Small HMO conversions across Cardiff

In short: A small HMO is a shared house for three to six unrelated people. Across Cardiff, the work is planned around Wales’s HMO rules and the standards the local council publishes.

Nation: Wales
Pricing region: Wales
Postcode areas: CF
Main towns: Cardiff, Whitchurch

What do small HMO conversions (3–6 sharers) in Cardiff involve?

Fire doors to rooms off the escape route
Room-by-room size check before any work starts
Decoration and durable flooring
Second bathroom, shower room or ensuites
Locks, door closers and thumb-turn locks on the exit route
Interlinked smoke and heat detection

Which rules apply in Cardiff?

Councils such as Cardiff and Swansea run additional licensing for HMOs outside the mandatory scheme.
England’s national room sizes do not apply in Wales; councils set their own room standards.
Kitchen and bathroom ratios are set in each council’s HMO standards.
More than 6 sharers is a sui generis HMO and needs planning permission; councils such as Cardiff apply concentration limits.
Fitness for human habitation rules require mains-powered, interlinked smoke alarms on every storey and CO alarms where there is a gas, oil or solid-fuel appliance.

Cardiff Council: local HMO schemes

Additional licensing	In force in part of the council area Cathays: 1 Feb 2023 to 1 Feb 2028. Plasnewydd had a scheme from 1 Jan 2021; check with Cardiff Council whether it has been renewed.
Selective licensing	No scheme found

Schemes change. Check the council’s current pages for the exact address in Cardiff before you buy or start work. Source: Cardiff Council HMO licensing page, checked 2026-10-31.

How much do small HMO conversions (3–6 sharers) cost in Cardiff?

Regional adjustment for Wales. Planning budgets: see our prices page.
Item	UK typical	Local guide	Per
Typical 3–4 bed house to a 5–6 bed HMO, all-in	£30,000 – £75,000	£28,200 – £70,500	project
Conversion works per letting room (walls, linings, electrics, decoration; excludes kitchens, bathrooms and fire systems; our estimate)	£3,500 – £6,500	£3,300 – £6,100	letting room
Shared bathroom refit	£5,500 – £9,000	£5,150 – £8,450	bathroom
Interlinked mains alarm system (Grade D type), small HMO (our estimate from installer guides)	£800 – £2,000	£750 – £1,900	house
FD30S fire door leaf into an existing frame, with seals, closer and hinges, fitted	£300 – £600	£280 – £560	door

Typical time on site: 4–10 weeks. For a figure for your house, try the guide-price tool.

Small HMO conversions (3–6 sharers) by town in Cardiff

Questions about small HMO conversions (3–6 sharers) in Cardiff

Does a small HMO need a licence?

In England a mandatory licence is needed when five or more people from two or more households share, and smaller HMOs can need one where the council runs additional licensing. Wales still applies a three-storey test, while in Scotland and Northern Ireland every HMO needs a licence. We check the address and tell you which applies before quoting.

Can I keep a lounge in a small HMO?

Yes, and many councils expect some shared living space where bedrooms are at the smaller end of the size range. We plan the layout so the house works for sharers and meets the local standard.

Do you carry out small HMO conversions (3–6 sharers) across Cardiff?

Yes, across the whole of Cardiff, including Cardiff, Whitchurch.

Who licenses HMOs in Cardiff?

Cardiff council licenses HMOs in its area. Landlords must also register with Rent Smart Wales.

Small HMO conversions (3–6 sharers) across Cardiff