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The Difference Between Cat A and Cat B Fit-outs

Introduction

Every area of work or industry has its own language, and this can make it very difficult for people to understand and know what is being discussed. The construction and refurbishment industry is no exception.

This article identifies the differences between Commercial Cat A and Cat B fit-outs, so you can be more confident and knowledgeable as to the differences and what each entails.

What is Cat A fit-Out?

Cat A is the very basic fit-out a commercial building undergoes during refurbishment. This is often described as the ‘empty shell’ phase. It typically includes essential elements necessary for occupancy. Therefore, it lacks any specific interior finishes or customisation.

Key features of a Cat A fit-out:
i. Cat A fit-outs include basic services such as electrical, lighting, plumbing, and heating/cooling systems. These services are installed up to a specified point but are not typically tailored to the customer’s needs. If the building is to have a lift, then work will be carried out to ‘house’ the facility at this stage.

ii. The space usually includes raised flooring and a suspended ceiling grid, providing flexibility for future configurations.

iii. Common areas like hallways, staircases, lifts, and toilets are part of Cat A fit-outs.

iv. Fire detection, smoke alarms and suppression systems are installed to meet building regulations.

v. The walls are generally left unfinished or painted in a basic neutral colour. Floor coverings and finishes, such as carpet tiles or concrete screed, may be provided at a basic level.

Cat A fit-outs serve as a starting point for customers, allowing them to customise the space to meet their specific requirements.

Some of our Cat A projects include:

 

What is a Cat B fit-out?

Cat B is all related to fitting out a new or existing office space based on customer requirements and personal choice. Some of the types of work which can be specifically undertaken during a Cat B fit-out are detailed below:-

Key features of a Cat B fit-out:
i. Designing the layout, installing internal partitions, and creating individual offices, meeting rooms, open workspaces, reception areas, and any other required spaces. The design and materials are very often tailored to meet specific branding and functional requirements.

ii. The base building services provided in the Cat A fit-out may be modified or expanded to align with the customer’s specific needs. This includes electrical layouts, data cabling, HVAC zoning, and other services required for the customer’s operations.

iii. Cat B fit-outs include a wide range of finishes such as specific flooring materials, wall finishes, tailored ceiling treatments, lighting fixtures, and special fixtures and fittings.

iv. The customer is responsible for providing furniture, workstations, office equipment, and any other items required for their day-to-day operations.

Summary of Cat A and Cat B Fit-Outs
Cat B provides a ready-to-occupy space with the desired aesthetics, functionality, and branding. These are the ones which most people are familiar with and certainly something that everyone can relate to. Generally speaking, Cat B fit-outs are everything that Cat A fit-outs are not, but it is far more than this. If you imagine that with a Cat A fit-out, the blank canvas has been completed and the ‘foundations’ of the structure have been set. Cat B then is moving this along to include the fitting of the fabric of the building or space. A good and alternative way to imagine this is to think when you relocate offices and the place is completely new and empty, with just the office space in its existing form. You could then come along and install partitioning, flooring, IT, service infrastructure and other decorations to develop your office requirements and place your own corporate branding. This is essentially what Cat B fit-outs are.

Some of our Cat B projects include:

For more information:
To find out more on this topic, visit our interior fit-out section, or if you need more particular information read our Cat A or Cat B pages.

If you have a Cat A or Cat B question or project in mind, please contact our regional specialists via our Contact Us page.

Joe Gallagher

With 19 years of experience and over 500,000 square ft of CAT B office fit-outs delivered in London’s most prestigious locations, Joe Gallagher is our CAT B fit-out project lead. His portfolio reflects over £110 million worth of commercial office fit-outs for customers ranging from banks, media brands, and tech companies to developers and management consultants.

Learning and Development

We believe continued learning and development is crucial to our team’s everyday needs. Our internal L&D system, Willmott Dixon University, supports a wide range of courses for all of our people to ensure they are best-equipped to perform well in their job roles.

We are able to offer unlimited opportunities to those with the ambition to take their career to the next level and work in a stimulating environment. By offering 4 levels of management development programmes, we are able to provide the skills you need to help reach your potential.

Pension and Life Assurance

We strongly value your future and want to help you save for it, that is why we will contribute by 6% of your pension and you will be protected by Willmott Dixon Interiors Life Assurance Scheme (more details to come when joining).

Flexible Working & More

The best is yet to come! We give you a day off for your birthday (without using your holiday entitlement), early leave every Friday, dress down Friday once a month, Summer and Christmas events, and more. We have ambitions to be an employer of choice for those who either want to or need to work in a flexible and agile way. Experience it all when joining our team, we are looking forward to getting to know you.

Salary and Profit Share

At Willmott Dixon Interiors we are proud of our people and sincerely believe that our success depends on them and their skills. We reflect our gratitude in the highly competitive salary we offer and review every year. In addition, we will thank you for your hard work with the percentage of our annual profit (subject to certain criteria) to the scope of reflecting our ‘one team’ nature.

Private Health Care

We value your health care and wellbeing and that is why we offer free or discounted private health care that will avoid you NHS long waiting lists.

Loyalty Rewards

After five years with us, you’ll join our 5-9 Year Club and celebrate annually with the other members. After reaching 10 years, you will join the prestigious Willmott Dixon 10 Year Club and celebrate along with Rick Willmott.

Work Experience

We are supported by a trusted supply chain, guaranteeing the use of high-quality materials, and ensuring timely project execution. Our long-standing relationships allow us to deliver excellence on every project.

Technical Apprentice Programme

Apprenticeships are a great route into construction. At Willmott Dixon, apprenticeships are available in our business support teams and also through our supply chain partners or our sister company, Fortem, in trade disciplines such as bricklaying.

We offer some entry level positions for those who are looking to take their first steps into construction. With a paid apprenticeship you will earn while you learn and obtain a Level 3 qualification. You can apply following GCSEs; you don’t to have a construction background to complete an apprenticeship.

Management Development

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Professional Qualifications

We believe that our teams should continue to have ongoing development both in and out of construction and are committed to assisting them in becoming qualified within a professional qualification of their choice.

A HERITAGE OF TRUST AND RELIABILITY

Backed by over 172 years of success, Willmott Dixon Interiors is part of one of the UK’s most established construction companies. Our long-standing reputation means you can trust us to deliver with the highest standards of quality, and that you are partnering with a company that is secure and dependable, especially in an industry where financial stability is crucial for project success.

Why we do it

By keeping buildings alive, we preserve their history while ensuring they remain relevant, sustainable, and functional in a changing world. Our work is about more than just refurbishment—it’s about creating spaces that inspire, support communities, and provide lasting value.

Let’s work together to transform spaces, ensuring they stand the test of time while meeting the needs of today and the future.

TRANSPARENT AND RELIABLE PROJECT MANAGEMENT

We prioritise on-time and within-budget delivery. Our clear communication and proactive approach ensure that you stay informed throughout the project, giving you peace of mind from start to finish.

PROVEN EXPERTISE

With extensive experience in the commercial fit-out market, we understand how to deliver projects that meet your unique needs. Our team has completed a wide range of traditional and design & build, high-quality fit-outs across multiple sectors.

SEAMLESS DESIGN AND BUILD DELIVERY

If required our integrated design and build services can streamline the process from RIBA Stage 2 or 3 to completion, saving you time and effort. With in-house design capabilities and relationships with external design partners across all disciplines it gives us full flexibility to develop a tailored approach for each project.

COMMITMENT TO LONG-TERM PARTNERSHIPS

We believe in building relationships based on trust, performance, and transparent communication. Our goal is to create long term partners, ensuring that every project we deliver contributes to your ongoing success.

SUSTAINABILITY

Our dedicated in-house team ensures that every project aligns with our ambitious sustainability goals. As a business, we are committed to achieving a net-zero status by 2030, and we hold ourselves accountable at every stage of our operations. From minimising waste through innovative recycling programs to selecting sustainable materials and incorporating energy-efficient practices, we focus on reducing environmental impact.

ATTENTION TO DETAIL

From our appointment to the final handover, we focus on creating office environments that not only meet but exceed your expectations. Our attention to detail ensures that your space is functional, beautiful, and aligned with your business goals.

TRUSTED TEAM AND SUPPLY CHAIN

We are supported by a trusted supply chain, guaranteeing the use of high-quality materials, and ensuring timely project execution. Our long-standing relationships allow us to deliver excellence on every project.

How we work

Our process

What we do

We specialise in the fit-out and refurbishment of buildings across multiple sectors, from offices and healthcare facilities to hotels, retail, and secure environments. Whether it’s breathing new life into a heritage building, modernising commercial spaces, or ensuring critical environments remain fully operational during works, we are committed to delivering projects with precision and care.

Key areas of focus:

A trusted team and supply chain: Our people are what make us stand out. From project managers to site teams, we bring a wealth of experience and a proactive approach to every project. We also support our supply chain partners with a 28-day payment term and a commitment to fair treatment, ensuring high-quality materials and timely execution.

Seamless design and build delivery: If required, our integrated design and build services streamline the process from RIBA Stage 2 or 3 to completion, saving you time and effort.

Live environment expertise: We excel in delivering projects in occupied and secure environments with minimal disruption, ensuring business continuity and safety.

Long-Term partnerships: We believe in building relationships based on trust, performance, and transparent communication, ensuring every project we deliver contributes to your ongoing success. Many of our customers return to us time and time again, a testament to our commitment to quality and service.

Attention to detail: From appointment to final handover, we focus on creating environments that not only meet but exceed expectations. Our rigorous quality assurance processes ensure every element of a project is delivered with precision.

Sustainable refurbishments: We pledge to be net-zero operational carbon by 2030 and have a net-zero supply chain by 2040. Our projects focus on energy efficiency, waste reduction, and the use of sustainable materials.

How we do it

A heritage of trust and reliability: With over 172 years of success, Willmott Dixon Interiors is part of one of the UK’s most established construction companies. Our long-standing reputation means you can trust us to deliver with the highest standards of quality, and that you are partnering with a company that is secure and dependable, especially in an industry where financial stability is crucial for project success.

Transparent and reliable project management: We prioritise on-time and within-budget delivery. Our clear communication and proactive approach ensure that you stay informed throughout the project, giving you peace of mind from start to finish.

End-to-end project management: From feasibility studies to design and delivery, our expertise ensures projects run smoothly, on time, and within budget.

Expert procurement support: We simplify the tender process and guide customers through procurement frameworks, ensuring compliance and efficiency.

Sustainability-focused solutions: With a dedicated in-house team, we align every project with our ambitious sustainability goals, minimising waste and integrating energy-efficient solutions.

 

Holidays

We commit everyday to promoting a healthy work/life balance that matches a competitive holiday allowance, the longer you stay the more you get. 

If the holidays allowance isn’t enough, you can take advantage of buying extra holiday entitlement each year.