How to Estimate a Commercial Fit-Out

The architectural fit-out is usually the first thing estimators measure, because it defines the floor plan and drives quantities for every trade that follows. Start from the approved fit-out drawings, not the leasing plan — a leasing plan shows intent, not buildable detail.

Each element carries its own rate build-up. Partitions are priced per linear or square metre depending on height and rating (acoustic, fire-rated, glazed); ceilings per square metre by system (grid, plasterboard, bulkhead); flooring per square metre by finish (carpet tile, vinyl, polished concrete); joinery as a schedule of items rather than a single rate (reception desks, kitchenettes, storage); and doors and glazing per opening, priced individually because hardware, framing and glazing type vary door to door.

• Partitions — stud type, height to slab or to ceiling, acoustic/fire rating
• Ceilings — grid vs plasterboard, bulkheads, acoustic treatment
• Flooring — finish type, subfloor preparation, skirting
• Joinery — priced as a schedule of items, not a blanket rate
• Doors and glazing — priced per opening, including hardware and framing

Mechanical, electrical, hydraulic, fire and data/comms services are usually the largest cost category in a commercial fit-out, often outweighing the architectural works, because every new partition, ceiling zone and workstation needs power, data, conditioned air and often fire coverage extended or reconfigured to reach it.

Mechanical (HVAC) pricing depends on whether the base building air handling has spare capacity for the new layout or needs supplementary units. Electrical covers power, lighting, switchboards and containment. Hydraulic covers any new wet areas — kitchenettes, amenities, tea points. Fire covers detection, sprinkler relocation and compliance with the base building fire engineering report. Data/comms covers cabling, comms rooms and connection to the building riser.

The table below is an illustrative cost-by-element breakdown for a typical office fit-out — a worked example showing how the categories relate to each other, not a quote. Real rates depend on tenancy condition, location, finish level and current market pricing, which is why every rate in a rates library needs to stay fully editable rather than fixed to a benchmark.

Base-build vs tenant works is the line between what the landlord already provides in the shell space and what the tenant must supply and pay for — and getting it wrong is one of the most common causes of an under-priced fit-out tender.

Before measuring a single item, confirm the base-build specification against the actual site condition rather than the drawings alone: does the floor have raised access already, is the mechanical system pre-conditioned to the tenancy, are sprinkler heads already dropped to the ceiling zone, is there a fire-rated corridor already built. Anything the base building does not provide becomes tenant scope, and anything ambiguous should be flagged as a qualification in the tender rather than assumed either way.

• Compare the landlord’s base-build specification against a physical site inspection, not just the drawings
• List every ambiguous item as a qualification or exclusion in the tender
• Where the base building falls short of what the design needs, price the shortfall as tenant works

Make-good obligations require the tenant to return the space to its original, or an agreed, condition at lease end, and a properly scoped fit-out estimate accounts for this cost from day one — either as a provisional sum or a separate make-good allowance in the tender.

Lease documents vary. Some require a full strip-out to base building condition, others accept a de-fit to a defined standard, and some allow an incoming tenant to take over the existing fit-out. Read the actual lease clause rather than assuming a standard make-good, and price the allowance accordingly rather than leaving it as an unpriced risk.

After-hours and restricted-access loadings apply when a building only allows fit-out works outside normal business hours, through a single freight lift, or with security escorts and noise restrictions — all of which slow production rates and increase labour cost compared with an unrestricted site.

Confirm the building’s access rules with the landlord or facilities manager before pricing, not after. A tenancy on a mid-level floor of an occupied CBD tower with one shared freight lift and a 6pm-to-6am works window carries a real productivity penalty that a ground-floor retail shell does not, and that loading needs to be built into labour rates or a specific site-conditions allowance rather than absorbed as margin risk.

• Lift access — shared vs dedicated, size and weight limits, booking windows
• Working hours — after-hours-only vs standard hours with noise limits
• Security and induction requirements that add non-productive time

Preliminaries and provisional sums cover the project-level costs and genuine unknowns that sit outside the measured trade quantities — site management, temporary protection, waste removal, and items that cannot be finalised until the works start.

Preliminaries are the fixed and time-related costs of running the job — supervision, site facilities, protection of common areas and existing base-build finishes, waste removal and insurances. Provisional sums are a defined allowance for items known to exist but that cannot be fully quantified at tender stage — for example, an allowance to make good unforeseen slab penetrations, or a prime cost item for a client-selected light fitting. Both need to be clearly listed, not buried inside trade rates, so the client can see exactly what they cover.