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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
The UK Government provide access to public land records, allowing you to check certain restrictions on land. You can use the online tool to check whether your land is in a conservation area.
VisitGOV.UK and use the planning data map.
(This map covers planning data for England).
If you are unsure you should contact your local planning authority.
Yes, but you will need to obtain planning permission. Converting a detached garage into a self-contained living space, such as annexe, studio flat, or retail unit, represents a material change of use, particularly if it will function independently from the main house. This is because the garage would no longer be used in connection with the main dwelling and would effectively become a separate residential unit.
There are different planning fees for England and Wales, and many different application types depending on the work being carried out.
You can use the Planning Portal's fee calculator to work out fees for different kinds of proposal.
Use the fee calculator (England)
Use the fee calculator (Wales)
While every effort has been taken to ensure that the fee has been calculated correctly, the determination of whether a planning fee is correct is the responsibility of the relevant local planning authority, who will check the fee is correct when the application is submitted and validated.
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.
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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