A Cat A fit-out prepares a raw shell space with basic services and finishes, while a Cat B fit-out transforms that space into a fully functional, branded workplace. If you’re leasing commercial office space in Ireland, understanding the difference between these two fit-out categories will help you budget accurately, negotiate your lease, and avoid paying for work that’s already been done.

This guide explains what each category covers, what each costs, and how to determine which type of fit-out your project needs.

What is a Cat A fit-out?

A Cat A fit-out — also called a Category A or shell fit-out — is the base-level preparation of a commercial space. It’s typically carried out by the landlord or developer before a tenant takes possession. The goal is to bring the space to a “ready to occupy” standard, with all essential building services in place but no tenant-specific customisation.

A Cat A fit-out in Ireland typically includes:

• Raised access flooring — providing cable management and service distribution beneath the floor
• Suspended ceiling grid — with basic ceiling tiles and recessed lighting
• Mechanical services — HVAC (heating, ventilation, and air conditioning) to a basic, zoned specification
• Electrical services — main distribution boards, basic lighting, and emergency lighting
• Fire detection and protection — smoke detectors, sprinklers, fire alarm system
• Lift lobbies and common areas — finished to the building’s standard
• Toilet facilities — core washrooms serving the floor
• Basic wall finishes — typically painted plaster or plasterboard to perimeter walls

Cat A fit-out costs in Ireland typically range from €400 to €700 per square metre, depending on the building’s age and existing condition. In newer developments, the landlord often delivers a Cat A spec as part of the lease agreement.

What is a Cat B fit-out?

A Cat B fit-out — or Category B — is the tenant’s fit-out. It takes the Cat A shell and transforms it into a finished, operational workspace tailored to the specific needs of the occupier. This is where the office becomes yours — your layout, your brand, your furniture, your technology.

A Cat B fit-out in Ireland typically includes:

• Space planning and layout — workstation positioning, circulation routes, zoning
• Partitioning — plasterboard, glazed, or acoustic partitions to create offices, meeting rooms, and breakout areas
• Flooring — carpet tiles, vinyl, timber, or polished concrete over the raised floor
• Enhanced lighting — task lighting, feature lighting, and lighting controls beyond the basic Cat A provision
• Furniture — desks, chairs, storage, meeting room tables, soft furnishings
• Data and communications — structured cabling, Wi-Fi infrastructure, server room or comms room
• Kitchen and breakout — tea points, full kitchens, breakout seating, vending
• Corporate branding — signage, feature walls, colour schemes, environmental graphics
• AV and technology — screens, video conferencing, room booking systems
• Security and access control — door access systems, CCTV, intruder detection
• Reception area — bespoke reception desk, waiting area, visitor management

Cat B fit-out costs in Ireland range from €700 to €1,500 per square metre, depending on whether you’re targeting a basic, mid-range, or premium specification. See our detailed office fit-out cost guide for a full breakdown.

What’s the difference between Cat A and Cat B? A side-by-side comparison

Who pays for what in a commercial lease?

In most Irish commercial leases, the landlord covers Cat A costs and the tenant covers Cat B. However, this isn’t always straightforward:

• Landlord contribution. In competitive markets, landlords may offer a fit-out contribution (often called a “tenant improvement allowance”) towards Cat B costs. In Dublin’s current market, contributions of €100–€300 per square metre are not uncommon for desirable tenants signing longer leases.
• Rent-free periods. Instead of a direct contribution, landlords may offer a rent-free period (typically 3–12 months) to allow tenants to fit out without paying rent simultaneously.
• Pre-fitted spaces. Some landlords offer “plug and play” or pre-fitted spaces where both Cat A and basic Cat B work has been completed. These spaces come at a rent premium but reduce upfront capital expenditure for the tenant.

Understanding these negotiation levers is important when budgeting for your fit-out. At Chawner & Trench, we often advise clients on what to negotiate for before the lease is signed — it’s much harder to get concessions after you’ve committed.

Which type of fit-out do you need?

The answer depends on what state your space is in when you take possession:

You need a Cat A fit-out if:

• You’re taking a raw shell space with no services or finishes
• You’re a developer or landlord preparing a space for the market
• The existing Cat A is outdated and needs replacing (e.g., old ceiling grid, inadequate HVAC)

You need a Cat B fit-out if:

• You’re moving into a space that already has a Cat A specification
• You need to create a branded, functional workspace for your team
• You’re relocating, expanding, or modernising your office

You may need both if:

• You’re taking a completely raw shell space and need to go from bare concrete to a finished office
• The existing Cat A specification doesn’t meet current standards (common in buildings over 15 years old)

If you’re not sure what state your space is in, book a free on-site survey and we’ll assess it for you.

How long does each type of fit-out take?

Typical timelines for office fit-outs in Ireland:

Cat A and Cat B can sometimes overlap, with Cat B design work starting while Cat A construction is still underway. This can reduce the combined timeline by 4–6 weeks.

Frequently Asked Questions

Can you do a Cat B fit-out without Cat A?

No. Cat B work builds on top of Cat A infrastructure. You need raised floors, ceiling grids, and basic M&E services in place before you can begin partitioning, furnishing, and fitting out the space. If your space doesn’t have a Cat A specification, both categories of work need to be completed.

Does Cat A include toilets and kitchens?

Cat A typically includes core toilets (shared facilities on each floor, usually in the building’s common areas). It does not include tenant kitchens, tea points, or breakout areas — these are Cat B items.

What is a Cat A+ fit-out?

Cat A+ (or “white box plus”) is an increasingly common term for a fit-out that goes slightly beyond standard Cat A. It might include enhanced lighting, better quality flooring, or a basic open-plan layout. Landlords offer Cat A+ specifications to make spaces more attractive to prospective tenants and reduce the tenant’s Cat B costs.

Who manages a Cat B fit-out?

The tenant is responsible for their Cat B fit-out. Most businesses engage a specialist fit-out contractor like Chawner & Trench to manage the entire process — from initial design through construction to furniture installation and handover. This turnkey approach means you deal with one team rather than coordinating multiple contractors.

Simon Chawner is the co-founder and Project Manager at Chawner & Trench. An Associate member of the Society of Chartered Surveyors Ireland (SCSI), Simon holds qualifications in Facilities & Property Management and is a PMBOK-certified Project Manager. He has over 15 years of experience managing commercial office fit-outs across Ireland.