Case Study: Multi-Unit Apartment Development in Sydney — Design to Approval Timeline
Author: Franz Phan, Registered Design Practitioner (NSW Design and Building Practitioners Act 2021), 15+ years experience in multi-residential design
Published: August 16, 2026
Category: Case Studies
Tags: class-2-building, apartment-design, design-practitioner, nsw-building-compliance, multi-residential
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Introduction
When a developer purchases a site in Greater Sydney with apartment development potential, the path from concept sketch to construction certificate is rarely linear. Every Class 2 building — defined under the National Construction Code (NCC) Volume One as a building containing two or more sole-occupancy units — carries a unique set of regulatory, design, and coordination challenges that shape the project timeline in ways no spreadsheet can fully anticipate.
This article walks through the complete design-to-approval timeline of three real Class 2 apartment developments giantA has delivered across Sydney. Each project faced different planning constraints, different council expectations, and different compliance hurdles under the Design and Building Practitioners Act 2020. By examining what happened at each stage — and where time was saved or lost — developers, builders, and investors can calibrate their own project expectations for 2026 and beyond.
The NSW government has set a target of 377,000 new homes by July 2029 under the National Housing Accord, and the Housing Taskforce reported 94% on-time performance in 2024–25. But "on time" at a macro level does not mean individual projects sail through. The difference between a 14-week approval and a 9-month approval often comes down to who you engage, when you engage them, and how thoroughly the regulated design documentation is prepared before lodgement.
The Three Projects at a Glance
Before diving into the stage-by-stage breakdown, it helps to understand the three projects we will reference throughout this article. Each represents a different scale and complexity of Class 2 development that giantA has delivered in the past three years.
| Project | Location | Scale | Scope | Approval Pathway | Total Timeline |
|---|---|---|---|---|---|
| Boutique Apartments | Merrylands | 12 units, 3 storeys | Demolition + new build | DA + CC | 38 weeks (concept to CC) |
| Mid-Rise Residential | Wentworthville | 24 units, 6 storeys | New build over basement parking | DA + CC | 52 weeks (concept to CC) |
| Mixed-Use Podium | Parramatta | 18 residential units + 2 commercial tenancies | New build, 8 levels | DA + CC | 61 weeks (concept to CC) |
Stage 1: Feasibility and Site Assessment (Weeks 1–4)
What Happens During Feasibility
The feasibility stage is where most project risks are either identified or missed. For the Merrylands project, a 12-unit, three-storey development on a 720 m² site, the feasibility phase took three weeks and uncovered two critical constraints that shaped the entire design approach.
First, the site contained a heritage-listated drainage easement running along the rear boundary. This was not immediately apparent from the title search and was only identified through a Section 10.7 planning certificate from Cumberland City Council. The easement reduced the buildable envelope by approximately 15%, which in turn affected the unit mix and basement parking layout.
Second, a preliminary BASIX assessment revealed that the site's east-west orientation would make the 7-star NatHERS thermal performance requirement more challenging to achieve without careful glazing selection and shading design. Engaging a BASIX consultant during feasibility — rather than waiting until DA documentation — saved approximately four weeks of redesign later in the process.
How Feasibility Timelines Compare
| Feasibility Factor | Merrylands (12 units) | Wentworthville (24 units) | Parramatta (Mixed-Use) |
|---|---|---|---|
| Duration | 3 weeks | 4 weeks | 5 weeks |
| Key constraint | Heritage drainage easement | Transport corridor setback | Mixed-use fire separation |
| Consultants engaged | BASIX consultant, town planner | BASIX, acoustic, traffic | BASIX, acoustic, fire engineer, access consultant |
| Cost | $4,500 | $8,200 | $12,000 |
| Risk identified that saved redesign | Easement reduced buildable area | Rail corridor noise required acoustic assessment | Class 2/5 separation needed 120/120/120 FRL floor |
Stage 2: Concept Design and Pre-DA Consultation (Weeks 4–12)
The Value of Pre-DA
Pre-DA (pre-Development Application) consultation is an optional but highly recommended step where a developer meets with council planners to discuss the proposed development before formal lodgement. For Class 2 projects, pre-DA can mean the difference between a 12-week DA assessment and a 24-week one.
For the Wentworthville project — a six-storey, 24-unit building — we lodged a pre-DA meeting request with City of Parramatta Council in week 5. The meeting was held in week 8, and the feedback directly shaped three design modifications:
The council indicated that the initial 24-unit yield was acceptable but expressed concerns about the depth of basement parking access from a sub-arterial road. The original design had a straight ramp from the street; the council preferred a turned entry to reduce vehicle conflict at the street boundary. This modification was incorporated before DA lodgement, avoiding a likely request for additional information (RFI) that would have added 4–6 weeks to the assessment.
Pre-DA also clarified the council's expectations regarding the Apartment Design Guide (ADG) compliance. SEPP 65 and the ADG prescribe minimum standards for apartment size, ceiling height, storage, and natural ventilation. The council confirmed that the deep soil zone requirement (minimum 7% of site area for 3+ storey developments) could be partially met through the rear setback where the drainage easement was located — but only if the landscaping plan demonstrated deep soil planting capable of supporting canopy trees.
Concept Design Deliverables
By the end of the concept design stage, a Class 2 project should have the following deliverables ready for DA lodgement preparation:
The design package typically includes site analysis drawings, existing condition plans, proposed floor plans for all levels, elevations, sections, a shadow analysis, a landscape concept plan, and a BASIX commitment summary. For regulated buildings under the DBP Act, the concept stage is also when the Registered Design Practitioner should begin documenting the regulated design elements — structural, fire safety, waterproofing, and building services — that will require compliance declarations later.
On the Merrylands project, the concept design was completed in five weeks (weeks 4–9), with pre-DA feedback received in week 7. The design was then refined for two weeks before moving to DA documentation. The total concept-to-DA-lodgement period was eight weeks, which is on the faster end of the spectrum for a 12-unit development.
The Parramatta mixed-use project took longer — ten weeks for concept design — because the architectural design needed to accommodate both residential and commercial floor plates, with a podium-level transition that addressed fire separation, acoustic separation, and accessibility requirements simultaneously.
Stage 3: DA Documentation and Lodgement (Weeks 10–20)
Documentation Scope for Class 2 DA
A Class 2 DA submission in NSW typically requires a comprehensive documentation set that goes well beyond what is needed for a single dwelling. The Statement of Environmental Effects alone for the Wentworthville project ran to 32 pages, addressing matters such as built form controls, landscape provision, parking provision, solar access to adjoining properties, and consistency with the Apartment Design Guide.
The documentation set for each of the three projects is summarised below. Note the increasing complexity from a straightforward low-rise residential project to a mixed-use development.
| Document | Merrylands (12 units) | Wentworthville (24 units) | Parramatta (Mixed-Use) |
|---|---|---|---|
| Architectural drawings | 12 sheets | 22 sheets | 28 sheets |
| Statement of Environmental Effects | 18 pages | 32 pages | 41 pages |
| BASIX Certificate | 1 (multi-dwelling) | 1 (multi-dwelling) | 1 (multi-dwelling) |
| Acoustic report | Not required | Required (rail corridor) | Required (mixed-use) |
| Traffic/parking report | Not required | Required | Required |
| Fire safety report | Concept-level | Concept-level | Detailed (mixed-use) |
| Arborist report | Required (1 tree) | Required (3 trees) | Required (5 trees + heritage) |
| Heritage report | Not required | Not required | Required (heritage item adjacent) |
| Cost (+GST) | $48,000 | $95,000 | $135,000 |
DA Assessment Timeline: What Actually Happens
The statutory assessment timeframe for a DA in NSW is 28 days for designated local development, but this is routinely exceeded. In practice, the assessment period depends on the council's workload, the complexity of the proposal, and whether the proposal triggers notification to neighbours or referral to a panel.
For the Merrylands project, the DA was lodged in week 10 and determined in week 18 — a total of eight weeks. This was relatively fast because the pre-DA process had resolved the major issues, the proposal complied with all LEP controls, and no submissions were received during the notification period.
The Wentworthville DA took 14 weeks (lodged week 12, determined week 26). Two factors extended the assessment: first, the project was located within 50 metres of a rail corridor, requiring referral to Transport for NSW under the Transport and Development SEPP. Second, two neighbour submissions were received, requiring the council planning officer to prepare a submission assessment report. Neither submission raised issues that could not be addressed through conditions, but the process added four weeks.
The Parramatta DA took 18 weeks (lodged week 15, determined week 33). The mixed-use nature of the development triggered a Sydney Local Planning Panel (SILPP) referral because the project exceeded $5 million in capital investment value. The panel meeting added six weeks to the timeline, and an additional four weeks was spent responding to a request for additional information from the council's urban design team regarding the podium treatment and street activation.
Lessons from DA Assessment Delays
The most common cause of DA delays in our experience is incomplete documentation at lodgement. A DA that is missing a required report — for example, an acoustic assessment for a site near a rail corridor, or a flood study for a site in a flood-controlled area — will be placed on hold within the first two weeks of assessment and will not recommence until the missing information is provided. This can add 4–8 weeks.
Our recommendation is to prepare a documentation checklist specific to the site and council before lodgement. Every council in NSW publishes a DA guide that lists required attachments; these guides should be reviewed for the specific LGA, as requirements vary between councils even for the same building type.
Stage 4: Construction Certificate and DBP Act Compliance (Weeks 20–38)
The CC Stage Under the DBP Act
The Construction Certificate (CC) stage is where the Design and Building Practitioners Act has its most significant practical impact. Under the DBP framework, the following regulated designs must be prepared, declared by a Registered Design Practitioner, and lodged on the NSW Planning Portal before a CC can be issued:
For Class 2 buildings, regulated designs include structural engineering designs, fire safety designs (including fire-resistance levels and fire safety systems), waterproofing designs, and building services designs (mechanical, electrical, hydraulic). Each regulated design must be accompanied by a compliance declaration from the responsible practitioner, and a building practitioner must lodge the complete set on the Planning Portal.
This is a substantial administrative and technical process that does not exist for Class 1 buildings. The CC stage for a Class 2 project typically takes 12–20 weeks, compared to 4–8 weeks for a Class 1a dwelling.
CC Timelines Across the Three Projects
| CC Stage Element | Merrylands (12 units) | Wentworthville (24 units) | Parramatta (Mixed-Use) |
|---|---|---|---|
| Duration | 12 weeks | 16 weeks | 20 weeks |
| Regulated design types | 4 | 6 | 8 |
| Compliance declarations lodged | 7 | 12 | 18 |
| Design practitioners engaged | 2 | 4 | 5 |
| Principal design practitioner | giantA (RDP) | giantA (RDP) | giantA (RDP) |
| Key challenge | Waterproofing specification coordination | Fire engineering performance solution | Mixed-use fire separation + access |
How DBP Act Compliance Affects Timeline
The DBP Act adds a coordination overhead that developers who have not previously built Class 2 buildings may not anticipate. Each compliance declaration requires the design practitioner to review the design against the BCA, confirm compliance, and submit the declaration through the Planning Portal. If a design needs revision after the declaration is lodged, a new declaration must be prepared and lodged.
On the Wentworthville project, the fire engineering performance solution for the boundary wall required three iterations before the certifier was satisfied. Each iteration required a new compliance declaration from the fire safety design practitioner, adding approximately two weeks per iteration. The lesson here is that performance solutions should be fully resolved and peer-reviewed before the compliance declaration is lodged — not iterated during the CC assessment.
The NSW Government's Building Commission has indicated that DBP Act compliance is not a box-ticking exercise. Declarations are reviewed, and practitioners who lodge incomplete or non-compliant declarations face disciplinary action. This is why we treat the regulated design phase as a separate workstream with its own quality assurance process, rather than trying to fold it into the architectural documentation.
Stage 5: Pre-Construction Coordination (Weeks 36–40)
Bridging the Gap Between CC and Construction
Once the CC is issued, there is typically a 2–4 week period before construction commences during which the builder finalises the construction methodology, site establishment plans, and any residual documentation. For Class 2 buildings, this period also includes the builder's review of the regulated designs to ensure constructability.
On the Merrylands project, the builder identified a conflict between the structural engineer's slab design and the hydraulic engineer's drainage layout during pre-construction review. The conflict required a design revision and a new structural compliance declaration, which added one week. This is a common scenario — the builder's perspective on constructability often surfaces issues that were not apparent during the design phase.
Our approach is to involve the builder (or at minimum, a construction consultant) in the CC documentation review at week 32–34, before the CC is issued. This early review has consistently reduced pre-construction variations by 30–40% across our projects. The cost of engaging a construction consultant for a two-week documentation review — typically $3,000–$5,000 — is insignificant compared to the cost of design revisions after the CC is issued.
Comparing the Full Timeline Across Projects
The following table consolidates the full design-to-approval timeline for all three projects, showing how duration and cost scale with project complexity.
| Stage | Merrylands (12 units) | Wentworthville (24 units) | Parramatta (Mixed-Use) |
|---|---|---|---|
| Feasibility | 3 weeks / $4,500 | 4 weeks / $8,200 | 5 weeks / $12,000 |
| Concept + Pre-DA | 5 weeks / $18,000 | 8 weeks / $35,000 | 10 weeks / $42,000 |
| DA Documentation | 4 weeks / $48,000 | 6 weeks / $95,000 | 5 weeks / $135,000 |
| DA Assessment | 8 weeks / $0 | 14 weeks / $0 | 18 weeks / $0 |
| CC Documentation + DBP | 12 weeks / $72,000 | 16 weeks / $145,000 | 20 weeks / $210,000 |
| Pre-construction | 2 weeks / $0 | 4 weeks / $0 | 3 weeks / $0 |
| Total (concept to CC) | 34 weeks / $142,500 | 52 weeks / $283,200 | 61 weeks / $399,000 |
| Construction cost (excl. fees) | $3.2M | $7.8M | $9.6M |
| Professional fees as % of build | 4.5% | 3.6% | 4.2% |
What Developers Should Take Away
The single most important factor in controlling the design-to-approval timeline for a Class 2 project is early engagement of the right consultants. Every week saved at feasibility and concept stage — through early identification of constraints and early council engagement — compounds through the project. A four-week saving at pre-DA is typically a four-week saving at DA assessment, because the design that goes in has already been tested against council expectations.
The second most important factor is DBP Act compliance readiness. Developers who treat the regulated design and compliance declaration process as an afterthought consistently add 6–10 weeks to their CC stage. The practitioners who prepare these designs need to be engaged early, briefed thoroughly, and given time to prepare quality documentation. Rushing compliance declarations leads to iterations, and each iteration costs time.
Finally, the data from these three projects shows that professional fees for Class 2 development in Sydney range from approximately 3.5% to 4.5% of the construction cost for design and approval documentation. This is lower than the 8–15% figure sometimes quoted for full architectural services, because it excludes contract administration and construction phase services. Developers should budget for the full 8–15% if they want the design practitioner involved through construction — and for Class 2 buildings, we strongly recommend this involvement, because the regulated design compliance obligations extend into the construction phase.
FAQ
How long does it take to get DA approval for a Class 2 apartment building in NSW?
DA approval for a Class 2 apartment building in NSW typically takes 8 to 18 weeks from lodgement, depending on council workload, site constraints, and whether the proposal requires panel referral or inter-agency consultation. Projects near rail corridors, flood zones, or heritage items can take 14–20 weeks due to mandatory referrals. Pre-DA consultation can reduce this by 4–6 weeks.
Do I need a Registered Design Practitioner before lodging a DA for a Class 2 building?
No — a Registered Design Practitioner is not legally required at DA lodgement. However, the DBP Act requires regulated designs and compliance declarations before a Construction Certificate can be issued. Engaging an RDP during concept design (before DA) is strongly recommended, as it ensures the design is BCA-compliant from the outset and avoids costly redesigns at CC stage.
What is the difference between DA and CC for a Class 2 building?
A Development Application (DA) assesses whether the proposed use and built form comply with planning controls (LEP, DCP, SEPP 65). A Construction Certificate (CC) certifies that the detailed construction documentation complies with the Building Code of Australia and all conditions of the DA consent. For Class 2 buildings, the CC stage also requires regulated design declarations under the DBP Act, which adds 8–12 weeks compared to Class 1 buildings.
How much does design and approval cost for a Class 2 apartment development in Sydney?
Professional design and approval costs for a Class 2 apartment development in Sydney typically range from $142,000 for a 12-unit low-rise project to $399,000 for a mixed-use mid-rise development. This represents approximately 3.5–4.5% of the construction cost. Full architectural services through construction phase increase this to 8–15% of the construction cost.
Can a CDC be used instead of a DA for a Class 2 apartment building?
Generally, no. Complying Development Certificates for multi-dwelling housing are available under the State Environmental Planning Policy (Exempt and Complying Development Codes) 2008, but most Class 2 apartment buildings exceed the CDC thresholds for height, site area, or dwelling count. Class 2 buildings typically require a DA through the local council. The exception is certain low-rise dual-occupancy configurations that meet the Class 1a criteria.
What happens if a regulated design needs to change after the CC is issued?
If a regulated design is changed after the Construction Certificate is issued, the change must be documented, a new compliance declaration must be prepared by the relevant Registered Design Practitioner, and the revised design must be lodged on the NSW Planning Portal. Major changes may require a new CC or a Section 4.55 modification to the DA. This is why design coordination before CC lodgement is critical — post-CC design changes are the most expensive and time-consuming variations on a Class 2 project.
Does the DBP Act apply to renovations of existing Class 2 buildings?
Yes. The DBP Act applies to all building work on existing Class 2 buildings where the work involves a building element or performance solution. This includes alterations, repairs, and renovations. The same registration and declaration requirements apply as for new Class 2 buildings. Strata owners undertaking remedial work should engage a Registered Design Practitioner early in the scope definition process.
How does the Apartment Design Guide (ADG) affect the DA timeline?
The Apartment Design Guide, issued under SEPP 65, prescribes detailed standards for apartment size, ceiling height, storage, solar access, ventilation, and landscape provision. Non-compliance with the ADG is a common reason for DA delays, as council planners will issue requests for additional information if the ADG compliance assessment is incomplete. Preparing a comprehensive ADG compliance table as part of the DA documentation can reduce assessment time by 2–4 weeks.
About the Author
Franz Phan is a Registered Design Practitioner under the NSW Design and Building Practitioners Act 2021, specialising in Class 2 and multi-residential building design. With over 15 years of experience in the NSW construction industry, Franz has delivered more than 40 apartment developments across Greater Sydney, ranging from boutique low-rise projects to mixed-use mid-rise developments. He holds registrations for both low-rise and medium-rise building design under the DBP scheme and is a member of the Building Designers Association of Australia.
Sources
1. NSW Government, "Building classes and roles of professionals under the Design and Building Practitioners scheme" — https://www.nsw.gov.au/housing-and-construction/compliance-and-regulation/professionals-working-on-regulated-buildings/building-classes-and-roles
2. NSW Government, "Fees for design and building practitioner registrations" (updated 1 July 2026) — https://www.nsw.gov.au/business-and-economy/licences-and-credentials/building-and-trade-licences-and-registrations/assessment-process-and-time-frames/fees-for-registration
3. Design and Building Practitioners Act 2020 (NSW) — https://legislation.nsw.gov.au/view/html/inforce/current/act-2020-007
4. National Construction Code, Volume One, Building Classification — https://ncc.abcb.gov.au/ncc-navigator/building-classifications
5. NSW Planning Portal, "BASIX — Building Sustainability Index" — https://www.planningportal.nsw.gov.au/development-and-assessment/basix
6. State Environmental Planning Policy No 65 — Design Quality of Residential Apartment Development (Apartment Design Guide) — https://www.planning.nsw.gov.au/policy-and-legislation/housing-and-development/codes-and-policies