If the Cat fits: Understanding the difference between Cat A and Cat B fit-outs

When businesses move into a new commercial space, one of the first questions they face is: What kind of fit-out does the property have? The terms Cat A and Cat B are used widely in the property and construction industry to describe the level of finish of an office or commercial unit. But what do they mean, and why does it matter for tenants and landlords?

What is a Cat A fit-out?

A Category A (Cat A) fit-out refers to the basic finishing of a commercial unit. Think of it as a blank but functional canvas; the infrastructure is in place, but the space isn’t yet personalised or ready for immediate occupation by an end user.

A typical Cat A fit-out includes:

Basic mechanical and electrical services (heating, ventilation, and air conditioning – HVAC).

Suspended ceilings with standard lighting.

Raised floors for data and power cabling.

Basic fire detection and safety systems.

Finished internal walls (painted or plastered).

Toilets and basic welfare facilities.

In short, Cat A creates a safe, compliant, and usable shell, but it’s still relatively bare. Tenants can see the space’s full potential but need to add their own layout and branding.

What is a Cat B fit-out?

A Category B (Cat B) fit out is the stage where a workspace is fully customised and made operational for a specific tenant’s needs. This is where the design, functionality, and branding of the business come to life.

A typical Cat B fit-out might include:

Partitioning and room layouts (offices, meeting rooms, breakout areas, etc.).

Floor finishes (carpet, tiles, or timber flooring).

Feature lighting and upgraded fixtures.

Furniture, fittings, and equipment (FF&E).

Decor, colour schemes, and branding.

IT infrastructure and AV equipment.

In other words, a Cat B fit-out transforms the blank Cat A shell into a ready-to-use workspace tailored to the tenant’s operations, culture, and aesthetic.

Why the Distinction Matters

Understanding the difference between Cat A and Cat B fit outs is crucial for budgeting, timelines, and expectations.

Landlords usually provide a Cat A finish so they can offer a neutral, leasable space.

Tenants typically invest in the Cat B stage to ensure the office reflects their brand and meets their operational requirements.

Knowing what’s included at each stage helps avoid misunderstandings, ensures accurate cost planning, and speeds up the move-in process.

Final Thoughts

A Cat A fit-out gives you a functional shell; a Cat B fit-out turns that shell into a fully operational, branded workspace. Whether you’re a landlord preparing a property for lease or a tenant creating a home for your business, understanding these stages will help you make informed decisions about design, costs, and project timelines.

If you’re looking for expert guidance on property fit outs – whether it’s completing both Cat A & B works on a newly built space, transforming a dated interior into a modern environment, or delivering a full building rebrand – NIS Projects is here to help.

Our team can work with you to structure large scale projects, create a clear plan, develop a realistic budget and set out a timeline that turns your vision into reality.

Get in touch with us today on 0207 639 1111 or simply share a few details below and we’ll contact you to discuss how we can support your project.