CAT A (shell-and-core) fit-out is the landlord's base finish -- floors, walls, ceilings and core services, but no partitions or personalisation -- while CAT B is the tenant's tailored fit-out on top of it. The British Council for Offices (BCO) sets out both terms in its Guide to Fit Out, and each stage needs a different post-construction clean.
What is a CAT A fit-out and what cleaning does it need?
CAT A is the base condition a landlord hands over when the occupier isn't yet known: basic floor, wall and ceiling finishes, raised access floors, suspended ceilings, and core mechanical and electrical services, but no partitions, meeting rooms or personalisation, per the BCO's Guide to Fit Out. The post-construction clean at this stage is close to a standard builders/sparkle clean -- removing construction dust and debris, cleaning hard finishes and glazing -- to leave the space market-ready for a prospective tenant to view.
What is a CAT B fit-out and what cleaning does it need?
CAT B is the tenant-specific fit-out built on top of CAT A -- partitions, meeting rooms, kitchens and breakout areas, IT and cabling, furniture and branding, tailored to that occupier. The clean after CAT B works is more detailed: it covers a much wider range of finishes and fittings (soft furnishings, kitchen units, glazed partitions, IT cabinets) and needs closer coordination with the furniture, fixtures and equipment (FF&E) installer, because cleaning often has to happen in stages around other trades still finishing snagging items. See our construction and fit-out cleaning service.
Does the same cleaning contractor cover both stages?
It can, but CAT A and CAT B cleans are usually specified, scheduled and priced separately because they happen at different points in the letting cycle -- CAT A before marketing, CAT B before occupier move-in -- sometimes months or years apart, and sometimes for different clients (landlord vs tenant).
What should be in a CAT A/CAT B cleaning specification?
Confirm the fit-out stage, the exact finishes and fittings involved, who is instructing the clean (landlord or tenant), and the deadline against the move-in or viewing date. See our guide to how builders clean, sparkle clean and final clean map across each stage.
CAT A vs CAT B fit-out cleaning
| Stage | Typical fit-out scope | Cleaning need | Who usually instructs it |
|---|---|---|---|
| CAT A (shell and core) | Base finishes, raised floors, suspended ceilings, core M&E | Builders/sparkle clean to market-ready standard | Landlord / developer |
| CAT B | Partitions, meeting rooms, kitchens, IT, furniture, branding | Detailed clean coordinated around FF&E install and snagging | Tenant / occupier |