The Town and Country Planning (General Permitted Development) (England) Order 2015 (GPDO) permits the change of use from a single-family home (C3) to a small HMO (C4, 3-6 unrelated occupants) without a planning application in most of England. However, local planning authorities can remove this right using an Article 4 Direction, which is in force in dozens of university towns and high-density rental areas.
Operating an HMO without required planning permission is a planning offence. Check with your local planning authority before any conversion — permitted development rights cannot be assumed.
HMO use classes
- C3 (Dwellinghouse): single household, family, or couple — a standard home or single-household rental
- C4 (Small HMO): 3 to 6 unrelated people sharing amenities (kitchen, bathroom) — student houses, professional sharers
- Sui Generis (Large HMO): 7 or more unrelated people — always requires full planning permission, no permitted development route
When is C3 to C4 permitted development?
GPDO 2015 Schedule 2 Part 3 Class L permits C3 to C4 change of use as permitted development provided: no Article 4 Direction applies; the property is not listed; the property is not in certain protected landscape designations; and no planning condition removes permitted development rights.
Article 4 Directions: where they apply
- In force in: Oxford, Cambridge, Nottingham, Southampton, Portsmouth, Leeds, Leicester, Exeter, Liverpool, Coventry, Brighton, Sheffield, many London boroughs, and other cities
- Coverage varies: some directions cover the whole local authority; others only specific wards near universities or rental hotspots
- Check: go to the local planning authority website and search 'Article 4 HMO', or call the planning department duty officer
- If an Article 4 Direction applies: submit a full planning application for change of use from C3 to C4 before converting
Consequences of unlawful conversion
- Planning enforcement notice requiring restoration to previous use (potentially removing tenants)
- Enforcement registered as a local land charge, appearing in any future property search
- HMO licence refusal if planning permission was not obtained
Even where permitted development applies, consider applying for a Certificate of Lawful Use (CLU) to formally confirm the conversion is lawful. This protects you on sale and remortgage and costs £258 (2026 application fee).