HMO Room Size Requirements in London: Minimum Sizes, Licensing Rules, and Space Standards

**The national minimum room sizes (Housing Act 2004 / 2018 Amendment)**:

The Licensing of Houses in Multiple Occupation (Mandatory Conditions) (England) Regulations 2018 (which came into force on 1 October 2018) introduced mandatory minimum room sizes for all mandatory licensed HMOs in England. These are:

• •*Single occupant room (sleeping accommodation for 1 adult)*: Minimum 6.51m² (70 ft²) of floor area
• •*Shared occupant room (sleeping accommodation for 2 adults)*: Minimum 10.22m² (110 ft²) of floor area
• •*Room used by a child aged 10 or under*: Minimum 4.64m² (50 ft²) of floor area

*What counts as 'floor area' for the room size calculation?*:

• The floor area measurement excludes areas where the ceiling height is less than 1.5m (5ft). In rooms with sloping ceilings (typically loft conversion bedrooms under a pitched roof), only the area where the ceiling is at least 1.5m high is counted toward the room size minimum. In practice, for a loft bedroom in a typical London pitched-roof loft conversion:
• •The total floor area of the room may be, say, 9.0m² — but if 2.0m² is under a 1.5m ceiling slope, only 7.0m² counts for the purposes of the HMO minimum room size test
• •For a loft bedroom to provide a comfortable and compliant single HMO room, targeting a minimum 7.5–8.0m² of usable (ceiling >1.5m) floor area is advisable, with a minimum 2.0–2.1m clear head height over at least 50% of the floor area

*What the 2018 regulations require of landlords*:

• If an HMO licence holder is notified (by the local housing authority) that a room is below the minimum size:
• •The landlord has 18 months from the date of notification to either increase the room size (if physically possible) or stop using the room for sleeping
• •Rooms already below the minimum size at the time of licensing were given a transitional period — most of these transitional periods have now expired
• •New HMO licences issued after 1 October 2018 are subject to the minimum sizes from the start

**London borough additional room size requirements**:

Many London boroughs apply standards that are MORE STRINGENT than the national minimum. These are applied through the local housing authority's HMO licensing conditions or through planning policy for new HMO conversions.

*Common additional London borough standards*:

| Standard type | National minimum | Common London borough requirement | |---|---| | Single occupant bedroom (sleeping only) | 6.51m² | 8.0m²–10.0m² | | Single occupant bedroom (living room use) | 6.51m² | 10.0m²–12.0m² | | Double occupant bedroom | 10.22m² | 12.0m²–15.0m² | | Minimum room dimension | No national minimum | 2.0m–2.5m minimum shortest dimension (to prevent excessively narrow rooms that meet area but not function) |

• Examples of London boroughs with stricter standards (as of 2025, confirm with the relevant housing authority):
• •*Newham*: Requires rooms used as sole living and sleeping accommodation to be minimum 10.0m² for single occupancy
• •*Barnet*: Applies additional space standards above the national minimum in its HMO SPD
• •*Ealing*: HMO licensing conditions include standards for room sizes and minimum dimensions
• •*Southwark*: Planning policy for new HMO conversions requires compliance with London Plan space standards

*Always check the specific local authority's HMO licensing conditions and any relevant Supplementary Planning Document (SPD) for HMOs* — these take precedence over this summary and vary between boroughs.

**The national space standard (for new housing) vs HMO minimum sizes**:

The Mayor of London's London Plan 2021 sets minimum space standards for new residential dwellings in London. These are significantly more generous than the HMO minimum room sizes but apply to new-build housing and residential conversions creating new self-contained dwellings (not to HMOs per se). However, some London boroughs apply London Plan space standards to HMO conversions through planning policy — making the effective minimum room sizes for new HMO conversions in those boroughs more stringent than the Housing Act 2004 national minimum.

• *London Plan minimum bedroom sizes (for information)*:
• •1-bed (2-person) flat: 50m² minimum gross internal area (GIA)
• •2-bed (4-person) flat: 70m² minimum GIA
• •These are whole-dwelling standards, not individual room standards, but they inform the approach some boroughs take to HMO room sizes in planning policy

**Amenity ratios for HMOs — bathroom, WC, and kitchen provision**:

The national minimum HMO licensing conditions (Housing Act 2004 schedule and local authority licensing conditions) specify minimum ratios of amenity facilities (bathrooms, WCs, kitchens) to occupants:

• *National minimum bathroom/WC ratios*:
• •1 bath or shower for every 5 occupants
• •1 WC for every 5 occupants (WC may be separate from bath/shower room or combined)
• •In practice, many London local authorities require higher ratios in their licensing conditions

• *Common London borough additional requirements*:
• •1 bath or shower for every 4 occupants (some boroughs)
• •1 WC for every 3–4 occupants (some boroughs)
• •Shared WCs and bathrooms: must be within or immediately accessible from a common area (not accessed through another person's bedroom)

*En-suite provision*: Where each bedroom has its own private en-suite bathroom and WC, the shared bathroom ratio rules are typically satisfied for each occupant (each has their own facilities). En-suite provision is increasingly standard in new London HMO conversions — tenants in London command higher rents for en-suite bedrooms, and the investment in en-suites typically produces better rental yield per unit of floor area. See `hmo-conversion-cost-london-2025` for HMO conversion cost context.

• *Kitchen provision*:
• •Minimum: 1 kitchen per HMO (all occupants share one kitchen)
• •Many London boroughs require 1 kitchen per 5 occupants for mandatory licensed HMOs
• •Kitchen area minimums vary: some boroughs require minimum 7.0m² kitchen area for 5 occupants; some require minimum 10.0m² for 6+ occupants
• •In large HMOs (7+ occupants), some boroughs require a second kitchen

**Room type definitions and what qualifies as a bedroom in an HMO**:

Not every room can be used as a bedroom in an HMO — the Housing Act 2004 and local authority licensing conditions define what constitutes an acceptable 'sleeping accommodation':

• *A room qualifies as sleeping accommodation if it*:
• •Meets the minimum floor area (6.51m² national minimum, or higher local standard)
• •Has adequate natural light (a window of adequate size — typically 1/10 of the floor area minimum for habitable room standards under BS 8206)
• •Has adequate ventilation (trickle ventilators + opening window — see `building-regulations-part-f-guide`)
• •Has adequate ceiling height — Part L and habitability standards require minimum 2.0m over at least 50% of the floor area; many local authorities require minimum 2.1m in HMO rooms
• •Has or is within reasonable access of a fire door (FD30S) where required by the HMO fire safety risk assessment
• •Has adequate heating — at least one form of fixed heating (not portable heater)

• *Rooms that typically DO NOT qualify as bedrooms in an HMO*:
• •Former dining rooms less than 6.51m² (especially in Victorian London houses where small reception rooms may be 4–5m²)
• •Attic rooms where the majority of floor area is below 1.5m ceiling height
• •Basement rooms without adequate natural light (windows below external ground level that provide inadequate daylight — subject to daylight assessment)
• •Integral garage rooms without adequate natural light and ventilation
• •Converted outbuildings that do not have planning permission for residential use

**The room size planning test for change of use to HMO**:

In most London boroughs, converting a house to a small HMO (C3 → C4 use class, 3–6 occupants) is within permitted development — no planning permission is required. However, many London boroughs (particularly those with Article 4 Directions — Southwark, Hammersmith and Fulham, Lewisham, Newham, and others) have removed this permitted development right, requiring a full planning application for any C3 → C4 conversion.

• Where a planning application is required, the planning authority will assess:
• •Room sizes against the local authority's HMO SPD or planning policy
• •Impact on neighbours (noise, increased footfall, waste)
• •Impact on the character of the area (parking, amenity space)
• •Whether the property is in an area where HMO concentration is considered excessive (Article 4 areas are often specifically targeted)

For HMOs with 7 or more occupants (Large HMOs — Sui Generis use class), planning permission is ALWAYS required — regardless of Article 4.

**Practical guidance on room planning for a new London HMO conversion**:

When planning a new HMO conversion in London, the following approach minimises compliance risk:

*Step 1 — Check the local authority's HMO licensing conditions*: Before designing anything, obtain the current HMO licensing conditions from the relevant London Borough housing department. These will set out the room size minimums, amenity ratios, fire safety requirements, and any other local standards that will govern the licence conditions. These vary between boroughs and are updated periodically.

*Step 2 — Check Article 4 Direction status*: Confirm whether the property is within an Article 4 Direction area that requires planning permission for C3 → C4 conversion. Check the local authority's planning portal or Article 4 Direction map. If Article 4 applies, a planning application is required before conversion works start.

• *Step 3 — Room size plan*:
• Prepare a floor plan showing each bedroom with measured dimensions and floor area. For rooms with sloping ceilings (loft rooms), indicate the line of 1.5m ceiling height and calculate the usable floor area. For each room:
• •Is the usable floor area ≥ 6.51m² (national minimum) AND ≥ local authority minimum?
• •Is the minimum room dimension adequate (≥ 2.2m minimum in all directions is good practice)?
• •Is there adequate natural light (window area ≥ 1/10 floor area)?
• •Can an en-suite be added within the room without reducing the room below the minimum area?

*Step 4 — Amenity calculation*: Calculate the number of shared bathrooms and WCs required for the proposed number of occupants, using the local authority's ratios. If en-suites are provided to all rooms, shared facilities are not required for those occupants.

*Step 5 — Fire safety risk assessment*: For any HMO, a fire safety risk assessment (FSRA) is required — see `hmo-fire-safety-guide` for detail. The FSRA will specify fire door requirements, alarm system type, emergency lighting, and means of escape provisions that must be integrated into the conversion design.

**Common HMO room size compliance failures in London**:

*1. Measuring total floor area rather than usable floor area in loft rooms*: Counting the full floor area of a loft bedroom (including area under the slope where the ceiling is less than 1.5m) leads to overcounting — the room appears to comply with the minimum size but is measured incorrectly. Always calculate usable floor area (ceiling ≥ 1.5m) for loft rooms.

*2. Narrow rooms that meet area but not function*: A room measuring 1.5m × 5.0m = 7.5m² meets the national minimum area for a single room — but is barely usable as a bedroom (a single bed is 0.9m × 1.9m, leaving 0.6m on each side). Many local authorities have a minimum room dimension requirement (typically 2.0–2.5m minimum narrowest dimension) that prevents such rooms. Even where no minimum dimension is specified, licensing officers can refuse rooms they consider inadequate for habitation.

*3. Former dining room or box room below minimum size*: Small reception rooms and box rooms in Victorian London terraces (very common in Hackney, Islington, Lewisham) can be as small as 3–5m² — well below the 6.51m² national minimum. These cannot be used as bedrooms in an HMO. Many novice HMO landlords assume any room can be a bedroom — the minimum size rule is fixed and non-negotiable for licensed HMOs.

*4. Basement rooms without adequate daylight*: Basement bedrooms in London Victorian houses are common — but many have windows that are level with or partially below the external ground level, with limited daylight penetration. The daylight standard for a habitable room requires adequate natural light for normal daytime activities without artificial lighting — typically assessed using the Building Research Establishment (BRE) 'sky factor' method. Basement rooms that fail the daylight test cannot be used as HMO bedrooms.