What is the difference between a CAT A Fitout and a CAT B Fitout?

As a construction company operating across the UK, 4construct has extensive experience in delivering a wide spectrum of commercial fit-out projects. From the initial structural elements to the final bespoke touches, we understand that navigating the terminology of office fit-outs can be complex. Two of the most commonly encountered classifications are "CAT A Fitout" and "CAT B Fitout," and distinguishing between them is crucial for landlords, developers, and prospective tenants alike.

At 4construct, we pride ourselves on building visions and shaping the future, ensuring every project, whether a CAT A or CAT B, is delivered safely, efficiently, and to the highest professional standards. With over 25 years of expertise in the refurbishment and fit-out of industrial and commercial buildings, including intricate warehouse refurbishments and dilapidations, we guide our clients through every stage, from feasibility to completion. Our goal is to minimise surprises, maximise value, and transform spaces into environments where businesses can truly thrive.

So, what exactly differentiates a CAT A from a CAT B fit-out, and why does this distinction matter for your commercial property aspirations?

Understanding the Foundation: Shell & Core

Before delving into CAT A and CAT B, it's beneficial to briefly touch upon the "Shell & Core" stage. This represents the absolute foundational stage of a building. At this point, the exterior of the property is complete, and the building boasts its core structural elements – think concrete and metal frameworks, external facades, roofing, and essential utilities brought to a central point on each floor. It will also typically include communal areas such as lift shafts, lobbies, and sometimes basic WCs. Essentially, a Shell & Core space is a weatherproofed, structurally sound building, but internally, it is still a bare construction site, devoid of internal partitions, finishes, or dedicated services.

CAT A Fitout: The Blank Canvas

A CAT A fit-out builds directly upon the Shell & Core. It is typically undertaken by landlords or developers, with the primary objective of preparing a commercial space to a basic, functional standard, ready for a prospective tenant to begin their own bespoke customisation. We often describe a CAT A space as a "blank canvas" – it’s clean, functional, and equipped with the fundamental services required for occupation, but it lacks any specific design or layout tailored to an end-user.

The scope of a CAT A fit-out, while not universally standardised, generally includes:

Raised Access Flooring: This creates a void beneath the floor for the installation of essential services like electrical wiring, data cabling, and HVAC (heating, ventilation, and air conditioning) pipework, offering flexibility for future layouts.

Suspended Ceilings: These provide a clean, finished appearance and conceal the building's services running above. Basic lighting is typically installed within these ceilings.

Mechanical & Electrical (M&E) Services: This encompasses the primary distribution of electricity, lighting, and air conditioning systems throughout the floorplate, brought to a reasonable distribution point. While functional, these systems are not typically zoned or tailored to specific office layouts at this stage.

Basic Fire Detection and Alarm Systems: Essential safety systems are installed to meet building regulations.

Wall Finishes: Perimeter walls are usually provided with a basic finish, often painted in a neutral colour.

WCs and Lift Lobbies: Common areas and welfare facilities are generally completed to a functional standard.

From the landlord's perspective, a CAT A fit-out is a strategic investment. It makes the property attractive to a wide range of potential tenants by offering a flexible, ready-to-customise space that requires less upfront investment from the landlord compared to a fully fitted-out office. It also allows for a quicker turnaround time between tenancies. For a tenant, a CAT A space provides the fundamental infrastructure, enabling them to then engage a fit-out specialist, like 4construct, to transform the space into their ideal working environment.

CAT B Fitout: The Bespoke Transformation

Where a CAT A fit-out provides the foundation, a CAT B fit-out is where a space truly comes to life, meticulously tailored to the unique needs, brand identity, and operational requirements of the occupying business. This stage typically follows on directly from a CAT A fit-out and is generally commissioned and funded by the tenant.

At 4construct, our CAT B fit-out services are comprehensive, taking the blank canvas and creating a fully functional, inspiring, and productive workspace. This involves a deep understanding of the client's vision, workflow, and culture. We work in close partnership with our clients, from initial space planning and workplace consultancy to the final installation of every detail.

The elements typically included in a CAT B fit-out are extensive and can vary significantly based on the client's specific requirements, but commonly include:

Internal Partitioning: This is a crucial element, defining the layout of the space by creating individual offices, meeting rooms, boardrooms, quiet zones, breakout areas, and collaborative spaces. We utilise various partitioning systems, including solid, glazed, and acoustic solutions, to optimise functionality and aesthetics.

Specialised Finishes: This is where the individuality of the space truly shines. It includes bespoke flooring (carpets, vinyl, timber, polished concrete), custom wall coverings, decorative lighting fixtures, and tailored ceiling treatments.

Bespoke Joinery: Custom-built reception desks, cabinetry, storage solutions, and kitchen units are designed and installed to meet specific needs and enhance the overall aesthetic.

Kitchens and Tea Points: Fully fitted kitchens, often incorporating modern appliances and bespoke designs, are installed to provide essential staff amenities.

Furniture and Workstations: This involves the procurement and installation of all office furniture, including desks, chairs, ergonomic solutions, seating for breakout areas, and reception furniture.

IT and Audio-Visual Infrastructure: Advanced data cabling, network points, server rooms, Wi-Fi integration, and the installation of audio-visual equipment for meeting rooms and presentation spaces are all critical components.

Brand Integration and Décor: The space is infused with the company's brand identity through custom signage, corporate colours, artwork, and other decorative elements that reflect the organisational culture and values.

Re-routing of M&E Services: The existing CAT A services are often reconfigured and extended to align with the new partition layouts and specific power and data requirements of individual workstations and rooms.

Acoustic Treatments: To enhance comfort and productivity, acoustic panels, sound-absorbing materials, and other solutions are integrated to mitigate noise levels in open-plan areas and ensure privacy in meeting rooms.

A CAT B fit-out is more than just adding furniture; it's about crafting an environment that fosters collaboration, boosts productivity, supports employee wellbeing, and reinforces a company's brand and culture. It's an investment in a tailored workspace that directly impacts operational efficiency and staff satisfaction.

Key Distinctions and Why They Matter

The fundamental difference lies in scope and purpose:

CAT A: Provides a landlord-ready, functional, and aesthetically neutral space. It’s about getting the building ready for the next stage of development.

CAT B: Transforms that functional space into a tenant-specific, fully operational, and branded environment. It’s about creating a truly bespoke workplace.

Who commissions the work?

CAT A: Primarily commissioned by landlords or developers.

CAT B: Primarily commissioned by the tenant.

Cost and Timeframe:

CAT A: Generally less expensive and quicker to complete due to its basic nature.

CAT B: More costly and time-consuming, given the bespoke design, extensive customisation, and often complex integration of services and finishes.

Choosing between a CAT A and CAT B fit-out, or indeed considering a hybrid approach such as a CAT A+ (which offers more landlord-provided amenities than a standard CAT A but less bespoke customisation than a CAT B), depends entirely on your specific needs, budget, and timeline.

At 4construct, we pride ourselves on providing expert advice from the feasibility stage, ensuring you have the insights needed before making costly decisions. We handle every detail, from planning and design to specialist surveys, through to building control and Health & Safety compliance. Whether you require a fundamental CAT A foundation or a complete, bespoke CAT B transformation, our experienced team is equipped to deliver a project that exceeds your expectations, on time and within budget. We don't just construct buildings; we build lasting relationships and workspaces that enable businesses across the UK to thrive.