Can I let a 5m² bedroom in a London HMO?

No — below national 6.51m² minimum for occupant 10+ + above 4.64m² absolute floor. 5m² cannot be bedroom in licensed HMO. £30,000 civil penalty + revocation risk. Reclassify as study + reduce occupancy + amend licence (£280 admin) to remain compliant.

Does a built-in en-suite count toward bedroom area?

No — en-suite bathroom area is separate facility, deducted from bedroom useable area. A 12m² loft bedroom with 2m² en-suite = 10m² remaining = below double minimum (10.22m² national or 11–14m² borough overlay). Design en-suites off corridor or as separate room to preserve bedroom area.

How do I measure useable floor area in a loft bedroom?

Measure floor area where ceiling height is 1.5m or above only — sub-1.5m headroom excluded. Loft conversion with 4.2m × 3.8m footprint typically yields 6.5–8.5m² useable depending on roof pitch + dormer/Velux configuration. Specialist HMO surveyor (£280–£480) measures + reports with scale plan + photo evidence. Plan loft bedrooms as singles unless deeper dormer or hip-to-gable enables double.

Minimum HMO Room Sizes London | Builderr

National minimum + borough overlays + measurement rules

Licensing of HMOs (Mandatory Conditions of Licences) (England) Regulations 2018: mandatory national minimum HMO bedroom sizes — (1) Single occupant 10+: 6.51m² useable; (2) 2 occupants both 10+: 10.22m² useable; (3) Occupant under 10: 4.64m² useable; (4) Below 4.64m²: unfit, cannot be bedroom. Each occupant own bedroom OR lawful shared bedroom (couples, siblings same gender, 2 children under 10 — per LPA + tenancy). Strict no-share for unrelated adults. Borough overlays via HMO licence conditions / local planning policy 2026: Tower Hamlets HMO Standards 2023 (single 9m² + double 14m² — strictest London); Newham Local Standards 2024 (7.5m² + 11m² + ensuite 8+ occupants); Hackney HMO Policy 2021 (single 8.5m² combined with ensuite, double 12m²); Camden Local Standards 2022 (7m² + 10.5m²); Westminster HMO Standards 2020 (7.5m² + 11m²); K&C Local Plan 2022 (8m² + 12m²); Islington HMO Standards 2023 (7m² + 10.5m²); Lambeth HMO Policy 2024 (7m² + 10.5m²). Always check LPA HMO Standards before design. Measurement rules (HMO Standards 2018 guidance + LACORS): useable floor = where ceiling 1.5m+; excludes area under sloping ceiling below 1.5m (loft affected); excludes chimney breast projection (typically 0.4m × 0.9m = 0.36m² deduction); excludes alcoves not accessible; excludes built-in en-suite area (separate facility); excludes built-in wardrobe + cupboard fixed floor-to-ceiling; includes door swing + bay window floor + bed recess if accessible. Wall face to wall face. Loft bedroom challenge: typical Victorian loft 4.2m × 3.8m = 15.96m² gross but only 6.5–8.5m² above 1.5m = often single-only despite gross dimensions. Side-extension bedroom on 22m² ext: 3.5m × 3.5m = 12.25m² gross + chimney breast = 11.85m² double-OK. Specialist HMO surveyor (£280–£480) measures + reports useable area room-by-room before conversion design.

Enforcement + penalty + Builderr design margin + common fails

Enforcement: LPA inspector measures during application + periodic compliance (every 12–24 months on existing HMO). Laser distance meter + scale plan. Tenant complaint triggers re-measurement. Findings: (1) Bedroom below national minimum = licence condition breach + £30,000 civil penalty + likely revocation + RRO; (2) Above national but below borough overlay = condition breach + £30,000 penalty + possible borough enforcement; (3) Occupant numbers exceed licence cap = breach + £30,000 + possible RRO; (4) Bedroom shared by unrelated adults against tenancy = breach + £30,000. Defence: LPA must serve Notice of Intent + 28-day representation before civil penalty. Grounds to challenge: measurement error (independent RICS surveyor £450–£950); useable area dispute (sub-1.5m + chimney breast); occupancy temporary (visitor not occupant). Tribunal appeal 55–70% procedural; 25–35% factual measurement. Builderr design margin — HMO conversion default: exceed national + borough overlay 10–15% — e.g. Tower Hamlets (9m² single overlay) design 10–10.5m²; Newham (7.5m²) design 8.5–9m². Cost premium 5–12% on conversion (£4,800–£14,500 on 4–8 bed) — paid back via faster approval + reduced void + premium rent + safer Tribunal position. Common fails 2026: (1) Loft bedroom measured wrong — 4.2m × 3.8m gross looks fine but only 7.2m² useable = below double, must convert to single. Rent drop £1,800–£3,400/year. Remedy: re-measure + reclassify + reduce occupancy + amend licence (£280); (2) Chimney breast not deducted — 6.8m² gross looks above 6.51m² but with deduction 6.44m² = below. Remedy: remove chimney breast ([[removing-a-chimney-breast-cost-london]] £4,800–£8,500 + structural sign-off) OR reclassify non-bedroom; (3) Loft bedroom with built-in en-suite — gross 12m² with 2m² en-suite = 10m² remaining = below double. Reconfigure en-suite to corridor en-suite OR reclassify single; (4) Bay window recess counted — but ceiling below 1.5m = not useable; (5) Built-in wardrobe counted — fixed = storage not bedroom area. Builderr pre-conversion useable area report (£280–£480) by qualified HMO surveyor measures room-by-room + reports with photo evidence + scale plan = avoids retrospective inspection fail. See [[hmo-amenity-standards-london]] + [[hmo-licensing-london-cost-and-process]] + [[converting-house-to-hmo-london-planning]].

Minimum Room Sizes HMO London 2026