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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
If you do not seek planning permission, build without it when it applies, or do not meet specified conditions of a planning permission, this is known as a planning breach.
Your local planning authority can serve an enforcement notice on you when they consider you have broken planning rules. You may be given the opportunity to apply retrospectively, or be required to remove a building or structure, or alter it to make it acceptable.
It is likely that you will require planning permission to extend an existing front porch to add a toilet.
Adding a porch falls within permitted development rights meaning an application for planning permission is not required provided specified limits and conditions are met. However, to fall under permitted development rights for a porch, the total ground area must not exceed three square metres. This is unlikely to be enough room to fit toilet and the required additional components.
Read the full rules for porches under permitted development on our mini guides.
If your porch exceeds these limits, it will be classified as an extension. These can be permitted development but come with a different set of rules.
Extensions are not permitted development if they are built forward of the ‘principal elevation’ of the house. As such, you will be required to submit an application for planning permission to your local planning authority.
If you live in a listed building, you will need listed building consent for any significant changes.
You will often not require planning permission to fit a log burner. If you are adding a new external flue or chimney then different rules will apply.
If you live in a listed building you will require listed building consent.
The installation of a log burner must comply with building regulations. It is recommended that you use a HETAS-registered installer who can certify the work. Visit the HETAS website to search for an installer.
Read more information around fitting an external flue or chimney in our common projects section.
When you, or an agent acting on your behalf, have submitted a planning application, the local authority will firstly check the application to check if it’s complete. This validation process allows the authority to ensure everything that is required to decide an application has been received and provided correctly. They will contact you if they require any further information from you.
After the application has been validated, the determination process begins and takes up to 8 weeks for smaller applications, or up to 13 weeks for larger applications. The authority should be able to give you an idea about the likely timetable. The local authority will contact you with their decision.
Read more about the decision-making process for planning applications.
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.
