In short: An HMO loft conversion adds one or two letting rooms, often with an ensuite, in the roof space. We carry this out across Greater London, priced against the HMO rules for England and the council’s own standards.
- Nation
- England
- Pricing region
- London
- Postcode areas
- W, E, SW, SE
- Main towns
- London, Brent, Islington, City of Westminster, Bexley
What do loft conversions for extra rooms in Greater London involve?
- Dormer or roof windows
- Feasibility and head-height check
- Planning or permitted development check
- New stair within the protected route
- Ensuite where space allows
- Building control sign-off
Which rules apply in Greater London?
- 3–6 unrelated sharers is use class C4; changing from a family house is usually permitted development unless an Article 4 direction applies.
- Building regulations cover structural changes, new partitions, ensuite drainage, fire-resisting construction and notifiable electrical work.
- Fire precautions follow a risk assessment; the LACORS Housing – Fire Safety guide (2008) is guidance, not law, but many councils base their standards on it.
- Floor area under a ceiling lower than 1.5 m does not count towards the room size, and many councils set larger sizes.
- Mandatory HMO licence for 5 or more people in 2 or more households (since October 2018); councils can add additional licensing for smaller HMOs.
Councils in England can add additional licensing and Article 4 directions on top of the national rules. Check the council’s website for the exact address before you buy or start work.
How much do loft conversions for extra rooms cost in Greater London?
| Item | UK typical | Local guide | Per |
|---|---|---|---|
| Dormer loft conversion, about 30 m² | £40,000 – £60,000 | £51,200 – £76,800 | project |
| Rooflight loft conversion, about 30 m² | £22,500 – £30,000 | £28,800 – £38,400 | project |
Typical time on site: 6–10 weeks. For a figure for your house, try the guide-price tool.
Loft conversions for extra rooms by town in Greater London
- London
- Brent
- Islington
- City of Westminster
- Bexley
- Barking
- Archway
- Sutton
- Croydon
- Ilford
- Enfield Town
- Harrow
- Tottenham
- Walthamstow
- Dagenham
- Becontree
- Romford
- Hayes
- Wembley
- Fulham
- Edmonton
- Southall
- Putney
- Battersea
- Canary Wharf
- Purley
- Peckham
- Chingford
- Uxbridge
- Wimbledon
- Stamford Hill
- Brixton
- Hounslow
- Finchley
- Cricklewood
- Mitcham
- Feltham
- Acton
- Beckenham
- Chelsea
- Streatham
- South Croydon
- Leytonstone
- Eltham
- Morden
- Carshalton
- Catford
- Willesden
- Canning Town
- Holloway
- Welling
- Shepherds Bush
- Surbiton
- Greenford
- Heston
- Stratford
- Chiswick
- Thamesmead
- Ruislip
- Greenwich
- Barnet
- Kilburn
- Wood Green
- Muswell Hill
- Bow
- Highbury
- Camden Town
- Northolt
- Coulsdon
- Hornchurch
- Blackheath
- Isleworth
- Chalk Farm
- New Malden
- Hanworth
- Woodford Green
- Hadley Wood
- Richmond
- Barnes
- Notting Hill
- Wallington
- Pimlico
- Hampton
Questions about loft conversions for extra rooms in Greater London
Will the loft room count for licensing?
Only the floor area with at least 1.5 metres of headroom counts towards the room size in England.
Does adding a loft room change the HMO planning position?
It can. Going from six to seven sharers moves a house into a large HMO in England, which normally needs planning permission. We check before design.
Do you carry out loft conversions for extra rooms across Greater London?
Yes, across the whole of Greater London, including London, Brent, Islington.
Who licenses HMOs in Greater London?
HMOs in Greater London are licensed by the local council for the address. Where an area has several councils, each runs its own licensing and planning policies.
Other HMO services in Greater London
- Extensions for extra rooms in Greater London
- Large HMO conversions (7+ sharers) in Greater London
- Escape routes, emergency lighting and fire stopping in Greater London
- Ensuite installation in Greater London
- Layout changes and room reconfiguration in Greater London
- Fire alarm and detection systems in Greater London
- Professional and co-living HMO refurbs in Greater London
- Communal kitchen refits in Greater London