Office fitout conversations are full of terms that sound simple but carry specific meanings in the commercial building context. Tenants hear them during lease negotiations, design meetings, contractor briefings, and building management correspondence, and the assumption is that everyone understands them the same way. They often do not. A word like “compliant” means one thing to a tenant and something quite different to a certifier. “Make good” sounds straightforward until the scope is defined. “Base building” seems clear until there is a dispute about where it ends and the fitout begins.
Misunderstanding these terms does not just cause confusion. It causes cost. A tenant who misunderstands what “provisional sum” means in a contract may budget incorrectly. A business owner who does not understand “practical completion” may assume the fitout is finished when legally it is not. A decision-maker who conflates “fire-rated” with “fireproof” may make partition choices based on a false sense of security.
This glossary defines the most commonly used office design and fitout terms in plain language, grouped by the stage of the fitout process where they are most likely to appear. Each definition explains what the term means in practice, not just in theory, and flags where the common misunderstandings sit.
Lease and Commercial Terms
Base building: The structure, services, and finishes provided by the landlord before any tenant fitout work begins. This typically includes the structural slab, columns, core walls, perimeter glazing, base building air-conditioning, fire services, and common-area finishes. The lease usually defines what is and is not base building, and the definition matters at lease end when the tenant must return the space to base building condition.
Make good: The tenant’s obligation to return the leased space to its pre-fitout or base building condition at the end of the lease. This usually means removing all tenant-installed partitions, ceilings, floor coverings, and services, and reinstating the base building elements to their original state. Make-good obligations are specified in the lease and can represent a significant cost that many tenants underestimate.
Defit: The physical process of removing an existing fitout from a tenanted space. A defit may be done as part of a make-good at lease end, or to clear the space for a new fitout. The scope can range from a partial strip of specific elements to a complete strip back to base building.
Incentive / contribution: A financial contribution from the landlord toward the tenant’s fitout cost, typically offered as part of the lease negotiation. Incentives are usually calculated per square metre and may be paid as a lump sum or offset against rent. The amount and conditions vary significantly between buildings and lease terms.
Lease term: The total period of the lease, including any option periods. The lease term directly affects fitout decisions because it determines how long the tenant will occupy the space and therefore how much value the fitout needs to deliver. Short leases demand different fitout strategies from long leases.
Design and Planning Terms
Space plan / layout: The floor plan drawing that shows how the office will be divided into rooms, workstations, circulation areas, and service zones. The space plan is the foundation document for the entire fitout and determines the partition layout, the services zones, and the furniture arrangement.
Brief: The document that describes what the tenant needs from the office. A good brief specifies headcount, room requirements, acoustic needs, technology requirements, storage needs, and finish expectations. Most briefs are too vague to produce accurate pricing or efficient design.
Fitout standard: The level of finish and specification applied to the fitout. Terms like “basic,” “mid-range,” and “premium” are used loosely in the industry, and the same term can mean very different things depending on who is using it. The fitout standard directly affects the cost per square metre.
Reflected ceiling plan (RCP): A drawing that shows the layout of the ceiling from above, as if the ceiling were reflected in a mirror on the floor. The RCP shows ceiling tile layout, light positions, diffuser locations, sprinkler heads, and partition head connections. It is one of the most important coordination drawings in a fitout.
Services zone: The space above the suspended ceiling and below the structural slab where air-conditioning ducts, electrical conduit, data cabling, fire services, and hydraulic pipes are routed. The depth and congestion of the services zone directly affects what can be built below it.
Partition and Wall Terms
Plasterboard partition: A wall system constructed from steel framing with plasterboard sheets fixed to each face. Plasterboard partitions are the most common wall type in Australian commercial offices and can deliver a wide range of acoustic, fire, and finish performance depending on the specification.
Glass partition: A wall system using glass panels held in aluminium or steel framing. Glass partitions allow light transfer and visual connection between spaces. Their acoustic performance depends on the glass type, the framing system, the door specification, and the ceiling junction detail.
Demountable partition: A partition system designed to be installed and removed without permanent damage to the base building. Demountable systems are typically glass or aluminium-framed and can be relocated or reconfigured. They generally cost more to install than plasterboard but less to remove at lease end.
Fire-rated partition: A partition that has been tested and certified to resist the passage of fire and smoke for a specified period, typically 60 or 120 minutes in commercial applications. Fire-rated plasterboard partitions must be built to the exact tested system specification, including the correct number of plasterboard layers, insulation type, and junction details.
Rw rating: The weighted sound reduction index of a wall system, measured in decibels. The Rw rating indicates how much airborne sound the wall reduces when tested under laboratory conditions. Higher numbers mean better acoustic performance. A typical single-stud plasterboard wall achieves Rw 38-42. A double-stud system achieves Rw 50-60.
Manifestation: Visual markings applied to glass partitions to make them visible and prevent collisions. The BCA requires manifestation at specific height bands on full-height glass that could be mistaken for an opening.
Stud: The vertical steel framing member inside a plasterboard partition. Studs are typically C-section steel at 600mm centres, supporting the plasterboard sheets on each face. Understanding how plasterboard walls are built helps tenants evaluate partition specifications.
Head track / base track: The horizontal steel framing members at the top and bottom of a plasterboard partition. The base track is fixed to the slab and the head track is fixed to or sealed against the ceiling structure. The quality of the seal at these junctions directly affects acoustic and fire performance.
Double glazing (internal): A glass partition system with two glass panels separated by an air gap, delivering significantly higher acoustic performance than single glazing. Double-glazed internal partitions are used where speech privacy is important but visual transparency is desired.
Construction and Delivery Terms
Construction sequence: The order in which the fitout is built. The correct sequence runs from strip-out through services rough-in, ceiling installation, partition construction, second-fix services, floor finishes, and furniture installation. Getting the sequence wrong causes rework, delays, and cost overruns.
Rough-in: The first phase of services installation, where ductwork, electrical conduit, data cabling, fire services, and hydraulic pipes are run through the ceiling void and wall cavities before the walls and ceilings are closed. Rough-in must be complete before partition sheeting begins because the services are concealed inside the wall or above the ceiling.
Second fix: The final phase of services installation, where surface-mounted devices including power points, light fittings, switches, data outlets, and air-conditioning grilles are fitted to the finished surfaces. Second fix happens after partitions are complete and painted.
Practical completion: The point at which the fitout is substantially complete and ready for occupation, with only minor defects remaining. Practical completion triggers the defects liability period and is the contractual milestone for handover. It does not mean the fitout is perfect; it means it is usable and the remaining items are minor.
Defects liability period (DLP): A period after practical completion, typically 12 months, during which the contractor is responsible for rectifying any defects that emerge in the fitout. Defects identified during the DLP must be rectified at the contractor’s cost.
Variation: A change to the agreed scope of work after the contract is signed. Variations can be initiated by the tenant (requesting changes), the contractor (identifying unforeseen conditions), or the certifier (requiring compliance changes). Variations add cost and time and are the primary driver of budget overruns on fitout projects.
Provisional sum: An estimated allowance included in a contract for work that cannot be precisely defined at the time of pricing. Common examples include base building remediation, landlord-required consultant fees, and services modifications that depend on site conditions. Provisional sums are adjusted up or down based on the actual cost of the work.
Lead time: The period between ordering a material or product and its delivery to site. Glass partition lead times are among the longest in a typical fitout and must be managed carefully to avoid programme delays.
Programme / Gantt chart: The construction schedule showing all activities, their duration, and their dependencies. The programme is the primary tool for managing the fitout timeline and identifying which activities are on the critical path.
Critical path: The sequence of activities in the programme that determines the minimum project duration. Any delay to a critical-path activity delays the entire project. Approvals, design decisions, and long-lead procurement are the most common critical-path items on fitout projects.
Compliance and Certification Terms
BCA / NCC: The Building Code of Australia, now part of the National Construction Code. The BCA sets the minimum standards for building work in Australia, including fire safety, structural adequacy, accessibility, energy efficiency, and health and amenity. All office fitout work must comply with the BCA.
Occupation Certificate (OC): A certificate issued by a building certifier confirming that the fitout complies with the BCA and is safe for occupation. An OC is legally required before a fitout can be occupied. Partition issues are a common cause of OC delays.
Construction Certificate (CC): A certificate issued before construction begins, confirming that the proposed design complies with the BCA. A CC is required for most commercial fitout work and must be obtained before construction can legally start.
Certifier / PCA: The Principal Certifying Authority responsible for issuing the Construction Certificate and the Occupation Certificate. The certifier inspects the fitout during and after construction to verify compliance with the approved plans and the BCA.
Fire compartment: A defined area of a building that is enclosed by fire-rated construction to contain fire and smoke for a specified period. Fitout partitions that form fire compartment boundaries must be fire-rated and must extend from slab to slab through the ceiling.
Essential services: Building services that are required by regulation to be maintained in operational condition at all times. Essential services include fire sprinklers, smoke detectors, emergency lighting, exit signs, fire doors, and mechanical smoke exhaust systems. Fitout changes can trigger new essential services obligations.
Section 133A: A provision in the NSW Conveyancing Act that limits a landlord’s ability to claim make-good costs to the actual diminution in value of the premises. Understanding Section 133A is important for tenants negotiating make-good obligations under NSW commercial leases.
Landlord consent / fitout approval: Written permission from the landlord or building manager to proceed with proposed fitout works. Most commercial leases require consent before any physical work begins, and the approval process can take two to eight weeks depending on the building and the scope of work.
Mechanical and Services Terms
HVAC: Heating, ventilation, and air conditioning. The mechanical system that maintains thermal comfort and air quality in the office. HVAC design must be coordinated with the partition layout because enclosed rooms change the air distribution pattern.
Supply air: Conditioned air delivered into the office through ceiling-mounted diffusers. Supply air provides the cooling, heating, and fresh air that maintains comfortable conditions.
Return air: Air drawn from the office back to the air-handling unit for reconditioning. Return air paths are as important as supply air, and rooms without adequate return air will not maintain comfortable temperatures.
BMS: Building Management System. The computer-controlled system that monitors and adjusts the building’s mechanical, electrical, and fire services. Tenant fitout modifications often require BMS programming changes coordinated through the landlord.
Transfer grille: A grille installed in or above a partition to allow air to pass between spaces. Transfer grilles provide return air paths for enclosed rooms but also allow sound to pass through, so acoustic transfer grilles with internal baffles are used where sound control is important.
Ceiling and Acoustic Terms
Suspended ceiling: A ceiling system hung below the structural slab using a metal grid that supports ceiling tiles. Suspended ceilings conceal services, provide acoustic absorption, and create a finished ceiling plane. The grid establishes the datum level for partition framing.
Ceiling void / plenum: The space between the suspended ceiling and the structural slab above. This space houses ductwork, electrical and data cabling, fire services, and other building systems. The depth and accessibility of the ceiling void directly affects what services can be accommodated and how partitions connect to the structure above.
NRC (Noise Reduction Coefficient): A measure of how much sound a surface absorbs, rated from 0 (fully reflective) to 1 (fully absorptive). Ceiling tiles with higher NRC values absorb more sound and reduce reverberation in open-plan areas.
Flanking path: A sound transmission route that bypasses the partition, typically through the ceiling void, under the floor, or through shared services. Flanking paths through the ceiling void are the most common cause of acoustic underperformance in glass offices.
Make Good and End-of-Lease Terms
Strip-out: The removal of a tenant’s fitout elements from the leased space. A strip-out may involve removing partitions, ceilings, floor coverings, joinery, and tenant-installed services. Strip-out is not the same as make good; make good includes reinstatement to base building condition after the strip-out.
Reinstatement: The process of returning base building elements to their original condition after the tenant’s fitout has been removed. This includes replacing ceiling tiles, patching the slab, reinstating fire-rated construction, and removing all evidence of the tenant’s occupation.
Condition report: A documented record of the space’s condition at a specific point in time, typically at lease commencement and lease end. Condition reports are essential for establishing the make-good benchmark and resolving disputes about what the tenant is responsible for reinstating.
Dilapidation: Damage or deterioration of the premises beyond fair wear and tear. Dilapidation can become a point of dispute at lease end if the tenant and landlord disagree about whether specific conditions are the result of the tenant’s fitout, fair wear and tear, or pre-existing building issues.
Flooring and Finish Terms
Carpet tile: Modular carpet squares, typically 500mm x 500mm, that are the standard floor covering in commercial offices. Carpet tiles can be individually replaced if damaged, are available in a wide range of colours and patterns, and provide acoustic absorption that reduces open-plan noise. Carpet tile selection affects both the acoustic environment and the visual identity of the space.
Vinyl plank / LVT: Luxury vinyl tile, a resilient floor covering that mimics timber or stone. LVT is common in kitchens, breakout areas, and reception zones where a premium appearance is desired without the cost or maintenance of natural materials. It is harder than carpet and provides less acoustic absorption, which may affect noise levels in open-plan areas where it is used extensively.
Level 5 finish: The highest standard of plasterboard surface preparation, involving a skim coat of compound over the entire wall surface before painting. Level 5 eliminates the visible difference between jointed and unjointed areas under raking light, and is required where the wall surface will be viewed under harsh lighting or where it adjoins glass partitions that amplify surface imperfections.
Bulkhead: A dropped ceiling section, typically constructed from plasterboard, that conceals services or creates a visual feature. Bulkheads are commonly used above reception desks, along corridor ceilings, and at the junction between glass partitions and the ceiling to provide a continuous seal for acoustic and fire performance.
Joinery: Custom-built cabinetry and millwork including reception desks, kitchens, storage units, and built-in furniture. Office joinery is fabricated off-site and installed during the final stages of the fitout programme.
If you are navigating fitout terminology and want clarity on what each term means for your specific project, we can help. We explain every decision in practical terms and manage the full fitout process from design through to handover.