Basements require both Planning Permission and Building Regulations approval whether constructed as part of a new property or as a retrofit to an existing property. You will need to consult your Local Authority Planning and Building Control offices
The Basement Information Centre publishes a useful industry guide ‘Basements for dwellings’ on basement design and construction and they can be contacted at the following address:
The Basement Information Centre
Riverside House
4. Meadows Business Park
Station Approach
GU17 9AB