HMO Conversion in London — Planning, Licensing, and What Landlords Need to Know

An HMO is a property occupied by three or more people from two or more separate households, who share facilities such as a bathroom or kitchen.

Mandatory HMO licensing applies to properties with five or more people from two or more households sharing facilities. These must be licensed with the local authority regardless of borough.

Additional licensing schemes are introduced by individual London boroughs to cover smaller HMOs (typically three or more people) and apply to properties in the designated area. The majority of Inner London boroughs now operate additional licensing schemes. Check your specific borough — the licensing requirements vary significantly.

Selective licensing applies to all privately rented properties in designated areas, not just HMOs. Several London boroughs operate selective licensing across large parts of their area.

Operating an HMO without the correct licence is a criminal offence, with fines of up to £30,000 per breach and potential rent repayment orders for up to 12 months of rent.

C4 Use Class (Small HMO — 3 to 6 unrelated residents): In most areas, converting a property from C3 (single family dwelling) to C4 (small HMO) is Permitted Development — no planning permission is required. However, many London boroughs have removed PD rights for C3 to C4 changes by Article 4 Direction. This includes large parts of several Inner London boroughs.

Sui Generis (Large HMO — 7 or more residents): Converting to a large HMO (Sui Generis) always requires planning permission regardless of location.

Before assuming you can convert to an HMO without planning, confirm with your local planning authority whether an Article 4 Direction removing C3 to C4 PD rights applies to your property's location. Proceeding without the correct planning status can result in enforcement action.

Fire safety is where most HMO compliance failures occur, and London Fire Brigade and environmental health officers inspect HMOs in detail. Key fire safety requirements include:

Fire detection:

• Grade D, Category LD2 or LD3 interlinked smoke alarm system as a minimum
• Heat alarm in kitchen
• Smoke alarms outside sleeping rooms (in corridors and landings)
• Carbon monoxide detectors where applicable

Fire doors:

• FD30S fire doors (30-minute fire-resisting, with self-closer and intumescent strips) to all bedroom doors
• FD30S doors to kitchen (fire origin room) in properties with inner room risk
• Appropriate sealing at doorframes

Means of escape:

• A protected escape route from each floor to the exit
• Where staircases are not protected, alternative means of escape (e.g. fire-protected corridors) may be required
• On higher floors (third floor and above), additional fire safety measures are typically required

Fire separation:

• The loft space above the top-floor rooms must be properly fire-separated from the accommodation
• Communal areas must be separated from individual rooms by fire-resistant construction

Emergency lighting:

• Required in HMOs of three or more storeys and in other specified configurations

The specific fire safety requirements for your HMO depend on the number of storeys, number of occupants, and the configuration of the property. A Fire Risk Assessment (FRA) is the correct starting point.

London local authorities set minimum standards for HMO room sizes. National minimum room sizes (from Housing Act 2004 regulations in force since 2018):

• Sleeping room for one adult: minimum 6.51m2
• Sleeping room for two adults sharing: minimum 10.22m2
• Children aged 10 and over: minimum 4.64m2

Many London boroughs apply higher minimum standards than the national minimum. Check your borough's HMO licensing standards.

Bathroom and kitchen ratios: London local authorities typically require a minimum ratio of one bathroom per four or five occupants and one kitchen (or kitchen facilities) of a minimum standard. The specific requirements are set in each borough's licensing conditions.

Energy performance: From 2028, new EPC regulations are expected to require a minimum EPC rating of C for rental properties. HMO conversions being undertaken now should consider insulation, glazing, and heating efficiency with this in mind.

Converting a standard London Victorian terrace to a 5–6 bedroom HMO typically involves:

Structural:

• Dividing existing large bedrooms into multiple smaller rooms (may require structural work if load-bearing walls are involved)
• Creating en-suite shower rooms in each bedroom (very common in London HMOs — reduces bathroom ratio pressure and commands higher room rents)
• Potentially adding a loft conversion to create additional rooms

Fire safety:

• Replacing all bedroom and kitchen doors with FD30S fire doors
• Installing intumescent strips and door closers throughout
• Installing interlinked Grade D smoke and heat alarm system
• Upgrading fire separation at ceilings between floors if required
• Emergency lighting installation

M&E (Mechanical and Electrical):

• Rewire to modern standard and add a circuit for each room (to manage individual consumption)
• Install en-suite plumbing for each new shower room
• Kitchen upgrade or new communal kitchen installation
• Additional gas boiler capacity or multiple boilers if demand warrants it
• Internet and TV infrastructure

Decoration and fit-out:

• All rooms to a lettable standard
• Communal areas decorated to a clean, professional standard
• Flooring throughout

Costs vary enormously with the scope of conversion, number of rooms, and existing condition of the property. Indicative ranges for a London Victorian terrace:

• 5-bedroom HMO conversion from C3 (basic — fire doors, alarms, minor works only): £20,000–£40,000
• 5-bedroom HMO conversion with en-suites to all rooms: £60,000–£100,000
• 6-bedroom HMO with en-suites and full rewire: £80,000–£140,000
• Larger or more complex HMOs with loft conversion: £120,000–£250,000+

These figures include contractor labour and contractor-supplied materials but exclude furniture, white goods, and landlord-supplied fixtures.

Once the works are complete and the property meets the required standards, a licence application is submitted to the council with:

• Gas Safe certificate
• Electrical Installation Condition Report (EICR)
• Fire alarm commissioning certificate
• Tenancy agreement template
• Proof of ownership and identity
• Application fee (varies by borough — typically £500–£2,000 for a 5-year licence)

The council may inspect the property before issuing the licence.

rcbGroup offers a full HMO conversion service covering:

• Pre-conversion consultation and specification
• Fire safety design with reference to local authority standards
• Full construction management
• Building Regulations management
• Coordination with fire safety inspectors and environmental health
• Handover documentation package for licence application

Contact rcbGroup for a free initial assessment of your property.