- Nation
- England
- Pricing region
- London
- Postcode areas
- W, E, SW, SE
- Main towns
- London, Brent, Islington, City of Westminster, Bexley
What do extensions for extra rooms in Greater London involve?
- Fire separation and detection extended to the new space
- Foundations, structure and roof
- Building control completion
- Heating, insulation and glazing
- Ensuite drainage and extraction
- Kitchen or bedroom fit-out
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.
- A conversion can be a material change of use under the building regulations, so confirm with building control before work starts.
- 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.
- National rules ask for an adequate number of bathrooms, WCs and basins and suitably located kitchens; numeric ratios are set by each council.
- 7 or more sharers is a sui generis large HMO and normally needs planning permission.
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 extensions for extra rooms cost in Greater London?
| Item | UK typical | Local guide | Per |
|---|---|---|---|
| Single-storey extension, about 15 m² | £35,000 – £60,000 | £44,800 – £76,800 | project |
| Single-storey extension per m² | £1,800 – £4,000 | £2,300 – £5,100 | m² |
Typical time on site: 8–14 weeks. For a figure for your house, try the guide-price tool.
Extensions 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 extensions for extra rooms in Greater London
Is a kitchen extension worth it?
Often, when the existing kitchen limits how many people the council will allow. A bigger kitchen can unlock an extra room.
Can I extend an HMO under permitted development?
Some extensions to houses are permitted development, but rules differ for HMOs and by nation and council. We check the address before design.
Do you carry out extensions 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
- Loft conversions for extra rooms in Greater London
- Communal kitchen refits in Greater London
- Layout changes and room reconfiguration in Greater London
- Large HMO conversions (7+ sharers) in Greater London
- Ensuite installation in Greater London
- House to HMO conversion in Greater London
- HMO fire safety upgrades in Greater London
- Professional and co-living HMO refurbs in Greater London