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I’m replacing a window, do I need planning permission or building control approval increase its size?

Increasing the size of a window will often fall under permitted development rights, meaning an application for planning permission is not required to make the change, provided limits and conditions are met.

Any new window must be of similar appearance to the original which you are replacing.

Permitted development rights do not apply to flats. To increase the size of a window in a flat or maisonette you will require planning permission.

 If you live in a listed building, you will require listed building consent for any major changes.

Where the work has as significant impact on the external appearance of the house, especially on the principal elevation, planning permission may be required.

Building control approval will likely be required where the change impacts the structure of a building, this primarily occurs when an opening Is widened. When altering walls you may want to consult a structural engineer.

Building control will also consider energy efficiency, glazing, ventilation and fire safety.

Common Questions

How long does planning permission last?

By law, any planning permission granted expires after a certain period. Generally, unless your permission says otherwise, you have three years from the date it's granted to begin the development. If you haven't started work by then, you will probably need to reapply.

What happens if I build without permission?

If you do not seek planning permission, build without it when it applies, or do not meet specified conditions of a planning permission, this is known as a planning breach.

Your local planning authority can serve an enforcement notice on you when they consider you have broken planning rules. You may be given the opportunity to apply retrospectively, or be required to remove a building or structure, or alter it to make it acceptable.

Read about your responsibilities.

Do I need planning permission to build a basement underground?

Creating a new basement will usually require planning permission, particularly if it affects the external appearance of the property. For example, installing a lightwell to bring natural light into the basement may be subject to stricter design rules if it is visible from the street, especially at the front of the property, compared to those at the rear or side.

Because basement construction involves significant excavation and structural work, permission is often necessary. It’s recommended that you consult your local planning authority early on to understand what is likely to be considered acceptable before submitting a planning application. Building regulations will also apply to a new or conversion of a basement.

Read further guidance on basements.

Do I need permission to demolish an old lean-to and rebuild to the same measurements?

Demolishing and building a new lean-to will still have comply with planning requirements.

If you live in a conservation area or listed building you may require approval for the demolition.

Whether a lean-to requires planning permission will depend on what the lean-to is used for, it may be an extension, pergola, carport, conservatory or gazebo.

In some cases a building a lean-to will be classified as permitted development, meaning an application for planning permission is not required provided specified limits and conditions are met. If these are exceeded, then you must apply for planning permission.

Permitted development rules vary based on the type of work you are completing, visit our interactive house mini guides for details on the specific rules.

If you live in a listed building, you will need listed building consent for any significant changes.

How can I find out the progress of my planning application

Once you submit your application it will be considered by the local planning authority. The Planning Portal does not have access to the application once it is submitted.

You will need to contact your local planning authority to check on the progress of any submitted application. Many authorities now let you track the progress of applications on their own council websites.

Your local authority’s contact details and website address can be found by using our local authority search.

Search for the contact details of your local authority.

Read about the decision-making process.

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