You may not need planning permission. Some home improvements are allowed under permitted development rights, but others do require consent.
When Planning Permission is Needed
You will usually need permission for:
- New buildings or major extensions
- Changes to the use of a building or land
- Work to listed buildings or in conservation areas
- Alterations to the roof or front of the property
- Projects in national parks, World Heritage sites or Areas of Outstanding Natural Beauty
When You May Be Exempt
Some work falls under permitted development and may not need permission:
- Small extensions within size and height limits
- Internal alterations
- Rooflights or dormers that meet set criteria
- Garden buildings within defined limits
- Porches under a certain size
Always check with your local planning office before starting work.
Permitted Development – Key Limits
- Only half the land around the original house can be built on
- Extensions cannot be higher than the roof or built forward of the front
- Materials must match the existing house
- No balconies, verandas, or raised platforms
- Extra rules apply in conservation areas and similar designated zones
- Side extensions and cladding often need full permission
Loft Conversions
Permitted if:
- Roof space added is within volume limits (40m3 for attached homes, 50m3 for detached)
- No extension projects beyond the roof slope facing the road
- Dormers are set back from the eaves
- Side windows must be obscure glazed and positioned over 1.7m from floor
- No balconies or raised platforms
Rear Extensions
- Depth up to 4m for detached houses, 3m for others (or more with prior approval)
- Height limits apply if close to boundaries
- Two storey rear extensions limited to 3m depth and must match roof height and pitch
- Upper windows in side walls must be obscure glazed
Porch Extensions
- Max external footprint of 3m²
- Max height 3m
- Must be at least 2m from boundaries or roads
At Axminster Design and Build, we help you check your project against all local rules.
Book a free consultation to discuss your plans.