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Do I need planning permission to build 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.
Common Questions
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.
Bricking up or infilling an existing window is classified as permitted development, meaning an application for planning permission is not required to complete the works. You will need to ensure that any materials used are of a similar appearance to the existing exterior of the house.
If you live in a listed building, then you will require planning permission and listed building consent for the change. In this instance it is best practice to talk to your local planning authority first.
If you plan to put up a small, detached building like a garden shed, garden room, garden office, annexe or summerhouse (all classed as outbuildings), building regulations generally won’t apply if the building has a floor area under 15 square metres and does not include any sleeping accommodation.
For buildings with a floor area between 15 and 30 square metres, building regulations approval is usually not needed - as long as the building does not include sleeping accommodation and either:
- it is at least one metre away from any boundary, or
- it is built mainly from non-combustible materials.
Read more about the building regulations that apply to outbuildings.
Don't forget to check the permitted development rights for outbuildings.
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.
A council’s planning department, known as the local planning authority (LPA), is the local government body responsible for managing and overseeing the planning system in a specific area.
You can use the search tool on Planning Portal to find the contact details for any local planning authority in England and Wales.
