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Planning permission

The planning regime covering the creation of living space in basements is evolving and under review.

Converting an existing residential cellar or basement into a living space is in most cases unlikely to require planning permission as long as it is not a separate unit or unless the usage is significantly changed or a light well is added, which alters the external appearance of the property.

Excavating to create a new basement which involves major works, a new separate unit of accommodation and/or alters the external appearance of the house, such as adding a light well, is likely to require planning permission.

If you live in a listed building you are likely to need consent for internal or external work.

In all circumstances you are advised to contact your local planning authority for guidance on local policy before starting any work.

Find your Local Planning Authority

Build Aviator's estimating service can help you plan your project by providing an accurate cost of the proposed construction. Find out more1.

Once costs have been estimated, the quick quote finance calculator2 from Selina Advance can take all of the hard work out of searching and securing the funds needed for your project.

Find a Trade Professional

Use our partner directories from RIBA, FMB, or RTPI to find an architect, builder or planning consultant to help with your project or development.

Find a trade professional


Useful links

Make an application Project estimating service


Planning consultancy calculator Financing your project
    1. https://www.planningportal.co.uk/permission/home-improvement/estimating-service
    2. https://www.planningportal.co.uk/permission/home-improvement/quick-quote-finance-calculator

    The Planning Portal is delivered by PortalPlanQuest Limited which is a joint venture between TerraQuest Solutions Limited and the Department for Levelling Up, Housing & Communities. All content © 2022 Planning Portal.

    The Planning Portal is delivered by PortalPlanQuest Limited which is a joint venture between TerraQuest Solutions Limited and the Department for Levelling Up, Housing & Communities. All content © 2022 Planning Portal.