Planning Permission Basics for Extensions and Conversions

Planning permission vs building regulations

They are separate. Planning controls what you build and how it is used; building regulations control how it is built — structure, fire safety, insulation, ventilation and more. Many projects that don't need planning permission still need building regulations approval.

Permitted development

Some extensions, loft conversions and alterations to houses can be carried out under permitted development rights, within strict limits on size, height and position. Flats and maisonettes do not have the same rights. Some larger single-storey rear extensions need prior approval from the council.

Where rights are restricted

• Listed buildings — listed building consent is needed for works affecting character
• Conservation areas, National Parks and other designated land
• Article 4 directions that remove specific rights
• Planning conditions on the original permission

Lawful Development Certificates

If you believe a project is permitted development, a Lawful Development Certificate from the council confirms it. It is optional but valuable for lenders, buyers and peace of mind.

Making a planning application

Good drawings, a clear design rationale and early engagement with local policy improve your chances. Consider pre-application advice from the council for more complex schemes. Neighbours may need to be notified under the Party Wall etc. Act 1996 where works affect shared walls or nearby foundations.