Most industrial tenants assume the office corner, the small showroom, or the staff pantry in their unit is just part of the fit-out. It isn’t. URA treats that space as a distinct use category, ancillary use, and caps how much of it a B1 or B2 development can carry. Get the ratio wrong and you’re looking at a change-of-use rejection, a directive to reinstate, or a stalled renovation permit.
This matters most to occupiers converting a bigger share of their unit to office or client-facing space than the operation actually needs, and to buyers assessing whether a unit’s existing office fit-out is even compliant. Understanding the ancillary use rule tells you how much office, showroom, or canteen space your unit can legally carry, what counts toward that limit, and how to verify a specific unit’s position before you sign or renovate.
What “Ancillary Use” Actually Means
Under URA’s Development Control guidelines, every B1 (light industrial) or B2 (general industrial) development is split into two categories: predominant industrial use and ancillary (or supporting) use. Predominant use covers manufacturing, assembly, repair and servicing, and storage tied to an industrial operation. Ancillary use covers everything that exists to support that operation without being industrial itself: ancillary offices, meeting rooms, pantries, sick rooms, showrooms, and a short list of permitted commercial functions.[1][2]
The rule that governs the split is commonly called the 60:40 rule. At least 60% of a B1 or B2 development’s total gross floor area (GFA) must be used for industrial purposes. No more than 40% can go to ancillary use.[1][3]
Two things trip up most occupiers here:
- It’s a GFA ratio, not a room count. A unit can have an office, a pantry, and a small showroom and still comply, as long as their combined floor area stays under 40% of the unit’s GFA.
- An independent office or shop is not an ancillary use. URA’s guidelines are explicit that a standalone office or retail unit does not qualify as industrial use at all, no matter how it’s dressed up in a floor plan. If the “ancillary” office isn’t actually supporting an industrial operation on the same premises, it isn’t ancillary; it’s a change of use that industrial zoning doesn’t permit.[2]
How the 40% Cap Applies in Practice
The cap works at two levels, depending on the building.
Single-user (non-strata) developments. If one owner occupies the whole building, the 60:40 split applies to the entire development. If that owner sub-leases parts of the building to multiple tenants, the development is treated the same as a multi-user building for quantum purposes: the single-owner exemption doesn’t survive subletting.[1]
Multi-user (strata) developments. Here the cap applies twice: once across the whole development, and once inside each individual strata unit. Common areas (corridors, staircases, lifts, toilets, M&E rooms) count toward the development-level ancillary quantum, but each unit owner still has to keep their own unit at a minimum 60% industrial use, with ancillary space capped at 40% of that unit’s GFA.[1][3]
This second point is what catches most buyers off guard. A unit can look compliant on its own floor plan and still breach the rule once the strata title area and the actual fitted-out office proportion are checked against URA’s records. The reverse also happens: a unit bought with an oversized office fit-out already in breach, inherited from a previous owner who never had it regularised.
What Counts as Ancillary Use
URA’s Allowable Uses guidelines for B1 and B2 developments list specific categories, each with its own conditions. The main ones relevant to occupiers:
| Ancillary use | Condition |
|---|---|
| Ancillary office, meeting rooms, sick rooms | Must directly support the industrial operation on the same premises; not an independent office |
| Showroom | Confined to the first storey; limited to bulky items or products predominantly installed off-site; incidental small-item sales only |
| Ancillary display area | For corporate/demonstration purposes tied to the development’s own products; no direct public sales; no strata subdivision of the display area |
| Industrial canteen | Capped at 700 sqm or 5% of total development GFA, whichever is lower; approved on Temporary Permission |
| Selected commercial uses (clinics, banking facilities/ATMs, minimarts, fitness centres) | Only in outlying industrial estates away from commercial nodes; capped at 200 sqm or 10% of GFA, whichever is lower; first storey only; Temporary Permission |
| Diesel/pump points, M&E services | Standard supporting infrastructure |
Showrooms and the selected commercial uses above are approved under Temporary Permission (typically renewed periodically), not as a permanent right. URA revisits them and can withhold renewal or require re-approval.[4][2]
One temporary exception worth knowing: with effect from 10 February 2023, URA raised the allowable ancillary quantum from 40% to 49% specifically for applications involving temporary workers’ dormitories within industrial developments. The underlying 60% industrial-use floor still applies to everything else in the same building; the extra 9% is earmarked for dormitory use, not general office expansion.[5]
Why the Ratio Matters Beyond Zoning Compliance
Getting the ancillary proportion wrong doesn’t just risk a URA enforcement letter. It shows up at several points in an occupier’s or buyer’s process:
- Fit-out and renovation approval. If your renovation plans push office or showroom area past the cap, the plan submission (via JTC or a Qualified Person acting for URA) gets flagged, and you’ll be asked to revise before works can proceed.
- Change-of-use applications. JTC is explicit that any change-of-use application must keep at least 60% of the premises industrial. An application that converts more than 40% to office or retail-style use will not be approved as submitted.[6]
- Due diligence on resale or sub-lease. A buyer or incoming sub-tenant inheriting a unit with an existing office fit-out needs to confirm that fit-out was actually approved at its current proportion, not just that it exists. Unapproved excess ancillary space is the seller’s or outgoing tenant’s problem to have disclosed, but it becomes the new occupier’s problem to fix.
- Property tax. IRAS taxes non-residential property, including industrial premises, at a flat 10% of Annual Value regardless of the internal use mix, so the ancillary/industrial split doesn’t change the tax rate. It does, however, factor into how IRAS assesses comparable rents when setting the Annual Value in the first place.[7]
Verifying a Unit’s Ancillary Use Position
Before signing a lease, buying a unit, or planning a renovation that adds office or showroom space, verify these:
- Check the unit’s approved use and GFA breakdown via URA’s Enquiry on Approved Use of Premises e-service, or ask the landlord/seller for the approved building plans showing the industrial-versus-ancillary split.[8]
- Confirm whether any showroom, canteen, or commercial use in the building is on Temporary Permission, and when that permission is next due for renewal. It is not a permanent grant.
- Measure your actual intended ancillary area against the unit’s total GFA, not just against the space you’re physically renovating. A unit that’s already at 35% ancillary use from existing fit-out has very little room left for anything new.
- For strata units, check both levels. The development-wide ancillary quantum and your own unit’s quantum can diverge, especially in older multi-user buildings where common-area allocations were set decades ago.
- For any change beyond straightforward office/pantry use (a customer-facing showroom, a canteen open to non-staff, a dormitory conversion), submit a formal application through JTC (for JTC-managed land) or URA rather than assuming an existing precedent in the building applies to your unit.
Common Mistakes
The most frequent one is treating “ancillary” as a design choice rather than a regulated ceiling: fitting out a generous office because the space allows it physically, without checking the GFA math against the rest of the unit. The second is assuming a showroom or canteen precedent set by a previous tenant transfers automatically; Temporary Permission approvals are tied to the specific use and applicant, not to the unit indefinitely. The third is confusing “ancillary office” with “independent office.” If the office function doesn’t support an industrial process happening in the same unit, URA doesn’t recognise it as ancillary use at all, and the 40% cap doesn’t even apply because the use itself is the wrong category.
Takeaway
The ancillary use rule is a GFA ratio, not a floor-plan aesthetic. Sixty percent of a B1 or B2 unit has to carry the actual industrial function; the remaining 40% is the ceiling for everything supporting it, and specific categories inside that 40% (showrooms, canteens, selected commercial uses) carry their own size caps and Temporary Permission terms on top. Before signing, buying, or renovating, get the unit’s approved-use breakdown from URA rather than relying on what the current fit-out looks like.
For the broader zoning context this sits inside, see B1 vs B2 zoning in Singapore, what “B1 only” means on a landlord’s terms, and URA/JTC change-of-use basics. If you’re not sure how to classify your unit’s floor area for an application, how to describe production vs storage vs office use and the business activity fit guide walk through the same categories from the application side.
References
[1] URA — Business 1 (Industrial): Use Quantum. https://www.ura.gov.sg/Corporate/Guidelines/Development-Control/Non-Residential/B1/Use-Quantum
[2] URA — Business 2 (Industrial): Allowable Uses. https://www.ura.gov.sg/Corporate/Guidelines/Development-Control/Non-Residential/B2/Allowable-Uses
[3] URA — Business 2 (Industrial): Use Quantum. https://www.ura.gov.sg/Corporate/Guidelines/Development-Control/Non-Residential/B2/Use-Quantum
[4] URA — Revised Guidelines for Supporting Uses in Industrial Developments (Circular DC14-24). https://www.ura.gov.sg/Corporate/Guidelines/Circulars/dc14-24
[5] JTC — Conversion to workers’ dormitories. https://www.jtc.gov.sg/get-help/managing-your-tenancy-or-lease/conversion-to-dormitories
[6] JTC — Changing the use of your industrial property. https://www.jtc.gov.sg/get-help/managing-your-tenancy-or-lease/changing-the-use-of-your-industrial-property
[7] IRAS — Understanding your Industrial Property Annual Value. https://www.iras.gov.sg/taxes/property-tax/property-owners/annual-value/understanding-your-industrial-property-annual-value
[8] URA eService — Enquiry on Approved Use of Premises. https://eservice.ura.gov.sg/EnquiryOnApprovedUse/