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.

Read further guidance on basements.

Common Questions

Where can I find a list of Use Classes for change of use?

Land and buildings are categorised by their type and purpose through a system known as ‘use classes’. A 'Change of use' can be within the same Use Class or from one Use Class to another.

You can find a full list of use classes and change of use scenarios related to planning on the Planning Portal website.

Read more about use classes

Do I need permission to create an opening for a new window?

Inserting new windows which look similar to those previously used in the house will often not require planning permission. Some rules apply to new additions, for example if they are on an upper-floor side elevation they must be obscure glazed and non-opening or more than 1.7 metres above the floor.

Installing a new bay window on the front elevation would require planning permission as it is classed as a forward extension.

If you live in a listed building or conservation area you should contact your local planning authority.

Any new openings will have to comply with building regulations, this may impact thermal heat loss, structure, ventilation and fire safety.

You can use a member of a competent person scheme to complete any work, this will ensure that the work is completed in-line with regulations.

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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.

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Do I need planning permission or building control approval to install a new external door into my house?

The addition of a new external doorway will often fall under permitted development rights, meaning an application for planning permission is not required. This applies where the new doors are of similar appearance to those used elsewhere on the original building.

Permission may be required if your property is listed, you live in a conservation area oran Article 4 direction is in place. In these circumstances it is best to contact your local planning authority for more advice.

New external doorways which create a new or widened opening must comply with building regulations. A new structural opening will require a building regulations application.

The installation of a new door can be completed by a 'competent person' to ensure building regulation requirements are met. For more information on the competent person scheme and to find a registered person, visit the GOV.uk website.

Do I need planning permission or building control approval to change a bathroom to an accessible wetroom for disabled access?

Planning permission is not required for internal changes such as changing a bathroom to an accessible wetroom, however, if you live in a listed building, you will have to apply for listed building consent for any significant works, whether internal or external.

Building regulations approval will likely be required for changes to a make a bathroom accessible, specifically when the change will impact the structure of the room, drainage and electrical systems. It is recommended to have work completed by a member of the competent person scheme.

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