Basic Housing Unit (BHU) Minimum Living Standards:
6 Technical Requirements

8 sq m minimum · including toilet · measured at internal walls

Common non-compliance scenario: Subdivided flats in older buildings constructed before the 1980s often contain units of 6.5–7.5 sq m — "subdivisions within subdivisions" (Owl Square case data, 2018–2026). These typically require units to be merged.

Renovation fix and cost: This is the one requirement of the six that cannot be resolved through renovation alone — the shortfall comes from how the flat was subdivided in the first place. The only realistic route is to knock through and re-partition, merging two undersized units into one that meets the 8 sq m threshold. In practical terms, that means the landlord accepts the loss of one rentable unit rather than paying a renovation bill. If a property has several units in the 6.5–7.5 sq m range, it is worth measuring them yourself before commissioning an Authorized Person assessment, so the assessment fee is not spent on units that renovation cannot fix.

2.3 m minimum · 2.0 m below any beam

Common non-compliance scenario: Rooftop structures, converted loft spaces, and added mezzanine floors frequently fail this requirement.

Renovation fix and cost: Like floor area, ceiling height is largely fixed by the building's structure and cannot generally be "renovated" away. The only scenario where works can help is when a false ceiling, thick screed layer, or raised mezzanine floor is eating into the clear height — removing it may bring the unit into compliance, at a cost of roughly HKD 5,000–15,000 per unit depending on scope (2026 market rate). But where the shortfall comes from an unauthorised rooftop structure or the building's own structural slab spacing, there is usually no economically viable fix. Landlords should measure ceiling height themselves before paying for an assessment on a unit that cannot realistically be brought into compliance.

Option A: natural ventilation (opening ≥ 1/10 of floor area) · Option B: mechanical ventilation (5 ACH + 0.1 sq m window)

Common non-compliance scenario: Units with insufficient window area (below 1/10 of floor area) that also lack a compliant mechanical ventilation system fail both Option A and Option B — one of the most common reasons applications are rejected.

Renovation fix and cost: Of the six requirements, this is the most common — and most straightforwardly fixable through renovation. The fix is installing an Option B mechanical ventilation system (exhaust fan, ducting, and electrical controls) achieving 5 ACH in both the living area and the toilet. Market cost is approximately HKD 5,000–12,000 per unit (2026 market rate), varying with ducting complexity and whether shared exhaust risers need modification. See the full renovation cost breakdown.

Enclosed and waterproofed · flush toilet + washbasin + bathtub or shower · water point and sink outside

Common non-compliance scenario: Shared toilets were common practice in pre-2010 older-style subdivided flats and must now be retrofitted as individual, self-contained facilities. Another frequent gap is a toilet with only a flush toilet and washbasin but no bathtub or shower — the Ordinance requires all three fixtures, so an otherwise "separate" toilet still fails without one.

Renovation fix and cost: If a unit already has a self-contained toilet but lacks a shower or adequate waterproofing, the fix is usually a targeted shower installation and waterproofing job, at relatively contained cost. If the unit has no self-contained toilet at all, one must be built from scratch — partitioning, waterproofing, drainage, and plumbing/electrical connections — costing approximately HKD 25,000–60,000 per unit. Combined with the other required works (fire door, ventilation, utility metering) typically done at the same time, the full renovation package for units needing a new toilet often reaches HKD 60,000–100,000 per unit (2026 market rate). Of the six requirements, this has by far the largest cost impact and should be the first thing confirmed at the assessment stage. See the full renovation cost breakdown.

Separate water meter (Water Supplies Department) · separate electricity meter (CLP/HK Electric)

Common non-compliance scenario: The practice of sharing a single water and electricity meter across an entire floor and apportioning costs by ratio no longer complies with the Ordinance. Separate meters must be applied for through the Water Supplies Department and CLP/HK Electric.

Renovation fix and cost: Apply to the Water Supplies Department and CLP/HK Electric for sub-meters, then have an electrician complete the sub-circuit wiring. Electricity sub-metering costs approximately HKD 3,000–6,000 per unit; independent water meter installation costs approximately HKD 2,000–5,000 per unit (2026 market rate), depending on existing pipe locations. If the building's total electricity meter capacity cannot support sub-metering across multiple units, an additional capacity upgrade may be required at extra cost — landlords should check with CLP/HK Electric in advance. See the full renovation cost breakdown.

FD30 fire door · FRR-60 partition walls · smoke detector · fire extinguisher · FS251 application

Common non-compliance scenario: Timber doors, glass doors, and lightweight steel panel doors are generally non-compliant and must be replaced with approved FD30 fire-resisting doors, with a Fire Services Department FS251 application submitted. Timber-board or aluminium partition walls also frequently fail to reach FRR-60 and are another common cause of rejection.

Renovation fix and cost: Replacing a door with an FD30 steel fire door (including installation, frame, and self-closing device) costs approximately HKD 3,000–5,500 each; doors adjacent to cooking areas may need the higher-rated FD60, at approximately HKD 5,000–8,000 each (2026 market rate). If partition walls fall short of FRR-60, they must be demolished and rebuilt or fitted with fire-rated lining boards, with cost depending on scope. Smoke detectors and fire extinguishers are comparatively low-cost items. See the full renovation cost breakdown.