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Do I need planning permission or building control approval to merge two flats into one?
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.
Common Questions
Yes, but this type of conversion will require full planning permission. This is because you’d be changing the use of the ground floor from residential to commercial (typically to a use class such as E), while the upper floor would remain as a residential flat (Class C3). The change of use triggers the need for planning approval.
Find out more about change of use
Foundations are required to carry and distribute the load of the building safely. Therefore, all buildings should have adequate foundations. The factors that need to be considered when designing a foundation are:
- Type of soil
- Adjacent structures
- Trees
- Drains and sewers
- Size and construction of the new building
- Ground condition
- Landfill sites
It is advisable to contact a structural engineer or speak to a building control body about plans for new foundations.
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.
Fitting, altering or replacing an external flue, chimney, or soil and vent pipe is normally considered to be permitted development, not requiring an application for planning permission, providing certain conditions are met.
Read about the conditions which must be met to comply with permitted development rules.
Building regulations apply to installing a flue, and installation should be carried out by a suitably qualified installer.
Read about building regulations for flue installation.
Replacing the window within a bay window is treated the same as any other window. Meaning that the replacement of windows which have a similar appearance to those previously used would not require an application for planning permission.
Repairs, maintenance and minor improvements will also not require an application.
If you live in a listed building or a designated area then different rules may apply.
For more details on replacing windows, visit our common projects section.
