Category A and Category B fit outs might sound similar but when it comes to office fit outs, they’re worlds apart.
The problem is that there’s still no standard industry definition for the terms. This means researching your own office refurbishment or relocation project can become a little confusing - not to mention costly. Crucially, both the work involved and the outcome of these commercial projects vary considerably. That’s why it’s vital to understand the difference, so you can get things right the first time. But before delving into the difference between category A and category B fit-outs, there’s something else we should cover first: shell and core.
What is a shell and core fit-out?
OK, it makes sense to start here because a shell and core fit-out covers the bare bones of a building. The office may look complete from the outside but it’ll be an empty shell internally.
That’s not to say the core amenities won’t be included; it’s just that this space is unlikely to have any level of polish or finish to it (that comes later).
What’s included in a shell and core fit-out?
Essentially, shell and core fit-outs will include the basics a building needs to function. This includes:
- The building’s fabric and structure, e.g. walls, roof, windows and floor.
- Its core services, e.g. centralised mechanics and electrics (heating, cooling and ventilation)
- Localised services, e.g. lighting, local heating, cooling and ventilation.
But some shell and core fit-outs also include some completed communal areas, e.g. building reception, lifts and toilets.
The positive about working on a shell and core fit-out is that there are plenty of opportunities to make the space as sustainable as possible from the offset. This is more important than ever considering the construction sector’s greenhouse gas (GHG) emissions make up approximately 40% of global GHG emissions.
So how can shell and core fit-outs be sustainable?
By adhering to the Leadership in Energy and Environmental Design certification (LEED) -the most widely used green building rating system in the world.
LEED for Shell and Core
LEED is a green building system that provides a set of sustainable design and construction standards for shell and core buildings. It promotes practices to ensure buildings are as environmentally-friendly as possible. Gaining certification from LEED also helps to create a sustainable workplace and puts you on the right path toward net-zero carbon (NZC).
For further actionable steps to reach NZC download our free guide where you’ll find more guidance and advice.
So, we now know that shell and core fit-outs cover the essentials, but what about categories A and B?
Now we know about shell and core fit outs, let’s look at the difference between Cat A and Cat B fit outs?
What is a category A fit-out?
Category (Cat) A fit-outs are usually carried out for a landlord, institutional investor or developer. The main objective for this type of fit-out is to prepare a building so that it's ready for an end-user client (who’s generally the tenant). The tenant can then go in and work with their own design and fit-out partner to create a bespoke workplace solution.
What’s included in a category A fit-out?
A standard category A fit-out can include:
- Standard finishes to the floors, walls and ceilings
- Basic mechanical and electrical services
- Fire detection services and smoke alarms
- Air-conditioning and ventilation (HVAC)
- Fundamental internal finishes
- Lifts, toilets and shower facilities
- The lobby and reception area
Essentially, the space is finished but with no fixtures, fittings or furnishes. Instead, the office space is functional - without the bells and whistles like partitions, meeting rooms, individual office spaces or bespoke branding.
Don’t forget Category A+ fit outs
We’ll get to Cat B fit outs shortly. But first, there’s a relatively new concept that bridges the gap between the two: the category A+ fit-out.

What is category A+ fit-out (Plug and Play)?
Category A+ (often referred to as ‘Plug and Play’) is defined as the line between a category A and category B fit-out. It serves as the mid-point where the landlord appoints more practical design features that will make the space ready for occupation immediately.
What’s included in a category A+ fit-out?
Usually, mechanical, electrical and safety features will all be in place. These can include:
- Electrical outlets
- Heating and air conditioning
- Toilets
- Raised access floors
- Suspended ceilings
- Fire protection systems
- Basic furnishings and some decorative features
But to make things even more attractive to potential occupiers, some landlords take things even further. Some category A+ fit-outs can also include:
- Boardrooms
- Comms rooms (complete with data cabling)
- Fully furnished suites
- Tea points, break rooms and other facilities
Category A+ offices are an enticing option for the modern workforce and provide a number of benefits post-pandemic.
What are the benefits of category A+ fit-outs?
Although many organisations have returned to the office, the needs of their occupants have evolved. But this approach not only benefits employees seeking a more flexible work environment; it can work well for employers and landlords too. The benefits of category A+ fit-outs include:
- A modern space that’s more marketable compared to category A fit-outs
- An office that takes less time for tenants to move in as facilities are already in place
- Reduced upfront costs for tenants renting the space
- Increased flexibility in terms of lease terms and contract lengths
- More enticing spaces for employees who are considering returning to work
- ‘Plug and Play’ nature and flexible lease agreements make it ideal for hybrid and communal co-working spaces
- Tech-savvy startups can occupy quickly with the space they need to grow
As you can see, this type of fit-out is attractive for a variety of reasons - but what about category B?

What is a category B fit-out?
OK, so category A+ fit-outs have all the elements of category A - plus some additional features you'd find in a category B install. But although the other two are functional, category B fit-outs are basically the finished article. This completed product is enticing because it presents a ‘ready to work’ concept. So in theory, tenants can move straight in and start their operations.
So, who does the work?
Revitalising a building’s internal space, category B fit-outs are usually carried out:
- in partnership with a professional team
- directly with the occupier to design and create their bespoke workplace solution
And that’s the bonus part of category B fit-outs. Because whether it’s a refurbishment or relocation, these projects will always consider a client’s business objectives, culture and people. In fact, popular workplace requirements such as staff wellbeing facilities, collaboration and improved productivity can all be enhanced through a category B fit-out. That’s because they often include installations of meeting and breakout areas, catering facilities and a variety of working platforms.
What is included in category B fit-out?
As standard, category B fit-outs usually include the following:
- Fully fitted kitchens and non-communal staff facilities
- Partitionings (including meeting rooms, offices and breakout spaces)
- Installed IT infrastructure and workstations
- All soft furnishings
- Air-conditioning, heating and power points
Injecting personality into the space, a category B fit-out will also consider and implement the right branding and finishing options to reflect a business' individual personality and culture - great for staff and visiting clients.
So, what can you expect from the end result?
An attractive and fully-functional working environment; one which supports your current needs and any aspirational goals for the future.

Summary of the differences between a Cat A and Cat B Fit Out
To summarise, the main objective of a Cat A fit out is to prepare a building so that it's ready for an end-user client e.g. a tenant. The tenant can then go in and work with their own design and fit-out partner to create a bespoke workplace solution.
WhereasWhere as a Cat B fit out is the finished article. The completed product presents a ‘ready to work’ concept, so a tenant can move straight in and start their operations.
Want to see for yourself? You can find a variety of category A, category A+ and category B projects in our case studies.
Want to chat about any of the fit-outs in this article? Get in touch, we’d love to hear from you.