Cat A and Cat B Office Fit Out: What’s the Difference?

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Understanding the difference between Cat A and Cat B office fit out is essential if you are planning a new workspace or refurbishment in London. These terms define how far the space has been taken, who is responsible for the work, and how your budget, timeline and obligations are structured.​

Whether you are a landlord preparing a floor for market or a tenant looking for a fully branded space ready for day‑one use, knowing where Cat A ends and Cat B begins will help you brief the right office fit out company London and avoid surprises later.​

What is a Cat A office fit out?

A Cat A office fit out is typically provided by the landlord or developer to create a clean, compliant and lettable “blank canvas” for incoming tenants. It turns a shell and core or basic structure into a usable, open‑plan environment with core services in place but no tenant‑specific layouts or finishes.​

Typical Cat A features often include raised access floors, suspended ceilings, base HVAC, general and emergency lighting, fire detection and alarms, basic decorations to perimeter and core walls, and completed common areas. The space is usually neutral and uncluttered, allowing tenants and their chosen office fit out companies London to visualise how they might occupy and personalise it.​

Who delivers and pays for Cat A?

In almost all cases, the landlord or property developer funds and manages the Cat A office fit out as part of their investment in the building. The goal is to create a marketable, regulation‑compliant unit that agents can show to multiple potential occupiers without committing to any one tenant’s layout or brand.​

Because Cat A is landlord‑led, it sits outside the tenant’s fit out budget, although the cost is effectively recovered through rent over the term of the lease. Landlords often work with experienced office fit out company London specialists to ensure the specification meets current expectations for energy efficiency, sustainability and flexibility while aligning with their overall asset strategy.​

What is a Cat B office fit out?

A Cat B office fit out is the tenant’s stage. It takes the Cat A “blank canvas” (or in some cases a shell and core) and turns it into a fully functioning, branded workspace tailored to specific teams, workflows and culture. This covers everything from space planning and internal partitions through to finishes, furniture, technology and graphics.​

Typical Cat B elements include layouts for desks, collaboration zones and quiet rooms, meeting suites and boardrooms, receptions, staff kitchens and tea points, specialist areas such as labs or studios, detailed M&E modifications, all floor and wall finishes, corporate branding, audiovisual systems and complete furniture provision. It is this phase that really distinguishes one office refurbishment London project from another.​

Who delivers and pays for Cat B?

Cat B is almost always the responsibility of the incoming tenant, who funds and commissions the work to match their operational requirements and brand. Many businesses choose a design‑and‑build route, appointing one of the established office fit out companies London to handle design, approvals, construction and move‑in under a single point of responsibility.​

Because Cat B is a direct investment in the tenant’s own environment, it is typically more variable in cost than Cat A, depending on project size, specification level, technology, furniture and density. Where market conditions allow, landlords may offer incentives such as capital contributions or rent‑free periods to support Cat B spend, which an experienced office fit out company London can help you negotiate and structure effectively.​

Cat A vs Cat B: key differences at a glance

Cat A and Cat B differ in purpose, scope, responsibility and outcome:

• Purpose: Cat A makes the space compliant and lettable; Cat B makes it operational, branded and tailored to a specific tenant.​
• Responsible party: Cat A is typically delivered by the landlord or developer; Cat B is driven and funded by the tenant.
• Scope: Cat A covers base services, neutral finishes and common areas; Cat B covers partitions, detailed M&E, finishes, furniture, technology and graphics.
• Customisation: Cat A is deliberately generic, while Cat B is highly bespoke and aligned with the tenant’s brand and ways of working.
• Completion state: A Cat A space is ready for design; a completed Cat B workspace is ready for occupation with staff able to work from day one.​

Many landlords are now also offering “Cat A+” schemes that add simple meeting rooms, kitchens and basic furniture to a Cat A specification, effectively providing a light Cat B solution aimed at quicker occupation. Deciding whether Cat A, Cat A+ or a full Cat B office refurbishment London route is best will depend on your timeframe, budget and appetite for customisation.​

How Cat A and Cat B affect your lease and dilapidations

The distinction between Cat A and Cat B is not just technical; it also affects your lease obligations and exit costs. The lease will usually define the landlord’s Cat A obligations and the tenant’s rights to carry out Cat B works, often via a licence to alter.​

At lease end, many tenants are required to strip out their Cat B works and return the space to an agreed condition, which is usually Cat A or similar. This “dilapidations” obligation can be significant, so it is wise to plan Cat B with future reinstatement in mind and to work with office refurbisment companies London who understand how design decisions today can impact reinstatement complexity and cost tomorrow.​

Compliance, health and safety and accreditations

Both Cat A and Cat B office fit outs must comply with UK Building Regulations, fire safety standards, CDM Regulations and relevant British Standards. In practice, landlords focus on base‑build compliance at Cat A, while tenants and their contractors must ensure Cat B changes maintain or enhance that compliance.​

Prestige Interiors’ accreditations, including CHAS, SafeContractor and NICEIC registration, along with recognised waste‑carrier status, support robust health and safety, electrical safety and responsible waste management across Cat A and Cat B projects. This gives reassurance to landlords, managing agents and tenants alike that works will be delivered safely, legally and with appropriate environmental care. As a business owned by two women in a traditionally male‑dominated sector, Prestige also maintains strong equal opportunities and ethical standards across its operations.​

When to focus on Cat A, Cat B or both

The right emphasis depends on your role and objectives:

• Landlords and developers:
  • Prioritise high‑quality, flexible Cat A or Cat A+ specifications that meet modern expectations for sustainability, wellness and technology readiness.​
  • Work with an office fit out company London that understands leasing strategies and what London occupiers are looking for in terms of services, floor plates and amenities.​
• Tenants planning a move or refurbishment:
  • Focus on Cat B, but make sure you fully understand the existing Cat A provision, any limits in the base services and your obligations under the lease.
  • A tenant‑side adviser or design‑and‑build team from one of the established office fit out companies London can help you review the landlord’s Cat A pack, test different layouts and build a realistic Cat B scope and budget before you sign.​
• Businesses refreshing an existing space:
  • You may already occupy a Cat B environment but need to re‑plan, rebrand or support new ways of working, such as hybrid or activity‑based models.​
  • In these scenarios, a targeted office refurbishment London approach can upgrade the existing Cat B fit out without returning all the way to Cat A, saving both time and cost.

How Prestige Interiors supports Cat A and Cat B projects

Prestige Interiors works on both sides of the Cat A/Cat B line, supporting landlords, managing agents and occupier clients across London and the South East. For landlords, the team can design and deliver Cat A or Cat A+ schemes that are efficient to build, easy to let and aligned with their long‑term asset strategy.​

For tenants, Prestige provides a full design‑and‑build service for Cat B, from initial brief and space planning through to construction, furniture installation and move‑in support. With deep experience across sectors and building types, and a strong focus on compliance, communication and programme control, the practice stands out among office fit out companies London for its ability to manage complex transformations with minimal disruption.​

FAQs

Is Cat A or Cat B more expensive?

Cat A is usually less expensive per square foot than a full Cat B office fit out, because it stops at base services and neutral finishes. Cat B typically carries higher upfront costs as it includes layouts, all finishes, furniture and technology, but it also delivers a complete, ready‑to‑use workplace tailored to your business.​

Can we move straight into a Cat A space?

You can sign a lease on a Cat A office, but you cannot realistically move staff in until Cat B works are complete. Cat A spaces lack partitions, full furniture, detailed IT and AV and brand‑specific elements, so a Cat B phase is still required before the office is operational.​

What is Cat A+ and how does it fit in?

Cat A+ is an enhanced Cat A offer where the landlord adds simple meeting rooms, a tea point, some basic furniture and data points so the space feels more “plug‑and‑play”. It can shorten time to occupation and reduce initial Cat B spend, but it offers less freedom than starting from a pure Cat A shell.​

Do we always have to strip out our Cat B at the end of the lease?

Not always, but it is a common requirement. The lease and any licence to alter will set out your dilapidations obligations, which may include removing partitions, kitchens and tenant‑installed services to return the space to Cat A or another agreed condition. Good office refurbisment companies London will design and document works so future reinstatement is understood from the outset.​

How do we decide whether to prioritise Cat A or Cat B in our negotiations?

If you are a tenant, you will almost always derive more day‑to‑day value from Cat B, as this is what your staff actually experience. However, in a competitive market it can be advantageous to negotiate both a high‑quality Cat A baseline and meaningful Cat B incentives. An experienced office fit out company London or tenant adviser can help you model different scenarios and choose the option that best supports your budget, timing and workplace strategy.​

Conclusion and next steps

Cat A and Cat B are more than technical labels: they shape who does what, who pays, how long your project will take and what your teams walk into on day one. If you are comparing buildings, planning a move or considering a refresh, having a clear view of both stages will make your decisions on scope, budget and programme much more robust.​

When you are ready to explore specific options for your next London workspace, from base‑build upgrades through to fully bespoke tenant environments, your next step is to review the office fit out London hub content. This will show how Prestige Interiors applies Cat A and Cat B thinking across live projects and how the team can support your own transformation from first brief to final handover.