If you’re planning an office move or refurbishment, you’re likely to come across industry terms like shell and core, Cat A, and Cat B fit out. While they might sound technical, understanding the difference is essential to making the right decisions for your project and avoiding surprises along the way.
Here we break down what each type of fit out means, what’s typically included, and how to choose the right approach for your business.
What is a Shell and Core Fit Out?
Before we get into Cat A and Cat B, let’s take a step back.
A shell and core fit out refers to the most basic stage of a building’s construction. It includes the structural frames and shared areas such as reception, lifts and staircases – but not much else. At this stage, the space is not yet usable and lacks the internal finishes or services needed for any kind of day-to-day business operations.
Typical Features of Shell and Core:
Think of shell and core as the blank foundation on which future fit outs build.
- Structural elements like concrete and steel frames
- Core building services (lifts, stairwells, lobbies)
- Unfinished internal walls and exposed ceilings
- No lighting, air conditioning, or floor finishes
What is a Cat A Fit Out?
A Cat A fit out is the first stage in transforming a Shell and Core space into a functional office, typically carried out by the landlord. This includes the installation of essential infrastructure, such as lighting, raised floors, suspended ceilings, and air conditioning systems, to bring the space up to a presentable standard.
Cat A does not include the finer details that make a space work for a team: no furniture, meeting rooms, or brand elements are present. While it may look finished, it’s not yet ready for people to work in.
Typical Features of Cat A Fit Out:
Cat A creates a ‘blank canvas’, and the next step is adding the final details.
- Raised access floors and suspended ceilings
- Installed lighting and power distribution
- HVAC systems and air circulation
- Painted internal walls and basic finishes
What is a Cat B Fit Out?
A Cat B fit out builds on the functional foundation of a Cat A, transforming the space into a fully operational, bespoke workplace. This is where your business can truly bring its brand, culture, and working style to life.
At this stage, tenants typically collaborate with a design and build expert to shape the space around their specific operational needs, whether that’s focused work zones, collaborative areas, or client-facing environments.
Typical Features of Cat B Fit Out:
Cat B is what turns a space into your space.
- Partitions and internal doors
- Private offices and meeting rooms
- Workstations, seating and storage
- Kitchens, tea points and breakout areas
- Brand graphics, finishes and décor
- IT, AV, and audio-visual integration
Here’s a quick recap of the key fit out types:
- Shell and Core: The structural foundation, with no internal finishes.
- Cat A: A blank, functional canvas, complete but not work-ready.
- Cat B: A tailored, move-in-ready workspace designed around your people and brand.
The right fit out depends on your starting point, lease, and how you want your space to work. Moving into a new building? You’ll likely begin with a Cat A and build out a tailored Cat B. Refreshing your current office? A light Cat B upgrade might do the job. Understanding the difference between Shell and Core, Cat A, and Cat B is key to making smart, future-proof decisions. Whatever your goals, working with an experienced design and build partner ensures your fit out supports your people, reflects your brand, and delivers long-term value.
