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.

You may wish to make loft alterations to enhance the storage facilities available or to increase the living space of the home. Converting the loft of a house is considered to be permitted development (not requiring an application for planning permission) subject to certain limits and conditions.

Remember, building regulations approval is required to convert a loft or attic into a liveable space.

Find out about loft conversions

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There are different rules for flats and maisonettes regarding loft conversions. Read guidance for converting the loft of a top floor flat.

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Merging two flats into one, commonly known as amalgamation is likely to require planning permission as it will impact the local planning authorities housing supply. The council’s views on this will vary from council to council. It is recommended that you contact your local planning authority to understand their position.

If you do not need to apply for planning permission then you can apply for a lawful development certificate to prove that the change is lawful.

Building regulations will be required if there are physical works taking place as part of the amalgamation, this may include removing walls or changing electrics. Visit the relevant common projects on our site for more information.

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The addition of a new external doorway will often fall under permitted development rights, meaning an application for planning permission is not required. This applies where the new doors are of similar appearance to those used elsewhere on the original building.

Permission may be required if your property is listed, you live in a conservation area oran Article 4 direction is in place. In these circumstances it is best to contact your local planning authority for more advice.

New external doorways which create a new or widened opening must comply with building regulations. A new structural opening will require a building regulations application.

The installation of a new door can be completed by a 'competent person' to ensure building regulation requirements are met. For more information on the competent person scheme and to find a registered person, visit the GOV.uk website.

A wall is a 'party wall' if it stands astride the boundary of land belonging to two (or more) different owners, for example the wall separating two semi-detached properties.

Some kinds of work carried out to a property may not be controlled by the building regulations, but may be work which is covered by the Party Wall etc. Act 1996. This is a separate piece of legislation with different requirements to the building regulations.

To find out more about party walls, visit Planning Portal.

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