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HMO conversion step by step
An HMO conversion turns a house into a shared let. Check what counts as an HMO, then planning, layout and money. Term HMO mortgages fund the finished house.
Is the property suitable?
Demand, storeys, room sizes and amenity standards decide this. Skip a house that cannot take a second bathroom or a protected escape.
Planning and Article 4
C3 to C4 can be permitted development unless Article 4 removes it. Seven-plus occupiers is usually sui generis and needs HMO planning permission.
Building regulations and fire safety
Layout, drainage, electrics and fire need building-control sign-off. Detection and doors follow the Fire Safety Order, LACORS and the 2006 management regulations.
Design: room sizes, kitchens, bathrooms
Licensed sleeping minima in England are 6.51m² and 10.22m² for two. Councils add amenity ratios. Draw to the local PDF first.
Conversion costs
No published national cost per room. Budget these lines; get quotes.
| Line | What drives it |
|---|---|
| Fire and escape | Storeys and occupancy |
| Kitchens and bathrooms | Local amenity ratio |
| Consents | Article 4, sui generis, building control |
| Fees | Drawings, licence, bridge interest |
Financing a conversion
Fund works with HMO bridging finance, HMO refurbishment mortgages or development finance, then refinance.
Licensing after conversion
Five or more occupiers generally need a mandatory licence in England. Additional schemes catch smaller houses. Apply before letting.
Timeline
Planning can take months; works and the licence add more. Do not let until both are clear.
Pros and cons
Higher rent if the layout works; planning risk, fire cost and voids if it does not.
FAQs
How much does a HMO conversion cost?
Quotes on the house, not a national per-room rate.
Is it always worth converting to a HMO?
No — refusal, small rooms or a weak exit can wipe the yield.
Can I convert my house into a HMO?
If planning, building regulations and licensing can be met.
What is the 4 year rule for garage conversion?
A planning-enforcement time limit, not an HMO rule.
Can I convert my garage into a bedroom without planning permission?
Sometimes; building regulations and HMO size and fire tests still apply.
What is the 2.5 metre rule?
An outbuilding height rule, not the 6.51m² HMO bedroom test.
How much does it cost to convert a house to an HMO?
The checklist above, plus finance if you are on a bridge.
Do I need planning to convert to an HMO?
Yes under Article 4 or at seven-plus occupiers; C3 to C4 may otherwise be permitted development.
How long does an HMO conversion take?
Months; longer if planning and a heavy rebuild are required.
How do I finance an HMO conversion?
Bridge, refurbishment or development finance, then a term mortgage.
What building regulations apply?
Those covering the notifiable work: fire, structure, electrics, drainage, energy.