Permitted development for lofts
- Up to 40 m³ extra roof space for terraced houses, 50 m³ for semi-detached and detached
- No extension beyond the plane of the roof slope facing a road
- Nothing higher than the highest part of the existing roof
- Dormers set back at least 20 cm from the eaves, as far as practicable
- Side-facing windows obscure-glazed and non-opening below 1.7 m
- No verandas, balconies or raised platforms
- Not available in conservation areas, National Landscapes or for flats
Building regulations
Every loft conversion needs building regulations approval. The main requirements cover the new floor structure, a safe staircase with adequate headroom, fire safety and a protected escape route, and insulation. We handle the drawings, calculations and inspections.
Party walls
On semi-detached and terraced houses, cutting beams into the party wall or raising it normally requires a party structure notice at least two months before work starts. See party wall.
The “10-year rule”
In England, since April 2024, most breaches of planning control become immune from enforcement after 10 years. It's sometimes mentioned in connection with lofts built without approval — but unapproved work causes problems with mortgages and sales long before then. The right approach is to build with the correct approvals from the start.
This guide summarises rules for houses in England at the time of writing and is for guidance only. Rules differ for flats, listed buildings and designated land, and can be changed by Article 4 directions. Always check the Planning Portal or ask us — we confirm the route for your home before design starts.