An HMO extension adds space to a shared house, usually a ground-floor bedroom with ensuite or a bigger communal kitchen. For a house in Willesden we start with a measured survey, check the council’s written HMO standards for the number of sharers, and then price each item separately.
- Area
- Greater London, England
- Postcodes
- NW10
- Location
- 5 miles west of London
- Council
- London Borough of Brent
- Pricing region
- London
What do extensions for extra rooms in Willesden involve?
- Fire separation and detection extended to the new space
- Planning route check and drawings
- Kitchen or bedroom fit-out
- Foundations, structure and roof
- Heating, insulation and glazing
Which rules apply in Willesden?
Extensions for extra rooms in Willesden must satisfy national law for England, the council’s written HMO standards and, where walls, drainage or fire separation change, the building rules. In short:
- 7 or more sharers is a sui generis large HMO and normally needs planning permission.
- Building regulations cover structural changes, new partitions, ensuite drainage, fire-resisting construction and notifiable electrical work.
- Smoke alarms on every storey with living accommodation and CO alarms by fixed combustion appliances (other than gas cookers) are required by law.
- Council standards often step up at 5 and 6 sharers, for example a separate WC at 5 and a second bathroom from 6.
London Borough of Brent: local HMO schemes
| Article 4 (HMO) | In force across the council area Borough-wide Article 4 Direction (C3 to C4) since 1 Nov 2022. |
|---|---|
| Additional licensing | In force across the council area Borough-wide additional licensing in force 2 Feb 2026 to 1 Feb 2031. |
| Selective licensing | In force in part of the council area All wards except Wembley Park: Dollis Hill, Harlesden & Kensal Green, Willesden Green 1 Aug 2023-31 Jul 2028; 18 further wards 1 Apr 2024-31 Mar 2029. |
Schemes change. Check the council’s current pages for the exact address in Willesden before you buy or start work. Source: London Borough of Brent HMO licensing page, checked 2026-10-31.
How much do extensions for extra rooms cost in Willesden?
| 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 |
These are typical ranges including VAT, adjusted for London, where costs run above the UK average. The fixed price for a house in Willesden follows a site visit.
How long does it take?
Most jobs of this kind take 8–14 weeks. If a council deadline applies in Willesden, tell us at the first call so the programme is built around it.
When do Willesden landlords need it?
Typical reasons for this work in Willesden:
- Adding a ground-floor room
- A kitchen too small for the number of sharers
Questions about extensions for extra rooms in Willesden
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 cover all of Willesden?
Yes. We work across Willesden and the NW10 postcode areas, plus the rest of Greater London. Nearby places we also cover include Cricklewood, Notting Hill, Shepherds Bush.
Which council covers HMOs in Willesden?
Willesden is covered by London Borough of Brent. We read the council’s written HMO standards before pricing, and you should check the licence position for the exact address.
How much do extensions for extra rooms cost in Willesden?
Our guide ranges for London are in the table on this page, and the guide-price tool gives a figure for your house. A fixed written quote follows a free site visit.
Extensions for extra rooms near Willesden
- Cricklewood · 2 mi
- Notting Hill · 2 mi
- Shepherds Bush · 2 mi
- Kilburn · 2 mi
- Acton · 2 mi
- Chiswick · 3 mi
- All of Greater London
Other HMO services in Willesden
- Loft conversions for extra rooms in Willesden
- Communal kitchen refits in Willesden
- Layout changes and room reconfiguration in Willesden
- Large HMO conversions (7+ sharers) in Willesden
- Ensuite installation in Willesden
- House to HMO conversion in Willesden
- Shared bathroom and shower room refits in Willesden
- Bedroom upgrades and room refits in Willesden