Cat A vs Cat B Office Fit-Out: What You Need to Know

Cat A and cat B refer to two different stages of commercial office fit-out. Cat A is the base level: the space is clean, structurally complete, and has basic services installed (raised floors, suspended ceilings, basic HVAC, fire detection, and WC facilities) but is otherwise empty and uninhabitable. Cat B takes the space from cat A to fully occupied - adding partitions, flooring finishes, decoration, kitchen and break areas, meeting rooms, and furniture. Cat B is what a tenant actually moves into and works in.

For a startup, the cat B fit-out decision depends primarily on your lease length and capital position. A traditional cat B fit-out requires upfront capital (typically £50 to £150 per sqm for building works, plus furniture on top), creates a dilapidations liability at the end, and locks in a fixed specification that may not suit your team in 18 months. A cat A space with a circular furniture subscription achieves a similar outcome - a fully designed, professional workspace - without the upfront capital, the dilapidations risk from building works, or the specification lock-in. For most startups, the subscription approach on a cat A space is the better choice.

Cat A fit-out cost depends heavily on the condition of the base build and the level of services already in place. As a working guide, bringing a space from shell to cat A level typically costs £30 to £80 per square metre for a standard commercial space - covering raised floors, suspended ceilings, basic HVAC, and fire detection. Cat B costs on top of cat A typically run £50 to £150 per square metre for building works alone, before furniture. Total cat B fit-out costs in major cities commonly run £100 to £250 per square metre or more for a well-specified space.

Cat A plus - sometimes written cat A+ or cat A+ - is an increasingly common intermediate level offered by landlords as a way to present space that is more immediately occupiable than a bare cat A shell, without the full investment of a tenant-specific cat B fit-out. A cat A+ space typically includes basic partitioning, flooring, decoration, kitchen facilities, and sometimes furniture, pre-installed before a tenant is confirmed. It is designed to reduce the time from lease signing to occupation and is particularly common in speculative fit-outs. A circular furniture subscription fits well on a cat A+ base - the landlord provides the basic fit-out and the tenant layers in designed furniture through a subscription.

Dilapidations are the cost of reinstating leased space to its original condition at the end of the lease. For a cat B fit-out, this typically means removing partitions, making good walls and ceilings, and returning the space to the cat A condition it was in at the start. Dilapidations costs are almost never budgeted at the start of a fit-out and arrive as an unwelcome surprise at lease end. They are one of the strongest arguments for a circular furniture subscription on a cat A or cat A+ base: if you have not built partitions, you have no demolition cost; if the furniture is returned to the provider, there is no furniture disposal to manage.