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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Widening or creating a new external doorway will likely fall under permitted development rights, meaning an application for planning permission is not required provided you meet limits and conditions set out in legislation. If the change is on the side or rear of the building it is more likely to comply with planning regulations.

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

New external doorways which create a new or widened opening must comply with building regulations as they may impact the structure of a building.

Read more on our doors and windows common project.

In many cases, you can build a porch without planning permission under permitted development rights, provided certain criteria are met. To qualify as permitted development, your proposed porch must:

• Not exceed three square metres in external ground area

• Be no taller than three metres in height

• Be located at least two metres away from any boundary with a highway

Read more about porches on Planning Portal

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Permitted development rights allow certain types of work to be carried out without the need to apply for planning permission. It typically covers things like small extensions, loft conversions and outbuildings, provided they meet specific size and location limits. These rights can vary or be removed in areas like conservation zones and by Article 4’s, so it’s best to check before proceeding.  

Read about permitted development and Article 4 directions on Planning Portal

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Planning permission is not normally required to turn two properties into one by knocking through a party wall provided the changes are internal and do not impact the external appearance of the property.

You should check with your local planning authority that they agree, and there are not any previous planning changes or conditions which may have an impact.

Additional permissions may be required depending on the building’s history and their location. If the building is listed, an application for listed building consent will be required before any major changes are made to the dwellings.

The work will have to comply with building regulations, the focus will be on structural work and safety.

‍Read more about how building regulations apply to internal walls.