Case Study: Multi-Unit Apartment Development in Sydney — Design to Approval Timeline

Author: Franz Phan, Registered Design Practitioner (Class 2 buildings), Senior Planning Consultant — 15+ years experience in NSW residential development
Published: 28 August 2026
Reading time: ~10 minutes

Why a Class 2 Apartment Case Study Matters in 2026

NSW is racing to deliver 377,000 new homes by July 2029 under the National Housing Accord, and apartment development sits at the centre of that ambition. Yet the path from acquiring a site to pouring the first slab for a Class 2 apartment building is anything but straightforward. It involves pre-DA feasibility, Development Application lodgement, council assessment, Construction Certificate issuance, DBP Act regulated design declarations, BASIX certification, and principal certifier engagement — each stage carrying its own cost, timeline risk, and regulatory obligation.

This article walks through a real Class 2 apartment development project in Sydney from initial site assessment to construction certificate, drawing on giantA's project experience across Greater Sydney. The timelines, costs, and regulatory steps cited reflect actual projects delivered between 2024 and 2026, with suburb-level detail to illustrate how council-specific factors shape the approval journey. Where regulatory requirements are referenced, they are sourced from the NSW Planning Portal, the Environmental Planning and Assessment Act 1979, and the Design and Building Practitioners Act 2020 (NSW).

What Is a Class 2 Building and Why Does the Approval Pathway Differ?

A Class 2 building under the National Construction Code (NCC) Volume One is a multi-unit residential building containing two or more sole-occupancy units 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 townhouse, a Class 2 building cannot be approved via Complying Development Certificate (CDC) in most zones — it requires a Development Application (DA) through the local council, followed by a Construction Certificate (CC) before building work commences.

The regulatory distinction matters because the Design and Building Practitioners Act 2020 imposes mandatory compliance declaration requirements on all Class 2 projects. Every regulated design — architectural, structural, fire safety, hydraulic, mechanical — must be prepared by a registered design practitioner and declared before construction begins. This adds a layer of professional coordination and documentation that does not apply to Class 1 dwellings.

Project Profile: 8-Unit Apartment Building in Merrylands

The primary case study in this article is an 8-unit residential flat building in Merrylands, within the City of Parramatta local government area. The site was 1,180 m², zoned R4 Medium Density Residential, with a 25-metre frontage and a slight cross-fall of approximately 1.2 metres. The development comprised three storeys above a semi-basement carpark with 12 spaces, including one accessible space. Unit mix was two one-bedroom apartments (55 m² each), four two-bedroom apartments (78–85 m²), and two three-bedroom apartments (105 m²), targeting the entry-level investor market.

The project was acquired by the developer in February 2024, with giantA engaged for pre-DA feasibility in March 2024. The DA was lodged in July 2024, determined in November 2024, the Construction Certificate issued in February 2025, and construction commenced in March 2025. Practical completion was achieved in December 2025 — a total project timeline of approximately 22 months from site acquisition to handover. The table below breaks down each phase with its duration and key deliverables.

Phase 1: Site Feasibility and Pre-DA Planning (6 Weeks)

Feasibility is where every Class 2 project should begin — yet many developers skip this step and pay for it later. For the Merrylands site, giantA conducted an 8-source feasibility assessment covering zoning verification, site constraints (flooding, bushfire, acid sulphate soils), height and floor space ratio controls under the Parramatta Local Environmental Plan 2023, minimum lot size compliance, setback requirements, and parking provisions under the Parramatta Development Control Plan.

The critical finding from feasibility was that the site's 1,180 m² area exceeded the minimum 700 m² lot size for multi-dwelling housing in the R4 zone, but the 25-metre frontage created a constraint for basement carpark access. We recommended a semi-basement configuration with a ramp entry from the street, avoiding the need for mechanical ventilation of the carpark — a decision that saved approximately $80,000 in mechanical services costs and simplified the fire safety schedule. This is the kind of value that early professional involvement delivers: a design decision at feasibility stage that ripples through the entire project budget.

We also conducted a preliminary BASIX assessment at feasibility stage. BASIX (Building Sustainability Index) applies to all new Class 2 buildings in NSW and requires compliance across three categories: water, energy, and thermal comfort. The NSW Planning Portal BASIX tool was used to model the indicative score, confirming that a 5,000-litre rainwater tank, solar hot water system, and 7-star NatHERS thermal performance rating would be sufficient to meet the threshold without requiring expensive photovoltaic arrays or heat recovery ventilation.

Phase 2: DA Documentation and Pre-DA Meeting (12 Weeks)

The pre-DA design phase is where the SEPP 65 Design Quality of Residential Apartment Development and the NSW Apartment Design Guide come into play. These controls govern every aspect of apartment design in NSW — building separation, deep soil zones, solar access, cross-ventilation, ceiling heights, private open space, and storage provisions. Non-compliance with any of these can trigger a refusal or lengthy RFI (Request for Information) cycle.

For the Merrylands project, we arranged a pre-DA meeting with City of Parramatta Council in May 2024. The meeting identified three issues early: (1) the proposed building separation of 9 metres on the northern boundary was 3 metres short of the SEPP 65 requirement for a 3-storey building, requiring a design revision to setback the upper level; (2) the deep soil zone requirement of 12% of the site area was achievable but required reconfiguration of the basement footprint; and (3) solar access to the ground-floor units needed to be demonstrated for at least 2 hours on 21 June. Addressing these issues before lodging the DA saved approximately 4–6 weeks of assessment time that would otherwise have been lost to an RFI round.

The DA documentation set included architectural drawings (site plan, floor plans, elevations, sections), a BASIX certificate, a stormwater management plan, a waste management plan, an arborist report (two trees on the neighbouring property required consideration), a Landscape Concept Plan, and a Statement of Environmental Effects. All drawings were prepared by giantA as the registered design practitioner, with structural engineering input from a consulting engineer registered under the DBP Act for the building class.

Phase 3: DA Assessment and Determination (18 Weeks)

The DA was lodged on the NSW Planning Portal on 12 July 2024 and accepted by City of Parramatta Council after 5 business days. The statutory deemed refusal period for a standard local DA is 40 calendar days under the Environmental Planning and Assessment Regulation 2021, but this is a right of appeal — not a guarantee of determination. Actual assessment times across NSW vary dramatically, as shown in the table below.

Sources: NSW Planning Portal Council League Table, planning.nsw.gov.au; data extracted 31 May 2026.

The Merrylands DA received one RFI in September 2024, requesting additional solar access diagrams and clarification on the fire safety provisions for the basement carpark. We responded within 7 days, and the DA was determined on 15 November 2024 — a total of 126 days from lodgement, slightly above the Parramatta average but within the 105-day target for 2025–26. The consent included 12 conditions, including the standard requirement for a Construction Certificate before building work commences, BASIX certification at CC stage, and a pre-construction fire safety briefing.

This is where council selection of a development site becomes strategically important. A site in Hunters Hill would have faced an average determination time of 130+ days, while the same project in Lismore could have been determined in under 30 days. For developers evaluating multiple sites, understanding the council league table is as important as understanding zoning controls. The NSW Government's Faster Assessments Program has driven average DA times down from 115 days to 84 days nationally — a 31-day improvement since July 2024 — but the gap between best and worst performing councils remains over 100 days.

Phase 4: Construction Certificate and DBP Act Compliance (10 Weeks)

Once the DA is determined, the next phase is the Construction Certificate (CC). The CC is a separate approval that certifies the detailed construction plans are consistent with the DA consent and comply with the Building Code of Australia (BCA/NCC). For a Class 2 building, the CC phase also triggers the full weight of the Design and Building Practitioners Act 2020.

Under the DBP Act, every regulated design for a Class 2 building must be prepared by a registered design practitioner and declared via a Design Compliance Declaration before construction starts. The regulated designs include architectural drawings, structural engineering, fire safety systems, hydraulic services, mechanical ventilation, and any other designs declared by the Secretary. A Principal Design Practitioner must be appointed to coordinate the design declarations and issue a consolidated Design Declaration.

For the Merrylands project, the CC documentation phase involved:

1. Detailed construction drawings — expanded from DA-stage drawings to include full specifications, sections, and construction details. This was the largest documentation effort, requiring approximately 6 weeks of senior drafting time.

2. Structural engineering certification — a consulting engineer prepared the structural design for the three-storey concrete frame, including slab designs, footing systems (auger piles due to the reactive clay soil), and lateral load calculations. The engineer was registered under the DBP Act for the structural engineering class and issued a Design Compliance Declaration.

3. Fire safety schedule and design — a fire safety engineer prepared the fire safety schedule, including smoke alarms, smoke hazard management, fire-rated construction between units and the carpark, and exit provisions. This was critical for the acoustic separation between units, which required an STC 50 rating under the BCA Part F5.

4. BASIX certificate update — the BASIX certificate was updated from the DA-stage preliminary version to a final version, incorporating the confirmed materials, glazing specifications, and thermal performance modelling. The 7-star NatHERS rating was achieved with R4.0 ceiling insulation, R2.5 wall insulation, double-glazed windows, and careful orientation of living areas to the north.

The CC was issued by a private certifier on 18 February 2025 — 10 weeks after DA determination. The private certifier was engaged as the Principal Certifier for the project, responsible for critical stage inspections and the final Occupation Certificate.

Phase 5: Construction and Occupation Certificate (10 Months)

Construction commenced on 3 March 2025 and reached practical completion on 12 December 2025 — a 10-month build period. The construction cost was approximately $2.3 million, equating to roughly $3,200 per square metre of gross floor area (GFA). This sits within the mid-range for Sydney Class 2 construction, which typically runs from $2,800 to $4,500 per square metre depending on site complexity, finish level, and basement configuration.

The critical stage inspections conducted by the Principal Certifier included: (1) pier/shaft excavation (footings), (2) steel reinforcement (slabs and frames), (3) frame and trusses, (4) waterproofing, (5) wet area flashing, (6) stormwater drainage, and (7) final inspection. Each inspection required 24–48 hours' notice and typically took 1–2 hours on site.

The Occupation Certificate (OC) was issued on 19 December 2025, one week after practical completion. The OC is the final regulatory approval for a Class 2 building — it certifies that the building is suitable for occupation and that all DA conditions have been satisfied. For this project, the OC conditions included the final BASIX certification, the fire safety certificate, and the as-built drawings lodged with the council.

Second Case Study: 6-Unit Walk-Up in Liverpool

A second project illustrates how a different council and site type can shift the timeline. In Liverpool, giantA designed a 6-unit walk-up apartment building (no lift, no basement — ground-level parking) on a 720 m² site zoned R4. The smaller scale and simpler construction meant the DA was determined in 68 days by Liverpool City Council — faster than the Parramatta project. However, the CC phase took 14 weeks instead of 10, because a geotechnical investigation revealed reactive clay at 1.8 metres depth, requiring strip footing redesign and an additional engineer's site visit. The total project timeline was 19 months, 3 months shorter than Merrylands, with construction costs of approximately $1.6 million ($2,900/m²).

The Liverpool project highlights two lessons: first, simpler typologies (walk-up vs. basement) reduce both construction cost and timeline; second, geotechnical risk can materialise at any stage, and a thorough soil test at feasibility stage is the best insurance against late-stage redesign.

Common Pitfalls That Extend Class 2 Approval Timelines

Across the two projects and additional giantA Class 2 developments, several recurring pitfalls extend the approval timeline or inflate costs. These are the issues that developers and builders should plan for from day one:

1. Incomplete DA documentation — the most common cause of RFI delays. Missing arborist reports, incomplete stormwater plans, or absent BASIX certificates trigger an RFI cycle that adds 2–4 weeks to the assessment. A complete DA documentation set should be checked against the council's DA checklist before lodgement.

2. SEPP 65 non-compliance discovered late — building separation, solar access, and deep soil requirements are frequently missed at concept design stage. A pre-DA meeting with council is the most cost-effective way to identify these issues early, costing approximately $500–$1,000 in council fees but saving weeks of redesign.

3. DBP Act declaration gaps — all regulated designs must be declared before construction starts. If a design practitioner is not registered for the relevant class, or if a design is modified during construction without a variation declaration, the project risks a stop-work order. Always verify practitioner registration at engagement stage.

4. BASIX underperformance — the updated BASIX standards (effective from 1 October 2023) require 7-star NatHERS thermal performance, a 7–11% reduction in greenhouse gas emissions, and compliance with the new materials index. Designs that were modelled under the old 5.5–6 star requirements will fail the current BASIX tool.

5. Inadequate contingency — the Merrylands project ran with a 4.3% contingency, which is below the recommended 5–7% for Class 2 construction. A basement water ingress incident in October 2025 required $22,000 in remedial work, which was absorbed by the builder's margin rather than the contingency. For Class 2 projects, a minimum 7% contingency is recommended.

How NSW Planning Reforms Are Changing the Timeline

The NSW Government's Faster Assessments Program has driven significant improvement in DA determination times. From 1 July 2026, councils are working towards an average determination period of 95 days, reducing to 85 days from July 2027. The Statement of Expectations Order 2026 came into effect on 1 July 2026, with $200 million in financial incentives available to councils through the Faster Assessments Incentive Program.

For Class 2 developers, this means the DA assessment phase is becoming more predictable — but only for complete, well-documented applications. Councils still have the right to issue RFIs, and the assessment clock pauses while the applicant responds. The quality of the DA documentation set remains the single biggest controllable factor in the approval timeline.

The Low-Rise Housing Reforms 2026 introduce targeted assessment pathways that could halve DA times for certain low-rise residential developments, though Class 2 apartment buildings above two storeys are not yet included in the fast-track provisions. Developers should monitor planning.nsw.gov.au for updates to the eligible building classes.

FAQ: Class 2 Apartment Development in NSW

How long does a Class 2 apartment DA take in NSW?

A Class 2 apartment DA in NSW takes an average of 84 days from lodgement to determination as of May 2026, down from 115 days in July 2024. The statutory deemed refusal period is 40 days for a standard local DA, but actual assessment times range from 22 days (Lismore) to over 125 days (Hunters Hill) depending on the council. Well-documented DAs with pre-DA meetings tend to be determined faster.

Can a Class 2 building be approved via CDC instead of DA?

Most Class 2 apartment buildings require a Development Application (DA) through local council, not a Complying Development Certificate (CDC). The NSW Planning Portal does offer a Class 2 CDC pathway for certain low-rise apartment developments that meet specific criteria, but this is limited to buildings up to two storeys in nominated zones. Most three-storey and above Class 2 buildings must follow the DA pathway. Check eligibility via the Planning Portal's online CDC tool.

What is the DBP Act and how does it affect Class 2 development?

The Design and Building Practitioners Act 2020 (NSW) requires all design practitioners working on Class 2 buildings to be registered and to issue Design Compliance Declarations for regulated designs before construction starts. This includes architectural, structural, fire safety, hydraulic, and mechanical designs. A Principal Design Practitioner must coordinate the declarations. The Act applies to all Class 2 buildings in NSW regardless of approval pathway.

How much does it cost to design and get approval for a Class 2 building?

Professional design and approval costs for a Class 2 apartment building in Sydney typically range from $98,000 to $147,000, covering feasibility, DA documentation, CC documentation, DBP Act declarations, BASIX certification, and certifier fees. This excludes construction costs, which range from $2,800 to $4,500 per square metre. For an 8-unit building of approximately 720 m² GFA, total design and approval costs are approximately $120,000.

What is a Construction Certificate and when do I need it?

A Construction Certificate (CC) is the second-stage approval required after a DA is determined, certifying that detailed construction plans comply with the Building Code of Australia and are consistent with the DA consent. You cannot lawfully commence construction without a CC. The CC is typically issued by a private certifier within 8–12 weeks of DA determination, and requires full DBP Act regulated designs, structural certification, fire safety schedule, and an updated BASIX certificate.

Does BASIX apply to Class 2 apartment buildings?

Yes, BASIX applies to all new Class 2 buildings in NSW. The BASIX certificate must be obtained before DA lodgement and updated at CC stage. Current requirements include 7-star NatHERS thermal performance, water efficiency targets (rainwater tanks or alternative water sources), and energy efficiency measures (solar hot water, efficient lighting, and in some cases solar PV). The May 2026 BASIX tool upgrades introduced a Passive House Standard method as an alternative compliance pathway.

What is the difference between a Class 2 and Class 1 building?

A Class 2 building is a multi-unit residential building where two or more sole-occupancy units are stacked vertically, such as an apartment block. A Class 1 building is a detached house, duplex, or townhouse where each dwelling is a standalone structure. Class 2 buildings fall under NCC Volume One with stricter requirements for fire separation, accessibility, acoustic performance, and structural resilience. Class 1 buildings fall under NCC Volume Two.

How can I reduce the approval timeline for my Class 2 project?

The most effective ways to reduce a Class 2 DA timeline are: (1) hold a pre-DA meeting with council to identify compliance issues early; (2) submit a complete DA documentation set checked against the council's checklist; (3) engage registered design practitioners at concept stage to ensure DBP Act compliance; (4) conduct a thorough site feasibility assessment including soil testing; and (5) respond to RFIs within 7 days to minimise clock stoppage. Pre-DA meetings typically cost $500–$1,000 but save 4–6 weeks.

About the Author: Franz Phan is a Registered Design Practitioner under the Design and Building Practitioners Act 2020 (NSW), authorised to prepare regulated designs for Class 2 buildings. With 15+ years of experience in NSW residential development, Franz has delivered over 200 multi-unit and residential projects across Greater Sydney. Contact giantA for a free Class 2 feasibility assessment.

Sources:

1. NSW Planning Portal — Council League Table: planning.nsw.gov.au
2. NSW Government — Statement of Expectations Order 2026: planning.nsw.gov.au
3. NSW Planning Portal — BASIX: planningportal.nsw.gov.au/basix
4. Design and Building Practitioners Act 2020 (NSW) — legislation.nsw.gov.au
5. Environmental Planning and Assessment Act 1979 (NSW) — legislation.nsw.gov.au
6. National Construction Code 2022 — Australian Building Codes Board: ncc.abcb.gov.au