A CAT A fit out is the basic, lettable "blank canvas" flooring, ceilings, lighting and core services usually delivered by the landlord. A CAT B fit out turns that empty shell into a fully operational office with layout, partitioning, furniture and branding, usually paid for by the tenant. CAT A gets a space ready to let; CAT B gets it ready to work in.
What is the difference between a CAT A and CAT B office fit out?
The two categories describe different stages of readiness for the same space.
A CAT A fit out brings a bare unit up to a functional, lettable standard. It's clean and finished, but empty no desks, no meeting rooms, no branding.
A CAT B fit out takes that base and makes it fully functional for a specific occupier. This is where the space becomes a working office tailored to how your team actually operates.
Here's the difference at a glance:
|
CAT A fit out |
CAT B fit out |
| What it is |
Basic finished, lettable space |
Fully operational, occupier-ready office |
| Includes |
Raised flooring and suspended ceilings, lighting, air conditioning, core M&E |
Partitioning, meeting rooms, furniture, finishes, branding |
| State |
Blank canvas / empty shell |
Fully functional workplace |
| Usually paid by |
Landlord |
Tenant |
| Purpose |
Ready to let |
Ready to work |
What is shell and core (and how is it different)?
Before CAT A comes shell and core: the building's structure, external envelope, and communal areas like lifts, stairs and reception, with main services run to the floor but not distributed.
Shell and core is not usable office space. A CAT A fit out is what turns that raw shell into a finished, lettable floor. So the typical order is: shell and core → CAT A → CAT B.
What does a CAT A office fit out include?
A CAT A fit out covers the essential, building-wide elements that make a floor usable but generic. It's designed to suit any future tenant, not a specific one.
A standard CAT A specification typically includes:
- Raised access flooring and suspended ceilings ready for a tenant's cabling and services (see our office flooring work)
- Basic mechanical and electrical services, power distribution, containment and data provision
- Air conditioning and ventilation to base-build standard
- General lighting to an even, functional level
- Basic finishing to walls, plus fire detection and life-safety systems
- WCs and communal facilities brought up to standard
The result is a blank canvas: safe, compliant and ready to occupy, but with no layout or personality yet.
What does a CAT B office fit out include?
A CAT B fit out is where a space stops being generic and starts working for one business. This is the type of fit out most people picture when they imagine an office being built.
A typical CAT B scope includes:
- Partitioning and glazed fronts to create private offices, meeting rooms and quiet zones
- Breakout areas and breakout spaces, kitchens and tea points
- Furniture desks, storage, soft seating and task chairs
- Feature finishes, flooring and design elements that reflect your brand
- Reconfigured M&E data, power and comfort cooling to match the new layout
- Branding, signage and reception to make the space unmistakably yours
Because CAT B is bespoke, cost and timeline vary far more than CAT A. It's driven entirely by your layout, spec and ambition, which is why it starts with proper
office design rather than a shopping list.
Who pays for a CAT A or CAT B fit-out?
As a general rule:
- Landlords fund CAT A, because a lettable space is their product. This cost is often reflected in the rent or headline valuation.
- Tenants fund CAT B, because it's specific to their business and moves with their needs.
There are exceptions. Landlords sometimes contribute to CAT B through a fit-out contribution or rent-free period, and lease terms can shift who does what. Always confirm the split in your heads of terms before work is scoped.
One point tenants miss: altering a landlord's space almost always needs formal consent. Read our guide on the
Licence to Alter before you commit to a CAT B programme.
What is a CAT A+ (plug-and-play) fit-out?
CAT A+ sits between the two categories and has grown quickly as landlords compete for tenants. It's a landlord-delivered, lightly furnished, "plug-and-play" space think basic desks, a kitchen or tea point, a breakout zone and simple meeting rooms already in place.
The appeal is speed: a tenant can move in and work almost immediately, with no full CAT B programme. The trade-off is less personalisation: the layout and finishes are chosen for broad appeal, not your specific brand or ways of working.
CAT A+ is still an emerging, non-standardised term; definitions vary between landlords, so check exactly what's included before you rely on it.
What does each type of office fit-out cost?
There are no fixed industry prices; cost depends on spec, building condition, location and programme. That said, recent 2025–2026 UK fit-out cost guides give useful planning ranges.
| Fit-out type |
Who usually pays |
Indicative UK range (per sq ft) |
| CAT A |
Landlord |
~£35–£65 |
| CAT B (standard / mid-spec) |
Tenant |
~£50–£90 |
| CAT B (high-spec) |
Tenant |
~£90–£150+ |
According to published UK fit-out guides, a CAT A fit-out typically falls between roughly £35 and £65 per square foot, covering base-build services, ceilings, flooring and basic M&E. For CAT B, a standard specification tends to run between about £50 and £90 per square foot, while premium finishes, bespoke joinery and high-end AV can push costs to £90–£150 per square foot or more. Across all categories, industry guides such as Cushman & Wakefield and Turner & Townsend put all-in UK fit-out costs typically in the £40–£125+ per sq ft range, depending on specification, location and furniture.
Two factors that move the number most:
- Location: London projects can attract a 15–30% premium, while regional cities such as Birmingham sit at more competitive mid-range rates. For Midlands businesses, that regional position is a genuine budget advantage.
- Building condition: A recently stripped or new-build shell is cheaper to fit out than older stock with legacy services that need upgrading.
Use these figures for early planning only; a proper space plan will always give you a firmer number.
Which fit-out do you need: CAT A or CAT B?
It comes down to what you're trying to achieve:
- You're a landlord with an empty or dated unit → you need CAT A (or CAT A+) to bring the space to a lettable standard and attract tenants faster.
- You're a tenant who has just leased a CAT A floor → you need CAT B to turn that blank canvas into a working office.
- You're taking on a raw shell → you'll likely need both stages delivered in sequence.
If you want the space to keep pace with hybrid working and future growth, factor that in early. Our guide on
how to future-proof an office interior covers the decisions worth making now.
Why work with one fit-out partner for both stages?
The highest hidden cost in any fit-out isn't materials; it's coordination. Juggling separate flooring, M&E, partitioning and furniture suppliers means gaps, delays and finger-pointing when something slips.
Creative Commercial Environments removes that. As a turnkey
commercial office fit-out partner, we deliver both CAT A and CAT B under one roof, whether a landlord needs a space brought up to a lettable standard or a tenant needs a complete, fully operational office. One team, one point of contact, one accountable partner from design to handover.
That single-partner approach is what keeps projects on time, on budget, and free of the coordination headaches that derail multi-supplier fit-outs.
The Bottom Line: CAT A vs CAT B at a Glance
- CAT A = basic, lettable, empty space (flooring, ceilings, lighting, core M&E) usually the landlord's.
- CAT B = the full, fully operational office (partitioning, meeting rooms, furniture, branding) usually the tenant's.
- Shell and core comes first; CAT A+ is a plug-and-play middle ground.
- Landlords generally pay CAT A; tenants generally pay CAT B, but confirm it in your lease.
- Budget on indicative ranges of ~£35–£65 (CAT A) and ~£50–£150+ (CAT B) per sq ft, with location and building condition as the biggest variables.
Creating a workspace that truly supports productivity, wellbeing and long-term business growth requires more than just good design; it demands expert planning and execution. Creative Commercial Environments delivers tailored office fit-out, refurbishment and design solutions that transform ordinary spaces into high-performing environments built around your team's needs. If you're ready to upgrade your workplace, book a free space-planning consultation with Creative Commercial Environments by calling
0330 441 5936 to start building a workspace that works as hard as you do.
