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What size extension can I build without planning permission?

In many circumstances, rules known as ‘permitted development’ rights allow you to extend a house without needing to apply for planning permission, providing specific limitations and conditions are met. If you want to exceed these limits and conditions, then it is likely that an application for householder planning permission will be required.

You can find information about the limits and conditions, prior approval and the building regulations on the Planning Portal by using the links below.  

Read about planning permission for extensions

Read about prior approval for larger single storey extensions

Find out about building regulations for an extension

Common Questions

What happens if I build without planning permission?

If you carry out development without the necessary planning permission, and it doesn’t fall within permitted development rights, you may be in breach of the planning rules. In such cases, you will usually need to submit a retrospective planning application to seek approval for the work already completed or started. However, there is no guarantee that permission will be granted.  

Learn more about planning breaches on Planning Portal  

Can I install patio doors to the rear of my house where there is currently a single external door?

Installing patio doors at the rear of your house is likely to fall under permitted development rights, meaning an application for planning permission is not required, provided certain limits and conditions are met.

The doors should be of similar appearance to those previously used, if they are not then generally planning permission will be required.

If you live in a listed building, you will need listed building consent for any significant works.
If you live in a designated area such as a conservation area or national park, then additional restrictions may be in place.

If you are unsure whether the work falls within permitted development rights you can check with your local planning authority or submit a lawful development certificate to prove the change is lawful and prevent any future enforcement action.

Can I build a two-storey extension without planning permission?

Two storey rear extensions are considered to be permitted development, meaning they do not require an application for planning permission provided certain limits and conditions are met. If these limits are exceeded then you will need to apply for planning permission from the local planning authority.

Houses on designated land such as national parks or conservation areas are excluded from the permitted development rights and will require an application for planning permission.

To fall within permitted development rights, the extension should be no higher than the existing house, and where it is within two metres of a boundary, the eaves should be no higher than three metres. 

Any double storey extension to the side or front of the house will require planning permission. You can view the full limits and conditions on our Two-storey extension Mini Guide.

If you live in a listed building you will require listed building consent for any major works to the property.

What permissions do I need to build a dropped kerb?

A dropped kerb is a sloping point in the pavement to provide access by vehicle to a property. Dropped kerbs aren’t usually a planning matter although it is recommended that you contact your local authority to find out if planning permission is required, and you will need to make a specific dropped kerb application for a domestic vehicle crossing licence to your local authority.

Work to create a dropped kerb must be carried out by a New Roads and Street Works Act accredited contractor.

Read more about dropped kerbs

Do I need planning permission to render my house?

Rendering or cladding the exterior walls of your house may fall under permitted development rights, meaning an application for planning permission is not required provided you meet certain limits and requirements set out in legislation.

If you live in a listed building, you will need listed building consent for any significant works whether internal or external.

If you live in a Conservation Area, a National Park, an Area of Outstanding Natural Beauty or the Broads, you will need to apply for planning permission before cladding the outside of your house with stone, artificial stone, pebble dash, render, timber, plastic or tiles.

Outside these areas, cladding may be carried out without having to first apply for planning permission provided the materials are of a similar appearance to those used in the construction of the house.

If the new materials will not have a similar appearance to those previously used you will be required to submit an application for planning permission.

Read more about change to external walls on our common project.

Replacing existing render

Replacing existing render on the outside of your house with render of a similar appearance will not require planning permission as it is considered permitted development.

If you are changing the external appearance of the house or in a protected area such as a conservation area, then planning permission will be required. The external appearance of the house is likely to be changed when you are changing the type or colour of the render.

If the building is listed, then you will need listed building consent.

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