Author: Franz Phan, Registered Design Practitioner (Class 2 buildings), Senior Planning Consultant — 15+ years experience in NSW residential development
Published: 13 August 2026
Reading time: ~9 minutes
Why Class 2 Cost Transparency Matters in 2026
The cost of delivering a Class 2 apartment building in Sydney has shifted dramatically over the past three years. Construction costs now sit approximately 30.8% above pre-COVID levels, and the average build timeline has extended from 24.5 months to 29 months, amplifying financing and contingency pressures across every project phase. For developers and investors evaluating apartment feasibility in 2026, understanding the split between professional design fees and hard construction costs is not a luxury — it is the difference between a viable project and one that stalls at feasibility stage.
This article breaks down the real costs of designing and building a Class 2 apartment project in Sydney, drawing on current per-square-metre rates, DBP Act compliance overheads, council and statutory fees, and giantA's project experience across Greater Sydney from 2024 to 2026. Every figure cited is sourced from publicly available construction cost data or NSW government fee schedules, and where ranges are given, the assumptions behind them are explained.
What Is a Class 2 Building and Why Does It Cost More?
A Class 2 building under the National Construction Code (NCC) is a multi-unit residential building containing two or more sole-occupancy units (SOUs) where people live above and below each other. This classification covers apartment blocks, residential flat buildings, and units over shared carparks. Unlike a Class 1 dwelling (a detached house or townhouse), a Class 2 building falls under NCC Volume One, which imposes stricter requirements for fire separation, structural resilience, accessibility, acoustic performance, and services coordination.
These regulatory obligations translate directly into cost. Fire-rated construction, inter-tenancy acoustic separation, common area finishes, lift installations, basement parking ventilation, and Building Solution compliance all add layers of expenditure that simply do not exist in a detached house build. A Class 2 project also requires engagement of registered design practitioners under the Design and Building Practitioners Act 2020 (NSW), adding a compliance overhead that is both a cost and a risk-management safeguard.
Construction Cost Per Square Metre: Sydney 2026 Benchmarks
Construction cost per square metre is the foundational metric for Class 2 feasibility modelling. The following table draws on 2026 forecast data from Australian construction cost analysts, cross-referenced with the AIQS Building Cost Index and Sydney-specific rates from quantity surveying firms.
Table 1: Apartment Construction Cost Per m2 in Sydney (2026 Forecast)
| Building Type | Cost Range (AUD per m2 GFA) | Key Cost Drivers |
|---|---|---|
| Low-rise (2-4 storeys) | $2,450 - $3,400 | Basic finishes, simpler structural design, ground-level parking |
| Mid-rise (5-8 storeys) | $3,000 - $4,000 | Underground parking, lift systems, fire engineering |
| High-rise (9+ storeys) | $3,700 - $5,400 | Complex engineering, wind loading, enhanced fire systems |
| Premium / Luxury | $5,500 - $8,000+ | Imported materials, bespoke interiors, extensive amenities |
Sources: Homenly Australian Apartment Construction Cost Review 2025/2026; AIQS Building Cost Index (Sept 2023, adjusted for 2026 escalation); Section 94 High-Density Development Cost Estimation.
An important caveat: these rates apply to Gross Floor Area (GFA), which includes corridors, lobbies, service risers, and common areas. The saleable internal apartment area is typically only 70-85% of GFA on a mid-rise project. Developers who apply a GFA rate to their net saleable area will systematically understate the build cost — sometimes by the entire development margin.
Table 2: Additional Construction Cost Components (Sydney 2026)
| Cost Component | Rate / Range | Notes |
|---|---|---|
| Basement parking (per space) | $25,000 - $45,000 | Single-level: $25-32k; double-level: $35-45k |
| Excavation in rock (per m3) | $150 - $300 | Sydney sandstone common in inner suburbs |
| Mechanical ventilation (per m2) | $180 - $250 | Basement and common area requirements |
| Waterproofing (per m2) | $85 - $120 | Critical for below-grade and wet area compliance |
| EV charging infrastructure (per space) | $3,500 - $8,500 | NCC 2025 accessibility and sustainability requirements |
| Swimming pool (shared amenity) | $145,000 - $280,000 | Common in mid-to-high-rise developments |
| Concierge facilities | $285,000 - $450,000 | Premium developments only |
Source: Section 94 High-Density Development Cost Estimation (2025).
Design and Professional Fees: The Soft Cost Breakdown
Professional fees for a Class 2 apartment project typically represent 8-15% of total construction cost, depending on the scope of services, project complexity, and whether construction administration is included. The DBP Act has added a new layer of mandatory professional engagement that did not exist before 2021, and developers who fail to budget for it encounter cost overruns during the pre-construction phase.
Table 3: Professional Fee Breakdown for a Class 2 Apartment Project (Sydney 2026)
| Professional Service | Fee Basis | Typical Range | DBP Act Mandatory? |
|---|---|---|---|
| Architect / Building Designer | % of construction cost | 6-12% | Design work yes; registration required for regulated designs |
| Registered Design Practitioner (structural) | Fixed fee or % | 1.5-3% of structural cost | Yes - mandatory under DBP Act |
| Registered Design Practitioner (fire safety) | Fixed fee | $15,000 - $45,000 | Yes - mandatory for Class 2 |
| Registered Design Practitioner (waterproofing) | Fixed fee | $5,000 - $15,000 | Yes - mandatory for Class 2 |
| Principal Design Practitioner (PDP) coordination | Fixed fee | $8,000 - $20,000 | Yes - mandatory for multi-discipline projects |
| Building certifier / Principal Certifier | Fixed fee | $8,000 - $25,000 | Yes - required for CC and OC |
| BASIX assessor | Fixed fee | $1,500 - $4,000 | Yes - BASIX certificate required for DA |
| NatHERS assessor (7-star) | Fixed fee | $800 - $2,500 | Yes - thermal performance compliance |
| Geotechnical engineer | Fixed fee | $3,000 - $12,000 | Site-dependent |
| Hydraulic engineer | Fixed fee | $5,000 - $20,000 | Required for services coordination |
| Acoustic consultant | Fixed fee | $3,000 - $15,000 | Required for inter-tenancy separation compliance |
| Town planner (DA lodgement) | Fixed fee | $5,000 - $20,000 | Recommended for complex DAs |
Sources: Siana Architect Fee Report 2026; Monograph Fee Estimating Guidelines 2026; giantA project records 2024-2026; Bannermans Lawyers DBP Act Guide.
The DBP Act compliance overhead — practitioner registration, design compliance declarations, and variation documentation — adds approximately 3-5% to total professional fees compared to pre-2021 projects. This is not optional. A builder cannot lawfully carry out building work that requires a regulated design until a final design is received with a design compliance declaration from a registered design practitioner.
Statutory and Council Fees: The Fixed Cost Layer
Unlike professional fees, which can be negotiated, statutory fees are set by regulation and scale with your estimated development cost (EDC). The council DA fee is calculated on a tiered basis under the Environmental Planning and Assessment Regulation 2021, with the fee unit for 2025/26 set at $113.90.
For a Class 2 apartment project with an estimated development cost of $5 million, the council DA fee typically falls between $15,000 and $25,000, depending on the council. On top of this, a Building and Construction Industry long service levy of 0.25% applies to works valued at $25,000 or more — equating to $12,500 on a $5 million project. Section 7.12 (formerly Section 94) development contributions may also apply, calculated as a percentage of the development cost, typically 0.5% to 1% depending on the council's contributions plan.
The total statutory and council fee layer for a mid-rise Class 2 project in Sydney commonly ranges from $40,000 to $80,000, inclusive of the DA fee, long service levy, contributions, BASIX certificate lodgement, and occupation certificate fees. These costs are predictable and should be locked into the feasibility model early. For a complete guide to the Class 2 approval pathway, see our dedicated guide.
Real Project Examples from giantA's Portfolio
Project 1: 8-Unit Low-Rise in Merrylands (Cumberland Council)
A two-storey walk-up apartment building with eight units, completed in late 2025. Total GFA of 720 m2 on a 650 m2 site. Construction cost landed at approximately $2.85 million ($3,960/m2), reflecting the compact footprint and standard finishes. Professional fees totalled $340,000 (12% of construction cost), with the DBP Act compliance layer accounting for $45,000 of that figure. The DA was approved in 11 weeks, and the construction certificate issued 4 weeks later. Total project cost from land acquisition to occupation certificate: approximately $3.6 million.
Project 2: 24-Unit Mid-Rise in Parramatta (City of Parramatta Council)
A six-storey apartment building with basement parking, completed in early 2026. GFA of 2,800 m2 with 24 units averaging 95 m2 each. Construction cost reached $10.2 million ($3,643/m2), with premium common area finishes and a shared rooftop garden adding $280,000. Professional fees came in at $1.1 million (10.8% of construction cost), reflecting the need for fire engineering, acoustic consultancy, and full DBP Act compliance across five regulated design disciplines. The DA process took 16 weeks, with an additional 6 weeks for the construction certificate. The project achieved a 7-star NatHERS rating across all units.
Project 3: 6-Unit Townhouse-Style Class 2 in Bankstown (Canterbury-Bankstown Council)
A three-storey development with six units over shared ground-level parking. GFA of 540 m2. Construction cost of $1.68 million ($3,111/m2), with professional fees at $185,000 (11% of construction cost). This project demonstrated that Class 2 compliance costs are proportionally higher for smaller projects — the DBP Act overhead represented 4.2% of professional fees, compared to 3.1% on the larger Parramatta project. The DA was approved in 8 weeks under a complying pathway with council variations.
How Design Choices Impact Total Project Cost
The decisions made during the design phase have a disproportionate impact on total project cost. A simplified structural grid, standardised unit layouts, and rationalised service risers can reduce construction cost by 5-8% without compromising quality or compliance. Conversely, complex facade geometries, bespoke unit configurations, and non-standard material selections can push costs 15-25% above benchmark rates.
For Class 2 projects specifically, the fire safety strategy is the single most consequential design decision. A performance-based fire engineering solution (Alternative Solution under BCA Section C) can deliver significant savings over a deemed-to-satisfy approach, but it requires early engagement of a fire safety engineer and coordination with the registered design practitioner. On the Parramatta project, the performance-based approach saved approximately $180,000 in fire-rated construction costs, against a fire engineering fee of $28,000.
Acoustic separation between units is another area where design efficiency matters. The BCA requires a minimum Rw 50 rating for inter-tenancy walls and floors. Exceeding this to achieve Rw 55 or higher — which is increasingly expected by purchasers and strata insurers — adds $40-80 per square metre of separating element. Designing unit layouts to minimise shared walls and align wet areas back-to-back reduces the total area of acoustic separation required, lowering both material and labour costs. For more on this topic, see our guide to acoustic and separation requirements for multi-unit dwellings.
Budgeting for Contingency: What Developers Actually Spend
Industry guidance suggests a contingency of 10-15% for Class 2 projects in the current market. This is not arbitrary — it reflects the extended construction timeline (29 months on average), the risk of design variations during construction (which trigger new DBP Act compliance declarations), and the volatility of specialist trade availability.
In giantA's experience, projects that allocated 12% contingency generally came in on budget. Projects that allocated 8% or less experienced cost overruns of 4-7% above the original construction budget, primarily driven by design variations and extended construction periods. The contingency should be treated as a managed cost reserve, not a target for value engineering. For common pitfalls to avoid, see our article on common Class 2 building design mistakes.
Frequently Asked Questions
How much does it cost to build a Class 2 apartment building in Sydney in 2026?
Construction costs for a Class 2 apartment building in Sydney range from $2,450 per m2 for a low-rise building with standard finishes to $5,400+ per m2 for a high-rise project with complex engineering. A typical mid-rise development (5-8 storeys) costs $3,000-$4,000 per m2 of GFA. These rates exclude land, professional fees, and statutory charges, which add a further 15-25% to the total project cost.
What are the design fees for a Class 2 apartment project?
Professional design fees for a Class 2 apartment project typically range from 8% to 15% of the total construction cost, depending on the scope of services and project complexity. A mid-rise project with 24 units and a construction budget of $10 million would expect professional fees of $800,000 to $1.5 million, inclusive of architect, engineering, DBP Act compliance, and specialist consultants.
Does the DBP Act add cost to apartment development?
Yes. The Design and Building Practitioners Act 2020 adds approximately 3-5% to total professional fees through mandatory registered design practitioner engagement, design compliance declarations, and variation documentation. For a $10 million construction project, this represents an additional $30,000 to $50,000 in compliance-related professional fees. These costs are mandatory and cannot be avoided for Class 2 buildings.
What is the council DA fee for an apartment building in NSW?
The council DA fee for a Class 2 apartment building is calculated on a tiered scale based on the estimated development cost under the Environmental Planning and Assessment Regulation 2021. For a project with an estimated development cost of $5 million, the DA fee typically falls between $15,000 and $25,000. A long service levy of 0.25% also applies, adding $12,500 on a $5 million project.
How does building height affect apartment construction costs?
Building height significantly affects unit costs through structural complexity and service requirements. Low-rise buildings (2-4 storeys) cost $2,450-$3,400 per m2, mid-rise (5-8 storeys) range from $3,000-$4,000 per m2, and high-rise (9+ storeys) reach $3,700-$5,400 per m2. Additional costs for high-rise include crane hire ($8,000-$15,000 weekly), wind engineering, enhanced fire systems, and multiple lift banks.
Can I reduce the cost of DBP Act compliance?
You cannot eliminate DBP Act compliance costs for Class 2 buildings, but you can optimise them. Engaging a Principal Design Practitioner early to coordinate all regulated designs reduces variation risk during construction. Finalising designs before lodging the DA, rather than iterating during assessment, minimises the need for additional compliance declarations. On giantA projects, early PDP engagement reduced DBP-related cost overruns by 60% compared to projects where coordination was reactive.
What contingency should I budget for a Class 2 project?
A contingency of 10-15% of the construction budget is recommended for Class 2 projects in 2026, reflecting extended construction timelines (29 months on average), the risk of design variations, and specialist trade availability. Projects allocating 12% contingency generally deliver on budget in giantA's experience, while those allocating 8% or less typically experience overruns of 4-7%.
What is the difference between GFA and saleable area for cost estimation?
Gross Floor Area (GFA) includes all enclosed areas of the building — apartments, corridors, lobbies, service risers, and common areas. Saleable area is the internal apartment space only, typically 70-85% of GFA on a mid-rise project. Construction cost rates are quoted per m2 of GFA. Applying a GFA rate to saleable area understates the build cost by the efficiency gap, which can eliminate the entire development margin on a tightly modelled project.
Key Takeaways for Developers and Investors
The total cost of a Class 2 apartment project in Sydney encompasses three distinct layers: hard construction costs (60-70% of total), professional design and compliance fees (8-15%), and statutory and council charges (3-5%). The remaining 10-20% is contingency, financing, and land. Understanding these proportions — and modelling them against current per-square-metre rates — is the foundation of a robust feasibility assessment.
The DBP Act has permanently changed the cost structure of Class 2 development. Developers who treat compliance as an afterthought will encounter delays, cost overruns, and potential certifier refusal. Those who engage registered practitioners early, finalise designs before DA lodgement, and budget for compliance declarations as a line item — not a contingency draw — will deliver projects on time and on budget.
For specific cost modelling on your Class 2 project, including a tailored fee proposal and DBP Act compliance plan, contact giantA Pty Ltd. We are a registered design practitioner firm under the DBP Act, authorised to prepare regulated designs and design compliance declarations for Class 2 buildings across NSW.
Contact giantA Pty Ltd
Phone: 02 8005 6336
Email: he@gianta.com.au
Web: www.gianta.com.au
NSW Registered Design Practitioner — Class 2, 3 and 9c buildings
This article is based on publicly available construction cost data, NSW government fee schedules, and giantA project records from 2024-2026. All cost figures are indicative and should not be relied upon as a substitute for project-specific professional advice. Construction costs vary significantly by location, site conditions, specification level, and market conditions.