If you’ve been reading a lease, an agent’s particulars, or a fit-out proposal, you’ve probably hit the terms “Cat A” and “Cat B” without anyone stopping to explain them. You’re not alone. These terms get thrown around constantly in commercial property, usually on the assumption that everyone already knows what they mean. They don’t. Get the distinction wrong, and you can end up budgeting for the wrong scope of work. Or you might discover partway through negotiations that you’re expected to pay for something you assumed was already included.

What This Guide Covers

We work across both categories regularly. That means fitting out shells for landlords, and fitting out for tenants moving into a space that’s already had its Cat A finish. This guide explains what each term means, who typically pays for what, and the questions worth asking before you sign anything.

Shell and Core: The Starting Point

Before Cat A or Cat B comes into the conversation, there’s shell and core: the building in its most basic form. The structure, external walls, windows, lift and stair cores, and main building services are in place. But there are no internal finishes: no raised floors, no suspended ceilings, and no partitioning. If you’ve ever walked into a newly built office block that’s still exposed concrete, bare risers and hanging cables, that’s shell and core.

Very few tenants take on a space at shell and core stage directly. It’s more commonly the starting point for a developer or landlord, who then builds it up to Cat A before marketing it to tenants. That’s because a shell and core space is hard for most businesses to picture, let alone occupy.

What a Cat A Fit-Out Actually Includes

Category A, almost always shortened to Cat A, is the base level of finish a landlord typically provides to make a space lettable. It generally includes raised access flooring, a suspended ceiling, basic mechanical and electrical services, lighting, and window blinds. The shell is finished and decorated, ready for a tenant to move their own fit-out into. What it doesn’t include is anything specific to how a tenant wants to use the space. There are no partitioned meeting rooms, no branded reception, no kitchen or breakout area, and usually no raised floor finish beyond a basic screed or the floor tiles themselves.

Think of Cat A as a blank canvas. The services already run to the ceiling void and floor void, ready for a tenant to build their own layout on top. It’s the standard a landlord will typically deliver as part of a lease, and it’s what most tenants inspect when viewing available office space.

Cat A+ (Cat A Plus)

Some landlords go a step further, delivering what’s often called Cat A+ or Cat A plus. This adds elements such as basic partitioned meeting rooms, a simple breakout area, and sometimes furniture, on top of the standard Cat A specification. Landlords typically use it to make a space more attractive and quicker to occupy, particularly in a competitive letting market, which can shorten the time a tenant needs before moving in. Cat A+ sits between Cat A and Cat B. Exactly what’s included varies significantly from one landlord to the next, so it’s always worth getting a specific list of inclusions rather than assuming what “Cat A+” covers.

What a Cat B Fit-Out Actually Includes

Category B, or Cat B, is the tenant’s own fit-out, built on top of whatever Cat A specification the landlord has provided. This is where the space becomes genuinely yours. It typically covers partitioning to create meeting rooms, private offices and breakout areas, floor finishes such as carpet tiles, and ceiling adjustments where needed. It also covers branding, signage, kitchen and washroom upgrades, IT and data cabling, furniture, and any acoustic or fire-rated partitioning your layout requires.

A Cat B fit-out is entirely tailored to how a specific business works. Two tenants taking identical Cat A units in the same building might end up with completely different Cat B fit-outs. One might favour open-plan desking with a handful of meeting rooms, the other a more cellular layout with private offices throughout. This is also where most of the decisions covered elsewhere on our blog come into play: what type of partitioning to specify, whether a suspended ceiling needs adjusting, and what fire compartmentation the new layout requires.

Who Typically Pays for What

This is where the terms matter most in practice, because they directly affect your budget. A landlord will usually deliver Cat A as part of the base lease, sometimes described as bringing the space “up to Cat A standard” before marketing it. The tenant is then generally responsible for their own Cat B fit-out, at their own cost. That said, it’s increasingly common for landlords to offer a Cat A+ specification, a fit-out contribution, or a rent-free period, specifically to offset a tenant’s Cat B costs on longer leases or larger units.

None of this is fixed by law or universal convention. It’s negotiated as part of the lease or heads of terms. So it’s worth clarifying explicitly, in writing, exactly what specification the space will be handed over in, and what contribution, if any, the landlord is making towards your own fit-out. Assuming a shared understanding of “Cat A” without confirming the detail is one of the most common sources of dispute between tenants and landlords. It tends to surface once a fit-out is already under way.

Dilapidations: What Happens When You Leave

The other side of this conversation is what happens at the end of a lease. Many leases require a tenant to “reinstate” the space: stripping out their Cat B fit-out and returning it to Cat A condition, or sometimes further back to shell and core, at their own cost. This is a real and often underestimated cost of leaving a space, separate entirely from the cost of fitting out your next one. It’s worth understanding your reinstatement obligations at the point you sign a lease, not when you’re already planning your exit.

Practical Tips Before You Sign or Start Planning

Frequently Asked Questions

Know Where the Line Sits Before You Sign

Cat A and Cat B aren’t just industry jargon. They describe a genuine division of responsibility between landlord and tenant, one that affects your budget, your timeline, and what you’re legally on the hook for at the end of a lease. Understanding where the line sits before you sign anything means fewer surprises. It means a fit-out costed against what’s actually there rather than a guess, and a clearer conversation with your landlord from day one.