Cat A vs Cat B Fit-Out: What's the Difference?

Cat A and Cat B are the two standard stages of a commercial fit-out, and the split matters for tendering: they're often delivered by different parties, on different timelines, for different reasons.

Cat A fit-out

Cat A brings a commercial shell to a basic finished standard: raised access floors, suspended ceilings, mechanical and electrical services, basic lighting and fire/life-safety systems compliance. Floor finishes are usually left ready for a tenant's own flooring rather than fully finished. It's the stage that makes a space technically ready for occupation, not the stage that makes it feel occupied.

Cat B fit-out

Cat B is everything on top of that: partitioning, meeting rooms, kitchens and breakout areas, IT and data cabling, branding, furniture and finishes specific to the occupier. This is where a tenant's own designer or architect takes the specification further, and where the space actually starts to look like the business that's moving into it.

Why the split matters when tendering

Knowing which stage you're actually tendering for changes what a fair quote looks like. A landlord scoping a Cat A programme ahead of letting a unit is buying compliance and a blank, serviceable shell, priced mostly on M&E and floor/ceiling systems. A tenant scoping Cat B after signing a lease is buying a finished, branded space, priced mostly on joinery, finishes and furniture, and usually working to a tighter fixed move-in date tied to their own lease break clauses. Conflating the two at tender stage is a common cause of quotes that don't compare like for like, since one contractor's Cat A-only figure and another's combined Cat A plus Cat B figure can look wildly different for what's actually the same building.

Typical programme length

A combined Cat A and Cat B programme on a typical office or retail unit commonly runs 6 to 14 weeks on site, with 8 to 20 weeks total once design, procurement and material lead times are factored in ahead of the on-site start. The range is wide because it depends heavily on the services specification and how much of the Cat B scope is bespoke joinery and fitted finishes versus off-the-shelf furniture.

We deliver both stages, either as separate phases for a landlord and incoming tenant, or as a single combined programme where we're engaged for the whole fit-out, and take on principal contractor responsibilities under CDM 2015 where the project calls for it.