Planning permission, permitted development and building regulations
Planning decides whether you can build; building regulations decide how it's built safely. They're separate.
Many small extensions and loft conversions on houses are 'permitted development' and don't need planning permission, but limits apply. Flats, maisonettes, listed buildings and conservation areas have fewer or no permitted development rights, and an Article 4 direction can remove them.
Almost all structural work, new windows, rewiring and drainage needs building regulations approval or a registered installer's certificate. Without it, selling can be difficult.
Listed buildings need listed building consent for most changes, inside and out. Doing work without it is a criminal offence.
What to check
- Check the council's planning history and constraints
- Get a lawful development certificate for bigger permitted development work
- Keep every completion certificate
Who can help
The local planning authority, an architect or planning consultant, and building control.
Official sources
Checked 5 November 2026. General information for England and Wales, not legal advice.