An HMO extension adds space to a shared house, usually a ground-floor bedroom with ensuite or a bigger communal kitchen. In Southampton, a place of roughly 270,000 people in Hampshire, the work is planned around the HMO rules for England and the council’s written HMO standards. Southampton has a university population, so many shared houses are let to students on yearly tenancies, and summer is the main window for works.
- Area
- Hampshire, England
- Postcodes
- SO14 and SO15
- Location
- 43 miles south-west of Reading
- Council
- Southampton City Council
- Pricing region
- South East
What do extensions for extra rooms in Southampton involve?
- Kitchen or bedroom fit-out
- Fire separation and detection extended to the new space
- Building control completion
- Heating, insulation and glazing
- Foundations, structure and roof
Which rules apply in Southampton?
Extensions for extra rooms in Southampton 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.
- The Fire Safety Order 2005 applies to the common parts of HMOs, enforced by the fire and rescue authority.
- National rules ask for an adequate number of bathrooms, WCs and basins and suitably located kitchens; numeric ratios are set by each council.
Southampton City Council: local HMO schemes
| Article 4 (HMO) | In force across the council area City-wide Article 4 Direction (C3 to C4) adopted 23 Mar 2012. |
|---|---|
| Additional licensing | In force in part of the council area Additional licensing in nine wards (Banister & Polygon, Bargate, Bassett, Bevois, Freemantle, Millbrook, Portswood, Shirley, Swaythling) 1 Oct 2025-30 Sep 2030. |
| Selective licensing | No scheme found |
Schemes change. Check the council’s current pages for the exact address in Southampton before you buy or start work. Source: Southampton City Council HMO licensing page, checked 2026-10-31.
How much do extensions for extra rooms cost in Southampton?
| Item | UK typical | Local guide | Per |
|---|---|---|---|
| Single-storey extension, about 15 m² | £35,000 – £60,000 | £39,200 – £67,200 | project |
| Single-storey extension per m² | £1,800 – £4,000 | £2,000 – £4,500 | m² |
Use these as a starting point for budgeting. Access, condition and the council’s requirements in Southampton can move the figure either way, which is why we quote after seeing the house.
How long does it take?
Most jobs of this kind take 8–14 weeks. If a council deadline applies in Southampton, tell us at the first call so the programme is built around it.
If the house is let to students, we work backwards from the next tenancy start date in Southampton.
When do Southampton landlords need it?
We usually get the call when:
- A kitchen too small for the number of sharers
- Adding a ground-floor room
Questions about extensions for extra rooms in Southampton
Do you handle building control?
Yes, from application to completion certificate.
Do you cover all of Southampton?
Yes. We work across Southampton and the SO14 and SO15 postcode areas, plus the rest of Hampshire. Nearby places we also cover include Hythe, Totton, Eastleigh.
Which council covers HMOs in Southampton?
Southampton is covered by Southampton City Council. 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 Southampton?
Our guide ranges for South East 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 Southampton
- Hythe · 3 mi
- Totton · 4 mi
- Eastleigh · 5 mi
- Fareham · 10 mi
- Cowes · 11 mi
- Winchester · 12 mi
- All of Hampshire
Other HMO services in Southampton
- Loft conversions for extra rooms in Southampton
- Communal kitchen refits in Southampton
- Layout changes and room reconfiguration in Southampton
- Large HMO conversions (7+ sharers) in Southampton
- Ensuite installation in Southampton
- House to HMO conversion in Southampton
- EPC and energy upgrades in Southampton
- Sound insulation in Southampton