What is the difference between Cat A & Cat B fit Outs?

What is the difference between Cat A & Cat B fit Outs?



There is no universal or absolute definition of ‘Shell and Core’, ‘Category A’ or ‘Category B’ fit outs. However the following definitions describe what can be assumed to be included:

Shell and Core

The building is completed to the following specification: Complete fit out of reception / entrance halls, staircases, communal areas, toilets, lifts and core. To include Base Services’ plant and equipment terminated at breakout points to floors. Basic safety infrastructure – sprinkler systems, tanks and risers, fire alarm panel and emergency standby generator.

The above Shell & Core works are usually completed before Select Interiors are employed

Images demonstrate a Cat A & B fit out for client project Brunel. Select Interiors carried out high specification joinery, finishing and management works on this project.  Managing Director Carl Brown was heavily involved with the design direction along with his operations and makers team to complete the office to a high end standard.


Shell and core example prior to Select Interiors work commencement

cat a and b fit out office

Image demonstrates the transformation following Select Interiors extensive work

Cat A Fit Out

Category ‘A’ (also known as Developer’s Fit out)

These works include the completion of the base building works to the shell and core. Works also usually include a level of fitting out between the shell and core to the point at which internal components must be designed to a specification for the end user, (known as Category ‘B’).

Category A Fitting out elements will usually include: Suspended ceilings, raised floors, basic mechanical and electrical services – lighting, heating, ventilation, cooling and associated control systems. All wall and floor finishes to cores, fully fitted out WCs; sprinklers, fire alarms, safety signage and distributed power small power to each floor

During works

Completed Cat A fit out for Colas Rails & Bruntwood Properties Ltd included, cleaner’s sockets small power, lighting, suspended ceilings, ventilation, decoration and flooring
The base structure was dilapidated and required a whole infrastructure for mechanical & electrical services as well as external walls between existing glazing. The works were undertaken over a 6-week programme for the Landlord 
Select Interiors won this project for the Cat B fit out and were awarded another HQ for Colas Rail in York
Please see below for more photographs of the completed Cat B fit out works for Colas Rail 

Cat B Fit Out

These works generally follow completion of Category ‘A’ works, but can be incorporated into a Category ‘A’ construction programme as the example above on the 10th floor at City Tower. This can reduce costs and construction time by avoiding duplication of materials, handling & preliminaries

Category B Fitting out elements will usually include: suspended ceiling upgrades and modifications, internal partitioning, floor finishes (other than office carpet). Completion of mechanical and electrical services to tenant’s specification. Specific items of systems plant and equipment – ventilation and lighting to suit tenant’s requirements. Alterations to raised access floors, installation of containment, small power and data cabling. Reconfiguration of Cat A fire strategy and emergency lighting if sub dividing space by the addition of partitions, offices and boardroom areas to conform to Building Regulations. Decoration and branding, furniture, storage, fixtures and office equipment.

See the full set of completion images and case study of the office CAT A & B scheme on the 6th Floor of the Iconic City Tower which is located in Piccadilly, Manchester City Centre.
There are many elements to a Cat B fit out and some of the Cat A fit out elements are altered to suit the revised layout as on the scheme illustrated for Bruntwood Properties & Colas Rail.
cat b fit out costs guide

The above Pie Chart illustrates the breakdown percentage of total budget for the Cat B fit out as photograph above the chart

Cat B office fit out Manchester

Completion of Colas Rail Cat B works by Select Interiors

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Considerations and Breakdown of elements required for CAT A & B Fit out. 

Site Manager & Gantt Chart Programme

Having a site manager appointed to your project will ensure a smooth, seamless and safe journey for the contractors and client. Delivering the project on time (following Gantt Chart Programme) and on budget is also a huge benefit to all.

Professional Fees

The fees include design drawings, electrical, mechanical, fire strategy drawings. The location plan, sub consultants fees including Electrical & Mechanical Engineers, CDM Coordinators, Building Control plan check and disbursements Plus site management for the 4 week programme, waste removal, general overheads, preparing Health, Safety and Operational Manuals – 10% of contract value of £150,000.00

Many business owners like the simplicity of dealing with only one company. There is a reduced chance of miscommunication & misunderstandings. This speeds things up and results in less admin & hopefully headaches for you the client

Fit out – Partitions

These costs are for premium quality toughened seamless glass partitions, bespoke joinery, Black Walnut doors, skirting boards, fitted kitchen – 32% of contract value

Mechanical & Electrical

These costs are for the electrical, data, alterations to lighting & fire strategy provision. So 2 x double power sockets and 2 x data outlets per workstation plus installation of AV Polycom system in the Boardroom 18% of contract value

Cat 5E data cabling installation & Installation of Air Conditioning Condenser

Seating, Storage, Desks and Furniture

This cost is to supply & install seating to 146 workstations, 2 number Meeting Rooms for 6 and a Boardroom accommodating 20. Representing 13% of the contract value

Office Seating & Kitchen Staff Breakout Seating

These costs include 4 large plan chests, 16 number chest height tambour storage units and 22 lineal Metres of full height bespoke storage fitted to 2 number wall areas – 10% of contract value

These costs are for the manufacture, supply & install of bespoke screens to all desks throughout the 10th floor – 13% of contract value

Bespoke desk-top screens


These costs are for supply & installation of screed and rubber stud flooring to Kitchen / Breakout and Print areas – 1% of contract value (Carpets were within Cat A costs – landlord)

Stud Rubber Flooring to Pepro Area & Kitchen

I hope the explanation above will help you the reader a better understanding of Landlord terms. It can be confusing looking at lease arrangements and the associated paperwork, what will and what won’t be included in Cat A. The pie chart and images are a snapshot of how costs were apportioned on a recently completed project.  All contracts differ, I hope this barometer of costs and the accompanying images will help demystify the fit out process and where the money is spent

We at Select Interiors Manchester have in-house design professionals and a designer with 33 year’s empirical experience of how the design translation process works at site level. There can be a disconnect between architects and design professionals and contractors in terms of build detailing. We at Select Interiors have both sides working collaboratively to realise your aspirations. Our experience as both designers and contractors can help save you costs and reduce the stress of the whole process.

Talk to the experts about how an engaging fit out can save you time, stress, and costs, call the Select Interiors design team on 0161 445 4040 or email sales@select-interiors.com 

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