Back to Archive Cat A vs Cat B Office Fit Outs: What’s the Difference? (Complete UK Guide) Understanding the difference between Cat A and Cat B fit outs can feel like navigating a maze — especially when everyone seems to define things slightly differently. At TB Fit Out, we break it down in a way that makes sense — no jargon, just the insights you need to plan, budget and deliver your refurbishment project. In this guide, we clearly explain Cat A, Cat A+ and Cat B fit outs, what each includes, who delivers them, typical costs and timelines, and how to decide which option is right for your business. Book Your Workspace Audit What Is an Office Fit Out? An office fit out refers to the process of making an internal commercial space ready for occupation. It typically follows the base building or “shell & core” stage and can range from installing basic services to creating a fully branded, operational workplace. In the UK, office fit outs are usually delivered in stages: Shell & Core Cat A Cat A+ (Plug & Play) Cat B Each stage adds increasing levels of functionality and customisation. What Is a Cat A Office Fit Out? A Cat A fit out provides a functional but neutral office space, usually delivered by the landlord. It creates a blank canvas that allows incoming tenants to complete their own fit out without major building works. Typical Cat A Fit Out Inclusions Raised access floors Suspended ceilings Basic lighting Heating, ventilation and air conditioning (HVAC) Electrical and mechanical services Fire detection and life safety systems Toilets and basic finishes A Cat A space is operationally compliant but not ready for occupation without further work. What Is a Cat B Office Fit Out? A Cat B fit out transforms a Cat A space into a fully functional, bespoke workplace tailored to the tenant’s brand, culture and operational needs. This stage is almost always delivered by the tenant. Typical Cat B Fit Out Inclusions Space planning and workplace design Partitioning and meeting rooms Kitchens and breakout areas Reception and waiting areas Bespoke lighting design Data and IT infrastructure Furniture installation Branding, finishes and décor Acoustic treatments A Cat B fit out results in a move-in-ready office designed specifically for how the organisation works. What Is a Cat A+ (Plug & Play) Fit Out? A Cat A+ fit out, sometimes called plug-and-play, sits between Cat A and Cat B. It is typically landlord-led but includes additional features to reduce tenant fit-out time and cost. Cat A+ Usually Includes: Pre-installed meeting rooms Kitchenettes or tea points Feature lighting Furniture (sometimes optional) Neutral but higher-quality finishes Cat A+ spaces appeal to tenants looking for speed, flexibility and reduced upfront investment. Cat A vs Cat B Fit Out: Key Differences Aspect Cat A Fit Out Cat B Fit Out Delivered by Landlord Tenant Purpose Functional base build Fully operational workspace Design Neutral Bespoke & branded Ready to occupy ❌ No ✅ Yes Cost responsibility Landlord Tenant Timescale Shorter Longer Who Pays for Cat A and Cat B Fit Outs? Cat A: Paid for by the landlord as part of the lease agreement. Cat B: Paid for by the tenant, often using a capital budget or landlord contribution. Cat A+: Usually funded by the landlord to increase market appeal. Understanding this distinction is vital when negotiating leases and planning budgets. How Long Does a Cat A or Cat B Fit Out Take? Timelines vary depending on size and complexity, but typical UK averages are: Cat A fit out: Around 4–8 weeks Cat B fit out: Around 8–16+ weeks Cat B projects involve more design coordination, approvals and specialist installations, which increases programme length. How to Choose Between Cat A and Cat B Fit Out Ask yourself: Do you need a branded, culture-driven workspace? How quickly do you need to occupy the space? What budget and lease incentives are available? Will your space need flexibility in the future? For most organisations, Cat B is essential to create a productive, compliant and engaging workplace. Can a Cat A Space Be Converted to Cat B Later? Yes — in fact, this is the most common approach. A Cat A fit out provides the technical foundation, while the Cat B fit out delivers the final layer of functionality and identity. Frequently Asked Questions What is the difference between Cat A and Cat B office fit outs? Cat A provides basic services and finishes, while Cat B includes layout, furniture, branding and operational elements. What does Cat A+ mean? Cat A+ is a landlord-provided space that includes additional features like meeting rooms and kitchens, reducing tenant fit-out needs. Is Cat B fit out compulsory? While not legally compulsory, most businesses require Cat B works to operate effectively. How much does a Cat B fit out cost? Costs vary widely depending on specification, size and location, but Cat B fit outs represent the largest investment in office refurbishment projects. Why Understanding Cat A vs Cat B Matters Choosing the right fit-out strategy affects: Project cost Programme length Lease negotiations Employee experience Long-term flexibility Clear understanding helps avoid delays, overspend and operational compromises. Book Your Workplace Audit Final Thoughts Whether you’re refurbishing an existing space or moving into new premises, understanding Cat A, Cat A+ and Cat B fit outs helps you plan smarter, negotiate better and deliver on time. For deeper planning and tools, don’t forget our Refurbishment eGuide— it’s packed with templates, timelines and pro tips from the TB Fit Out Team as well as our downloadable Cat A and Cat B Checklist. We are industry experts with over 20 years of experience in office design, refurbishment and fit out specialists working within London, Surrey, Sussex and the South East. Email us at sales@tbfitout.co.uk or call us directly on 01293 775509 and see how we can help you with your next project. You may also like Office Design Trends for 2026: Creating Workplaces That Truly Work Read more How to Design a Workplace That Works for Every Generation Read more Smart Space Planning for Hybrid Workplaces: A Practical Guide for Modern Office Fit-Outs Read more
In this guide, we clearly explain Cat A, Cat A+ and Cat B fit outs, what each includes, who delivers them, typical costs and timelines, and how to decide which option is right for your business. Book Your Workspace Audit What Is an Office Fit Out? An office fit out refers to the process of making an internal commercial space ready for occupation. It typically follows the base building or “shell & core” stage and can range from installing basic services to creating a fully branded, operational workplace. In the UK, office fit outs are usually delivered in stages: Shell & Core Cat A Cat A+ (Plug & Play) Cat B Each stage adds increasing levels of functionality and customisation. What Is a Cat A Office Fit Out? A Cat A fit out provides a functional but neutral office space, usually delivered by the landlord. It creates a blank canvas that allows incoming tenants to complete their own fit out without major building works. Typical Cat A Fit Out Inclusions Raised access floors Suspended ceilings Basic lighting Heating, ventilation and air conditioning (HVAC) Electrical and mechanical services Fire detection and life safety systems Toilets and basic finishes A Cat A space is operationally compliant but not ready for occupation without further work. What Is a Cat B Office Fit Out? A Cat B fit out transforms a Cat A space into a fully functional, bespoke workplace tailored to the tenant’s brand, culture and operational needs. This stage is almost always delivered by the tenant. Typical Cat B Fit Out Inclusions Space planning and workplace design Partitioning and meeting rooms Kitchens and breakout areas Reception and waiting areas Bespoke lighting design Data and IT infrastructure Furniture installation Branding, finishes and décor Acoustic treatments A Cat B fit out results in a move-in-ready office designed specifically for how the organisation works. What Is a Cat A+ (Plug & Play) Fit Out? A Cat A+ fit out, sometimes called plug-and-play, sits between Cat A and Cat B. It is typically landlord-led but includes additional features to reduce tenant fit-out time and cost. Cat A+ Usually Includes: Pre-installed meeting rooms Kitchenettes or tea points Feature lighting Furniture (sometimes optional) Neutral but higher-quality finishes Cat A+ spaces appeal to tenants looking for speed, flexibility and reduced upfront investment. Cat A vs Cat B Fit Out: Key Differences Aspect Cat A Fit Out Cat B Fit Out Delivered by Landlord Tenant Purpose Functional base build Fully operational workspace Design Neutral Bespoke & branded Ready to occupy ❌ No ✅ Yes Cost responsibility Landlord Tenant Timescale Shorter Longer Who Pays for Cat A and Cat B Fit Outs? Cat A: Paid for by the landlord as part of the lease agreement. Cat B: Paid for by the tenant, often using a capital budget or landlord contribution. Cat A+: Usually funded by the landlord to increase market appeal. Understanding this distinction is vital when negotiating leases and planning budgets. How Long Does a Cat A or Cat B Fit Out Take? Timelines vary depending on size and complexity, but typical UK averages are: Cat A fit out: Around 4–8 weeks Cat B fit out: Around 8–16+ weeks Cat B projects involve more design coordination, approvals and specialist installations, which increases programme length. How to Choose Between Cat A and Cat B Fit Out Ask yourself: Do you need a branded, culture-driven workspace? How quickly do you need to occupy the space? What budget and lease incentives are available? Will your space need flexibility in the future? For most organisations, Cat B is essential to create a productive, compliant and engaging workplace. Can a Cat A Space Be Converted to Cat B Later? Yes — in fact, this is the most common approach. A Cat A fit out provides the technical foundation, while the Cat B fit out delivers the final layer of functionality and identity. Frequently Asked Questions What is the difference between Cat A and Cat B office fit outs? Cat A provides basic services and finishes, while Cat B includes layout, furniture, branding and operational elements. What does Cat A+ mean? Cat A+ is a landlord-provided space that includes additional features like meeting rooms and kitchens, reducing tenant fit-out needs. Is Cat B fit out compulsory? While not legally compulsory, most businesses require Cat B works to operate effectively. How much does a Cat B fit out cost? Costs vary widely depending on specification, size and location, but Cat B fit outs represent the largest investment in office refurbishment projects. Why Understanding Cat A vs Cat B Matters Choosing the right fit-out strategy affects: Project cost Programme length Lease negotiations Employee experience Long-term flexibility Clear understanding helps avoid delays, overspend and operational compromises.
Book Your Workplace Audit Final Thoughts Whether you’re refurbishing an existing space or moving into new premises, understanding Cat A, Cat A+ and Cat B fit outs helps you plan smarter, negotiate better and deliver on time. For deeper planning and tools, don’t forget our Refurbishment eGuide— it’s packed with templates, timelines and pro tips from the TB Fit Out Team as well as our downloadable Cat A and Cat B Checklist.