Subdivided Flat vs BHU:
What Changed After 2026?
“Subdivided flat” — commonly known in Cantonese as sup fong (劏房) — is the everyday term people, media and landlords use for any partitioned rental unit. It has never had a legal definition. “Basic Housing Unit” (BHU, 簡樸房) is the formal legal category created by the Basic Housing Units Ordinance (Cap. 658) — it refers specifically to a subdivided unit that has passed Housing Bureau recognition. The two terms are not interchangeable; one describes a widespread physical reality, the other a formal legal status. This guide explains the practical difference, which subdivided flats will never become (or need not become) BHUs, and the timeline landlords must follow now that the Ordinance is in force.
Subdivided Flat vs BHU: Five Key Differences
| Comparison | Subdivided Flat (劏房) | BHU (簡樸房) |
|---|---|---|
| Legal status | Colloquial term, no legal definition | Formal legal category under Section 2 of Cap. 658 |
| How it's obtained | Automatic — any partitioned unit let separately is a subdivided flat | Requires a specified professional's on-site inspection and Housing Bureau recognition |
| Lawful to let after March 2027? | No, unless registered/certified — otherwise unlawful | Yes, throughout the certification's validity period |
| Validity period | No concept of “validity” | 60 months from the recognition date, renewable |
| Scope | Covers any subdivided rental unit, including industrial buildings, illegal rooftop structures, etc. | Applies only to eligible subdivided units within domestic buildings |
Source: Basic Housing Units Ordinance (Cap. 658), Sections 2, 4, 6 and Schedule 4 Part 2.
How “Subdivided Flat” and “BHU” Relate to Each Other
The word “subdivided flat” (or its Cantonese original, 劏房) does not appear anywhere in the text of the Basic Housing Units Ordinance. The statute instead uses the formal term “subdivided unit.” Section 4 defines it: a flat in a domestic building that has been partitioned, or re-partitioned, in a way not shown on the referenced building plans, resulting in 2 or more compartments of which at least 2 are designed as separate residential tenancy subjects. This is, in substance, what people colloquially call a “subdivided flat” or 劏房.
“BHU” is a different concept entirely. Section 2 defines it precisely: a basic housing unit means a subdivided unit that has a valid BHU recognition. In other words, a BHU is not a distinct physical building type — it is the legal designation a subdivided unit earns once it passes the recognition process and holds a valid certificate issued by the Housing Bureau.
The relationship can be stated in one line: every BHU is a subdivided flat, but not every subdivided flat is — or will become — a BHU. “Subdivided flat” describes physical reality (a unit partitioned and let separately); “BHU” describes legal status (recognised as meeting minimum living-condition standards). Media coverage consistently pairs the two terms (“subdivided flats (劏房), now regulated as basic housing units (簡樸房)”) precisely because this is a transition: the Ordinance's purpose is to build a regulatory pathway for existing subdivided flats, so eligible units can formally “graduate” into BHUs.
Three Key Differences: Legal Status, Certification Requirements, Rental Eligibility
For landlords, “subdivided flat” and “BHU” are not just different labels — they carry three concrete practical consequences:
First, legal status. Being a subdivided flat is not itself an offence — simply partitioning and letting a unit is lawful. Liability arises under Section 8 (effective 1 March 2027): when a flat has neither valid grace-period registration nor its subdivided units valid BHU certification, and it is still let out, that is when the offence is committed.
Second, certification requirements. Moving from “subdivided flat” to “BHU” requires a Section 17 application: made by the owner of the principal flat, accompanied by the prescribed fee and a report from a specified professional — and that report must be based on an actual on-site inspection (Section 17(2)); document review alone is not sufficient. The professional must confirm the unit meets Schedule 1's minimum standards of living conditions (floor area, ceiling height, ventilation, a private toilet with a flush toilet, washbasin and bathtub/shower, fire safety, independent water and electricity metering, and more) before issuing a qualifying report.
Third, rental eligibility. From 1 March 2027, a unit that remains merely a “subdivided flat” — unregistered and uncertified — and continues to be let commits an offence for the person letting it out. By contrast, a unit that has obtained BHU certification may lawfully be let under the “basic housing unit” designation throughout its 60-month validity period, unaffected by Section 8.
Not Every Subdivided Flat Will (or Needs to) Become a BHU
This is where many landlords get it wrong — assuming every subdivided flat must eventually be BHU-certified. In fact, a meaningful share of subdivided flats sit entirely outside the Ordinance's scope, or are structurally incapable of passing certification.
- Units in industrial or commercial buildings (not “domestic buildings”)
- Bedspace lodging houses (separately regulated under Cap. 447)
- Transitional housing and Light Public Housing units
- Hotels, guesthouses, elderly homes, residential care homes for persons with disabilities, child care centres (Schedule 4 Part 2)
- Subsidised sale flats (HOS, Green Form Subsidised Home Ownership) before the premium is paid
- Internal floor area under 8 sq m with no way to merge units or move partitions
- Ceiling height below 2.3 m due to an unmovable structural element (e.g. a load-bearing beam)
- Unable to meet either ventilation option (natural or mechanical)
- Rooftop structures or illegal structures (expressly excluded from “subdivided unit” under Section 4(4))
For full details, see our guide on which subdivided flats cannot be BHU-certified. Note that a subdivided flat in an industrial building falling outside Cap. 658 does not mean it is free of legal risk — such units commonly involve use-related breaches under the Buildings Ordinance, and landlords should not treat “not covered by BHU certification” as a reason to keep letting it out.
What Subdivided-Flat Landlords Must Do Since 2026
The Basic Housing Units Ordinance has taken effect in two stages since 1 March 2026, creating two milestones every subdivided-flat landlord within scope must track:
- Fee: HKD 0 (Schedule 2, during the registration period)
- Deadline: 28 February 2027
- Document submission only — no physical works
- Keeps the existing subdivided flat lawfully rentable during the transition
- Fee: as low as HKD 0 for early registrants — three tiers (HKD 0 / 1,500 / 3,000) depending on registration and application timing
- Requires a specified professional's on-site inspection
- Grants the right to let the unit as a “basic housing unit”
- Valid for 60 months from the recognition date
These are independent steps — complete grace-period registration first to secure protection during the transition, then plan BHU certification (and any needed renovation) based on the unit's actual condition. See our guides on BHU certification fee structure and the complete BHU compliance timeline for exact figures and dates.
⚠️ What Happens If a Subdivided-Flat Landlord Does Nothing?
From 1 March 2027, Section 8 takes full effect: letting a unit in a flat with neither valid grace-period registration nor valid BHU certification is a criminal offence. On summary conviction: a Level 6 fine plus 2 years' imprisonment. On indictment: a fine of HKD 300,000 plus 3 years' imprisonment. Both carry a further HKD 20,000 per continuing day. From 1 September 2029, no new tenancy may be signed for an uncertified unit (existing tenancies may run to expiry). From 1 March 2030, grace-period protection ends entirely — every subdivided flat across Hong Kong must hold a valid BHU certificate to be lawfully let.
Three Things Subdivided-Flat Landlords Should Do Now
-
Confirm whether your unit falls within Cap. 658
If the property is an industrial building, bedspace lodging house, or another Schedule 4 Part 2 category, it is outside the Ordinance — no registration or certification is required, though other Buildings Ordinance compliance issues may still apply. -
Complete grace-period registration before 28 February 2027
Landlords within scope should submit grace-period registration to the Housing Bureau as soon as possible — free of charge, document-only, no renovation required. -
Commission a specified professional assessment and move toward BHU certification
Under Section 17(2), the professional must conduct an on-site inspection, assess the unit against Schedule 1 minimum standards, and help plan any required renovation — leading to a formal 60-month BHU certification.
Frequently Asked Questions
Is a subdivided flat (劏房) the same thing as a Basic Housing Unit (簡樸房)?
Not exactly. “Subdivided flat” (colloquially known in Cantonese as sup fong, 劏房) is the everyday term for any residential unit that has been partitioned for separate rental — it has no legal definition. “Basic Housing Unit” (BHU, 簡樸房) is the formal legal category under the Basic Housing Units Ordinance (Cap. 658): a subdivided unit that has passed Housing Bureau recognition and holds a valid BHU certificate. Every BHU started out as a subdivided flat, but not every subdivided flat is (or can become) a BHU.
Does my subdivided flat have to become a BHU?
It depends on the unit's use and building type. If the unit sits within a domestic building (or the domestic portion of a composite building) and is rented out, grace-period registration and BHU certification are generally required. If the property is an industrial or commercial building, a bedspace lodging house, transitional housing, Light Public Housing, a hotel/guesthouse, or another Schedule 4 Part 2 category, it falls entirely outside the Ordinance and cannot (and does not need to) apply for BHU certification. See our guide on which subdivided flats cannot be BHU-certified.
What actually changed for subdivided-flat landlords since the Ordinance took effect in 2026?
The Basic Housing Units Ordinance took effect in stages from 1 March 2026, creating two obligations: first, grace-period registration (deadline 28 February 2027, fee HKD 0), which lets existing subdivided flats continue to be lawfully let during the transition; second, BHU certification (fee HKD 0/1,500/3,000 depending on registration timing), which grants the unit a formal, legally recognised status valid for 60 months. From 1 March 2027, a subdivided flat that has neither grace-period registration nor BHU certification and is still let out is operating unlawfully.
What happens if a subdivided-flat landlord does nothing?
Once Section 8 of Cap. 658 took effect on 1 March 2027, letting out a subdivided unit with neither valid grace-period registration nor valid BHU certification is a criminal offence: on summary conviction, a Level 6 fine plus 2 years' imprisonment; on indictment, a fine of HKD 300,000 plus 3 years' imprisonment; both carry a further HKD 20,000 per continuing day. From 1 September 2029, no new tenancies may be signed for uncertified units. From 1 March 2030, grace-period protection ends entirely.
How do I tell if my subdivided flat is already a BHU?
Check whether the unit holds a valid BHU certificate issued by the Housing Bureau, still within its 60-month validity period. If the unit has only completed grace-period registration but not certification, it remains legally a “registered subdivided unit” — not a BHU. These are two distinct legal states. For a fuller comparison, see Grace Period vs Immediate Compliance: Which Should You Choose?