Guide
Conservation area extension rules
Conservation areas have tighter Permitted Development limits than non-designated streets. Some works that would be PD elsewhere need full planning permission here.
Common restrictions in conservation areas
- Side extensions usually need full planning permission
- Cladding, rendering and roof material changes often need permission
- Outbuildings to the side of the house often need permission
- Larger roof extensions and dormers commonly need permission
Other factors
Listed buildings, AONBs, National Parks and Article 4 Directions can further restrict what you can build. We treat any of these as a designated-land flag in the rules engine.
How to find out
Check your council's online conservation area map or use Defra's MAGIC service. If you're not sure, our check lets you say “Still not sure” and routes conservatively.
Check your project
Run the free planning check for your extension and see the likely route.