Do I need planning permission to convert a house to an HMO?

Not always. A change from a family house to a small HMO for 3 to 6 people is usually permitted development, unless an Article 4 direction applies. A large HMO for 7 or more people always needs planning permission. External works may need permission in their own right.

Does every HMO conversion need building regulations approval?

Not every one, but many do. A conversion may be a material change of use, depending on the facts, and building work such as structural changes, new bathrooms, drainage, fire separation and electrics normally needs approval or a competent person scheme.

How many bathrooms does an HMO need?

Your council's HMO amenity standards set the number of bathrooms and toilets for a given number of occupiers, and the figures vary between councils. Check them before you fix the number of bedrooms, because an extra room can trigger the need for another bathroom.

What tenancy do HMO room tenants have now?

Since 1 May 2026, most private tenancies, including individual room lets, are assured periodic tenancies with no fixed term. Tenants can leave on 2 months' notice, and landlords can end a tenancy only on a possession ground, as section 21 has been abolished.

Converting a house to an HMO: step by step

What are the steps to convert a house into an HMO?

Most conversions follow the same sequence. Getting the order right avoids paying for work that has to be redone.

Check the address for planning, Article 4 and licensing before you buy.
Survey and test the feasibility: measure the house and work out how many rooms it can lawfully hold.
Settle the planning route: permitted development, a lawful development certificate or a planning application.
Design the layout to room sizes, council amenity standards and a fire strategy.
Apply for building regulations approval where it is needed.
Carry out the works to a fixed, itemised specification.
Collect the certificates and building control sign-off.
Apply for the HMO licence where one is needed.
Let the rooms under the rules in force since 1 May 2026.

The rest of this guide takes each step in turn.

What should I check before buying a house to convert?

The checks that matter most are about the address, not the house:

Article 4. Is there an Article 4 direction removing the right to change a family house into a small HMO? If so, you will need planning permission even for 3 to 6 people.
Planning policy. If you need permission, what do the council's HMO policies say about concentration and sandwiching in that street?
Licensing. Does a mandatory, additional or selective licensing scheme apply? Our HMO licensing checker is a quick first step.
Council standards. What are the local room size and amenity standards for kitchens and bathrooms?
Title and lease. Do any covenants or lease terms restrict multiple occupation? Your solicitor should check.
Mortgage and insurance. Will your lender and insurer accept HMO use? Take regulated advice on finance.

A house that looks perfect can be the wrong buy if the street is in an Article 4 area with a high concentration of HMOs already.

How do I work out how many rooms a house can have?

Start with a measured survey. Every bedroom needs to meet the national minimums for licensed HMOs: 6.51 m² for one person aged over 10 and 10.22 m² for two people aged over 10, with floor under a ceiling lower than 1.5 m left out. Your council may set higher local standards.

Then check the shared facilities. Council amenity standards set how many bathrooms and toilets, and what size of kitchen, are needed for a given number of people. An extra bedroom can push the house over a threshold that calls for another bathroom or a larger kitchen, which changes the cost.

Finally, check the escape route. A protected route from each room to the outside, and any lobbies the fire strategy needs, take up space. Our HMO feasibility appraisals test room counts against all three before you commit. See also our guide to HMO room sizes.

How do planning and design fit together?

The planning route depends on the number of residents:

3 to 6 residents, no Article 4 direction. The change from a family house to a small HMO is usually permitted development under Class L. A lawful development certificate gives formal confirmation if you want certainty.
3 to 6 residents, Article 4 area. You need planning permission for the change of use.
7 or more residents. A large HMO is sui generis and always needs planning permission.

External works such as dormers, extensions or new windows may need permission in their own right. Design and planning should run together: the drawings for a planning application should already show room sizes, kitchen and bathroom provision, bin and cycle storage and a workable fire escape route, so the approved layout is also licensable. Our guide to HMO planning and Article 4 covers the detail.

Does an HMO conversion need building regulations approval?

Often, yes. A conversion may be a material change of use under the Building Regulations 2010, for example where the building newly contains rooms for residential purposes such as bedsit-style lettings, or where the number of such rooms changes. Where it is, the converted building must meet set requirements including fire safety (Part B), and in most cases sound insulation (Part E), ventilation, drainage, electrical safety and energy.

Whether a particular change counts depends on the facts. A shared house let as one dwelling may not be a material change of use, while bedsit-style rooms are. Separately, the building work itself, such as structural alterations, new kitchens and bathrooms, drainage, fire separation and electrics, normally needs building control approval or a competent person scheme.

You can use local authority building control or a registered building control approver. A private approver gives the council an initial notice before work starts. Agree the fire strategy with building control and, ideally, the council's licensing team before work begins, because licensing may expect more than the building regulations minimum.

What happens during the building works?

A typical HMO conversion programme includes:

strip-out and any structural alterations;
first-fix plumbing and electrics, including new circuits for kitchens and en-suites;
fire separation: fire-resisting linings to the escape route, fire-stopping around services and new partitions;
en-suite shower rooms, the communal kitchen and any extra shared bathroom;
fire doors, commonly FD30 or FD30S with self-closers, and a mains-wired interlinked alarm system, depending on the layout, size, fire risk assessment and the council's HMO standards;
emergency lighting where the fire risk assessment calls for it;
heating, ventilation, decoration and floor finishes.

Building control inspects at set stages. Changes during the build can affect room sizes, the fire strategy and cost, so agree the specification in writing first. We work to a fixed written quote for the agreed specification, itemised, with a programme agreed before work starts. See our HMO conversions service and our guide to HMO conversion costs.

Which certificates do I need at the end of an HMO conversion?

Before you apply for a licence and let the rooms, gather:

Building regulations completion certificate or final certificate, where the work needed approval.
Gas safety record from a Gas Safe registered engineer, renewed at least every 12 months.
Electrical installation condition report (EICR) from a qualified person, before the tenancy starts and then at least every 5 years. New installation work will also have its own certificates.
Fire alarm and emergency lighting certificates for the systems installed.
Fire risk assessment for the common parts.
Energy performance certificate where one is needed.
Measured floor plans showing room uses and floor areas.

Our gas, electrical and alarm certificates service keeps these in date after handover.

When should I apply for the HMO licence?

Where the house needs a licence, plan for the application to go in before the house is occupied at a licensable level. Letting a house that needs a licence without one is an offence, with a civil penalty of up to £40,000 and rent repayment orders of up to 2 years' rent.

The council will want the application form, the fee it sets, floor plans, certificates and details of the licence holder and manager. It may inspect before deciding. Ask the council how it handles applications for newly converted houses, as practice varies. Our HMO licence applications service prepares and submits the paperwork. See also HMO licensing explained.

How do I let the rooms under the Renters' Rights Act?

Since 1 May 2026, room lets in a shared house are normally assured periodic tenancies with no fixed term. In practice:

publish an asking rent for each room and do not seek or accept offers above it;
take no rent before the tenancy agreement is signed, and no more than one month's rent between signing and the start date;
give a written statement of terms for each new tenancy;
do not refuse applicants because they have children or receive benefits;
answer any pet request within 28 days and do not refuse unreasonably;
give new tenants a copy of the gas safety record before they move in, and the EICR as the regulations require;
check the smoke and carbon monoxide alarms are working on the first day of each tenancy.

Tenants can leave on 2 months' notice, so plan for rooms to turn over at any point in the year. Our Renters' Rights Act guide covers the detail, and our room lets and tenant find service handles advertising, referencing and move-in.

Sources

This guide explains the rules in England as we understood them in October 2026. It is general information, not legal or financial advice. Check with your council and take professional advice for your own situation.

How to convert a house into an HMO