUALLY NOT needed for flats and offices, but this is decided at local level and is at the discretion of your local planning authority.
You do not normally need planning permission to change your windows and doors as this is considered ‘permitted development’ for houses. Flats and offices do not ‘technically’ benefit from permitted development for any changes however windows and doors are usually the exceptions, but this is at the discretion of your local planning authority. Taking Westminster as an example, if you own a flat or office which is not in a conservation area and you want to replace your old single glazed timber sash windows with new ‘like for like in appearance and material’ timber sash windows then Westminster will not require a planning application. If you wanted to replace your windows with uPVC then Westminster may ask for a planning application to discourage the use of uPVC windows in period housing. In summary, you are free to change your windows and doors without any formal permissions. It is worth noting that all replacement windows and doors are within the scope of building control regulations. This means that replacement windows or doors must comply with thermal performance and safety standards. If you choose a FENSA registered company to install your new windows or doors then the installer must legally ensure that your new windows conform to building control regulations and certify them with your local authority’s building control office.

Category 2 - Houses which are in a conservation area and are not listed.

The Quick Answer: Planning permission is NOT needed for houses to replace the windows and doors on condition that the new items are ‘like for like in materials and appearance’. Timber must be replaced with timber, and sliding sash with sliding sash.
You do not normally need planning permission to change your windows and doors if your property is a dwelling house (not a flat or office) in a conservation area on condition that they are ‘like for like in material and appearance’. This means if your outgoing windows are made of timber then your new windows must be also made of timber, and if your outgoing windows are sliding sash windows then so must the new ones be. There is one exception to this, if your property is covered by an Article 4 Direction then you will need planning permission in all instances. The effect of an Article 4 direction is that a planning application is required for developments that would otherwise not require an application for planning permission. In general planning applications for Article 4 properties are only approved when the change of windows is ‘like for like’ in both style and materials.

Category 3 - Flats and offices which are in a conservation area and not listed.

The Quick Answer: Planning permission is NOT needed for flats and offices to replace the windows and doors on condition the new items are ‘like for like in materials and appearance’. However, each local planning authority has a local policy regarding flats and offices and they may insist on a planning application.
Planning law for flats, maisonettes, and offices differs to that which covers houses as they do NOT technically benefit from permitted development and therefore you need planning permission for any changes. However, windows and doors are usually the exceptions to this, but again this depends on your individual local authority. Local authority policy and interpretation of the rules covering changing windows in flats varies from council to council and you are advised to contact your local planning authority for advice before starting work. The majority of local authorities in London and the rest of England have the following policy:
If your property is a flat or an office in a conservation area then you do NOT need to apply for planning permission to change your windows and doors on condition the new items are ‘like for like in material and appearance’. This means if your outgoing windows are made of timber then your new windows must be also made of timber, and if your outgoing windows are sliding sash windows then so must the new ones be. There is one exception, if your property is covered by an Article 4 Direction then you will need planning permission in all instances. An Article 4 direction is a special planning regulation adopted by a local planning authority. It removes permitted development rights from whatever is specified in the Article 4 direction.

Category 4 - Listed buildings of all grades, both houses, flats and offices.

The Quick Answer: Yes, planning is needed in every instance.
If you live in a listed building you will need planning permission and listed building consent to change your windows and doors. The rules around replacing windows and doors in listed buildings are strict and for good reason, as they are designed to protect our architectural heritage. In general, it is very difficult to get planning permission, in fact, it’s easier to list the reasons why planning can be refused rather than granted:
  • You will not get permission to change your windows unless they are beyond economical repair, for example, if the sash box is completely rotten. Reasons such as “they are old, single glazed, or they let out loads of heat” are not valid reasons. The planners will want you to repair and maintain historical windows so you must demonstrate that this is not possible.
  • You will not get permission to change from single to double glazing. However, special heritage ‘slimline’ double glazing is usually acceptable in Grade 2 buildings. With Grade 2* and Grade 1 properties is very difficult to get permission to use slimline glazing, usually only single glazing is acceptable. In addition, your conservation officer may insist on traditional ‘hand-drawn’ glazing, this glass is handmade and has ripples and imperfections in it.
  • You will not be allowed to change materials, such as timber to uPVC or the appearance of the windows or doors.
In general planning permission to replace your windows and doors is usually only granted in listed buildings when the existing windows and doors are beyond economical repair, the new items have heritage appropriate glazing, and the new items are identical in appearance.

Can I use double glazing in my period property which is NOT listed?

You are permitted to use double glazing in a period property without planning permission, regardless of whether you live in a conservation area or not. However you will need to apply for planning permission if you are in a conservation area with an Article 4 Direction. The decision on glazing is with your local conservation officer who may want to maintain original details (such as single-glazing) and compromise energy efficiency in order to preserve character. Therefore, it is advisable to meet the conservation officer prior to a full application to discuss all the options available.

Can I use double glazing in my period property which is listed?

This depends on a number of factors and is the decision of your local planning authority, Grade 1 and 2* listed buildings are not normally allowed the use of double glazing of any type. Grade 2 listed buildings are sometimes permitted to use 16-18mm conservation area double glazing, but the preference is usually for the use of heritage appropriate glazing such as slimline 12mm double glazing or single glazing. You may get permission to use 18-16mm conservation area double glazing on windows which are hidden from public view, such as the back elevation of a house. Ultimately you are at the mercy of your local conservation officer on which type they want to use, therefore, it is advisable to meet the conservation officer prior to a full application to discuss their preferences.

Still unsure?

We’re very proud in being a timber only company, helping to preserve London’s architectural heritage. If you have any questions about your options we are happy to help, over the phone on 020 3198 4472 or via email hello@sashed.com.
A grade 2 listed building with timber sash windows

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