Class 2 Apartment Building Design NSW 2026: DBP Act Compliance Guide for Developers & Architects

Author: Franz Phan, Senior Planning Consultant, giantA Pty Ltd Published: July 16, 2026 Reading Time: 14 minutes

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Executive Summary

Class 2 apartment buildings in NSW now operate under the most tightly regulated design framework in Australian history. The Design and Building Practitioners Act 2020 (DBP Act) mandates that every structural, waterproofing, and fire-safety design for a Class 2 building must be prepared by a registered design practitioner and lodged as a regulated design on the NSW Planning Portal before construction begins. On 6 May 2026, the NSW Government introduced the Building (Approvals and Practitioners) Bill 2026, which proposes to fold the DBP Act into a unified digital approvals system while maintaining — and in some respects strengthening — practitioner registration requirements. For developers and architects, this means compliance is no longer a post-design formality; it is embedded in the earliest sketch-planning stages. This guide explains the current DBP Act obligations, the proposed 2026 legislative changes, and the practical steps required to deliver a compliant Class 2 apartment project in NSW.

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1. What Is a Class 2 Building Under the BCA and DBP Act?

A Class 2 building is defined in the National Construction Code (NCC) Volume One as a building containing two or more sole-occupancy units, each being a separate dwelling. In practical terms, this means apartment buildings, multi-unit residential flat buildings, and mixed-use developments where the residential component is self-contained.

The DBP Act currently regulates three building classes:

Why does the DBP Act single out Class 2? The regulatory focus on Class 2 buildings stems from the systemic quality failures exposed during the 2017–2020 NSW building defect crisis, particularly the Opal Tower and Mascot Tower incidents. Apartments were found to have inadequate structural design documentation, waterproofing defects, and fire-safety non-compliances that were not discovered until post-occupancy. The DBP Act was enacted specifically to ensure that every critical design element for these buildings is traceable to a registered, accountable practitioner.

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2. Who Must Register Under the DBP Act?

The DBP Act creates three categories of registered practitioners who must be engaged on any Class 2 project involving regulated building work:

2.1 Design Practitioners

A design practitioner is any person who prepares a regulated design for a Class 2 building. "Regulated design" means a design for a building element (structure, enclosure, fire safety, waterproofing) or a performance solution. Under Schedule 1 of the DBP Regulation, design practitioners are classified by authorised work type:

Registration requirements: Design practitioners must hold a current registration with the NSW Building Commission, demonstrate a record of experience in their class, and maintain professional indemnity insurance of at least $1 million per claim.

2.2 Building Practitioners

A building practitioner is the person who carries out building work on a Class 2 building under a regulated design. The building practitioner must hold a current builder licence from NSW Fair Trading and be registered under the DBP Act for the relevant class of work.

2.3 Principal Design Practitioners

For complex or multi-disciplinary projects, a principal design practitioner (PDP) must be appointed. The PDP coordinates all regulated designs, reviews them for consistency, and lodges the consolidated design compliance declaration on the NSW Planning Portal. The PDP is the single point of accountability for design integrity.

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3. The Regulated Design Workflow: Step-by-Step

For developers and architects unfamiliar with the DBP Act, the regulated design process can appear bureaucratic. In practice, it is a structured workflow that, if managed correctly, runs parallel to the normal design development timeline without adding significant delay.

Step 1: Engage Registered Practitioners at Concept Stage

Direct answer: Do not wait until development application (DA) lodgement to engage your design practitioners. The DBP Act requires regulated designs to be prepared and declared before building work commences, and many councils now request design compliance declarations at DA stage.

Expanded guidance: At giantA, our standard practice is to engage the structural engineer, fire safety engineer, and waterproofing consultant during the concept design phase (RIBA Stage 2). This allows the regulated design requirements to inform the architectural geometry rather than forcing retrospective changes. For a typical 20-unit apartment building in Sydney, early engagement adds approximately $8,000–$12,000 in upfront consultant fees but avoids redesign costs that can exceed $40,000 if regulated designs are prepared after the architectural scheme is fixed.

Step 2: Prepare Regulated Designs

Each design practitioner prepares their regulated design in accordance with the NCC, Australian Standards, and the DBP Regulation. The design must include:

- Drawings showing compliance with the Performance Requirements or a Deemed-to-Satisfy Solution - Specifications for materials, systems, and installation methods - A design compliance declaration (DCD) signed by the registered practitioner

Step 3: Principal Design Practitioner Review

The PDP reviews all regulated designs for consistency and completeness. The PDP must be satisfied that:

- No design conflicts exist between disciplines (e.g., structural penetrations through fire-rated compartments) - All Performance Solutions have been justified by a registered professional engineer - The designs comply with the NCC and any applicable State Environmental Planning Policies (SEPPs)

Step 4: Lodge on the NSW Planning Portal

The PDP lodges the regulated designs and DCDs on the NSW Planning Portal under the project’s development application or construction certificate. The portal assigns a unique reference number to each regulated design, creating a permanent audit trail.

Step 5: Building Practitioner Acknowledgement

Before construction begins, the building practitioner must acknowledge on the portal that they have received and understood the regulated designs. This creates a statutory link between the design intent and the construction execution.

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4. The Building (Approvals and Practitioners) Bill 2026: What Changes?

On 6 May 2026, the NSW Government introduced the Building (Approvals and Practitioners) Bill 2026. If enacted, this Bill will replace the current fragmented system — where the EP&A Act, DBP Act, and Building and Development Certifiers Act 2018 operate in parallel — with a single, digitally focused building approvals framework.

4.1 Key Proposed Changes

4.2 Impact on Class 2 Apartment Developers

The most significant change for developers is the proposed requirement for independent design review for all Class 2 buildings exceeding three storeys. Currently, independent review is only required for certain high-risk projects or where a performance solution is proposed. Under the Bill, every mid-rise and high-rise apartment project will require a secondary review by a registered practitioner who was not involved in the original design.

Cost impact: Independent design review fees typically range from $15,000 to $35,000 for a 20-unit, 4-storey apartment building. For a 100-unit, 8-storey building, expect $45,000 to $80,000. These costs are additive to the existing design practitioner fees.

Timeline impact: Independent review adds 3–6 weeks to the design development phase. Developers should factor this into their project schedules, particularly where construction finance drawdowns are tied to DA approval milestones.

4.3 Statutory Duty of Care Expansion

The Bill proposes to extend the statutory duty of care — currently owed by practitioners — to project directors and developers. This means that a developer who knowingly proceeds with a non-compliant design, or who fails to engage registered practitioners, could face personal liability for building defects. This is a profound shift in risk allocation and reinforces the need for developers to engage reputable design and construction teams.

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5. Approval Pathways for Class 2 Buildings in NSW

Class 2 apartment buildings cannot be approved via the Complying Development Certificate (CDC) pathway unless they meet very specific criteria under the State Environmental Planning Policy (Housing) 2021. In practice, almost all Class 2 buildings require a Development Application (DA) and Construction Certificate (CC).

5.1 DA vs CDC for Class 2 Buildings

Critical point: A "Class 2 building" under the BCA is not the same as a "residential flat building" under the SEPP. The SEPP uses different definitions and zones. Always confirm with your planning consultant whether your project triggers additional SEPP requirements (e.g., Design and Place SEPP, Apartment Design Guide).

5.2 The Construction Certificate Stage

After DA approval, a Construction Certificate (CC) is required before any building work can commence. Under the DBP Act, the CC application must include:

- All regulated designs lodged on the NSW Planning Portal - Design compliance declarations from each registered practitioner - A principal design practitioner declaration (if applicable) - A building practitioner acknowledgement

giantA case study: On a recent 16-unit apartment project in Auburn, we compressed the CC approval timeline from 10 weeks to 5 weeks by lodging all regulated designs on the portal at the same time as the CC application, rather than sequentially. The certifier was able to review the designs in parallel with the structural and BCA compliance checks, and no information requests were issued.

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6. Common Compliance Failures and How to Avoid Them

After five years of operating under the DBP Act, several recurring compliance failures have emerged. These are the issues that delay projects, trigger council information requests, and expose developers to liability.

6.1 Failure to Register All Design Practitioners

The mistake: A developer engages an architect and structural engineer but assumes the hydraulic engineer and fire safety engineer do not need to be registered because they are designing "secondary" systems.

The reality: Any design for a building element (structure, enclosure, fire safety, waterproofing) requires a registered practitioner. Hydraulic designs for roof drainage that interface with the enclosure system, or fire sprinkler layouts that penetrate fire-rated compartments, are regulated designs.

The fix: At the outset of every project, create a design practitioner register that lists every consultant, their DBP Act registration number, their authorised class, and the specific building elements they are designing. giantA maintains this register as a live document that is updated at each design stage.

6.2 Inconsistent Performance Solutions

The mistake: The architect proposes a Performance Solution for external wall fire spread (e.g., using a non-standard cladding system), but the fire safety engineer’s regulated design assumes a Deemed-to-Satisfy wall assembly.

The reality: The DBP Act requires that Performance Solutions are justified by a registered professional engineer and that all regulated designs are consistent. Inconsistent assumptions between disciplines will be flagged by the certifier or the principal design practitioner.

The fix: Hold a design integration workshop at the end of schematic design (RIBA Stage 3) where each consultant presents their compliance strategy and the PDP identifies conflicts. This workshop typically takes 2–3 hours and resolves 90% of inter-disciplinary issues before they become lodged designs.

6.3 Late Engagement of the Principal Design Practitioner

The mistake: The developer appoints the PDP after the regulated designs are already prepared, treating the PDP as an administrative signatory rather than a design coordinator.

The reality: The PDP’s role is to review designs for consistency, not merely to upload them to the portal. A PDP appointed late cannot effectively coordinate disciplines and is more likely to reject designs, causing delays.

The fix: Appoint the PDP at the same time as the architect, ideally before the concept design is developed. The PDP should be involved in the design integration workshop and should review draft designs before they are finalised as regulated designs.

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7. Cost Breakdown: Class 2 Apartment Design and Compliance

Understanding the full cost of DBP Act compliance is essential for accurate project feasibility. The following table summarises typical costs for a 20-unit, 4-storey apartment building in metropolitan Sydney.

Developer tip: These costs are tax-deductible as project development expenses. For GST-registered developers, the GST component is recoverable. Ensure your feasibility model captures these costs in the pre-construction phase, not as a post-DA surprise.

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8. Stakeholder-Specific Guidance

8.1 For Developers

- Budget conservatively: Add 15–20% to your design consultant allowance for DBP Act compliance costs, particularly if the project involves performance solutions or complex structural forms. - Engage early: The most expensive mistake is engaging design practitioners after the architectural design is fixed. Early engagement allows structural and fire-safety requirements to inform the design rather than constrain it. - Verify registrations: Check every consultant’s registration on the NSW Building Commission public register before issuing a letter of engagement. Unregistered practitioners cannot lodge regulated designs. - Plan for the Bill 2026: If your project will lodge a DA after late 2026, assume independent design review will be required and include it in your programme.

8.2 For Architects

- Understand the NCC Performance Requirements: The DBP Act does not introduce new technical standards; it enforces accountability for existing NCC requirements. Architects who already design to the NCC will find the DBP Act adds administrative workload, not technical complexity. - Coordinate with the PDP: Provide the PDP with clear design intent documentation (not just drawings) so they can verify that regulated designs align with the architectural vision. - Manage client expectations: Explain to developers that regulated designs are not an optional extra; they are a statutory requirement that carries personal liability for unregistered work.

8.3 For Builders

- Review regulated designs before tender: The DBP Act requires the building practitioner to acknowledge that they have received and understood the regulated designs. Review them during the tender phase, not after contract award. - Document variations: Any deviation from a regulated design during construction must be documented as a variation and re-lodged on the portal by the design practitioner. Failure to do so is a breach of the DBP Act. - Train site supervisors: Site supervisors must understand which elements are regulated (structure, enclosure, fire safety, waterproofing) and ensure that construction matches the lodged designs.

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9. FAQ: Class 2 Building Design and DBP Act Compliance

Q1: What is the difference between a Class 2 building and a Class 1a building? A: A Class 1a building is a single dwelling (detached house or one of a group of two attached dwellings, i.e., a duplex). A Class 2 building contains two or more sole-occupancy units, each being a separate dwelling — typically an apartment building. The DBP Act applies to Class 2, 3, and 9c buildings but not to Class 1a.

Q2: Does the DBP Act apply to renovations of existing Class 2 buildings? A: Yes. If the renovation involves regulated building work (structural changes, waterproofing replacement, fire safety upgrades), the work must be designed by a registered practitioner and lodged as a regulated design. Minor cosmetic renovations that do not affect building elements are exempt.

Q3: Can an unregistered architect prepare designs for a Class 2 building? A: No. Only architects who are also registered as design practitioners under the DBP Act can prepare regulated designs for Class 2 buildings. Architectural registration with the NSW Architects Registration Board does not automatically confer DBP Act registration. Always verify both registrations.

Q4: How long does it take to obtain a design practitioner registration? A: The NSW Building Commission typically processes applications within 6–10 weeks, provided the applicant submits a complete record of experience and evidence of professional indemnity insurance. Incomplete applications can take 4–6 months. Plan consultant engagement timelines accordingly.

Q5: What happens if a regulated design is changed during construction? A: Any change to a regulated design during construction requires a design variation to be prepared by the original design practitioner (or a replacement registered practitioner), signed with a new design compliance declaration, and re-lodged on the NSW Planning Portal. The building practitioner must acknowledge the variation before the changed work proceeds.

Q6: Is the Building (Approvals and Practitioners) Bill 2026 already law? A: No. The Bill was introduced to the NSW Parliament on 6 May 2026. As of July 2026, it is undergoing parliamentary review and consultation. If passed, it is expected to come into effect in late 2026 or early 2027. Developers should monitor the NSW Parliament website for updates but should continue to comply with the current DBP Act requirements.

Q7: Can a single person act as both the design practitioner and the building practitioner? A: In limited circumstances, yes. A person who holds both design practitioner registration and a builder licence can prepare regulated designs and carry out the building work, provided they are registered for the relevant class of work. However, they cannot act as the principal design practitioner for their own designs, as the PDP must provide independent coordination.

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10. Next Steps for Your Class 2 Project

If you are planning a Class 2 apartment development in NSW, the following checklist will help you navigate the DBP Act compliance requirements from concept to completion:

giantA’s Class 2 project experience: We have delivered 14 Class 2 apartment and mixed-use projects since the DBP Act came into effect in July 2021, ranging from 8-unit boutique developments in Marrickville to 45-unit mid-rise buildings in Parramatta. Our in-house planning and design coordination team manages the entire regulated design workflow, from practitioner engagement to portal lodgement, ensuring that compliance is seamless and that project timelines are protected.

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Conclusion

The DBP Act has transformed Class 2 apartment building design from a loosely supervised process into a tightly regulated, practitioner-accountable system. For developers and architects, this means higher upfront compliance costs but significantly lower risk of post-construction defects, litigation, and reputational damage. The proposed Building (Approvals and Practitioners) Bill 2026 will deepen this accountability by introducing independent design review and extending statutory duties to project directors.

The key to success is early engagement of registered practitioners, appointment of a competent principal design practitioner, and integration of the regulated design workflow into the normal design development timeline. Projects that treat the DBP Act as an afterthought will face delays, cost overruns, and compliance failures. Projects that embed it from the concept stage will deliver higher-quality buildings with defensible documentation.

Ready to discuss your Class 2 apartment project? 📞 Call giantA: +61 488 880 787 📧 Email: he@gianta.com.au 🌐 Free consultation: gianta.com.au/contact

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References:

1. NSW Government. (2026). *Design practitioner obligations when working on regulated buildings*. https://www.nsw.gov.au/housing-and-construction/compliance-and-regulation/professionals-working-on-regulated-buildings/design-and-building-practitioners/design-obligations 2. NSW Government. (2026). *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 3. Norton Rose Fulbright. (2026). *A new blueprint: New South Wales proposes to rewrite the rules on building approvals and modern construction*. https://www.nortonrosefulbright.com/en/knowledge/publications/eecc7fb4/new-south-wales-proposes-to-rewrite-the-rules-on-building-approvals-and-modern-construction 4. Australian Institute of Architects. (2021). *NSW Design and Building Practitioners Act and Regulation*. https://www.architecture.com.au/about/nsw-dbp-act-and-regulations 5. SafetyCulture. (2025). *A Guide to Class 2 Building Industry Reforms*. https://safetyculture.com/topics/class-2-building 6. Russell Kennedy. (2021). *New Rules for Designers and Builders in NSW*. https://www.russellkennedy.com.au/insights-events/insights/new-rules-for-designers-and-builders-in-nsw 7. Superb Maintenance Group. (2024). *DBP Act and Existing Class 2 Buildings: What Strata Owners Must Know*. https://superbmaintenancegroup.com.au/blog/dbp-act-existing-class-2-buildings 8. Bastian Architecture. (2024). *DBP Registration (Class 2, 3 + 9c Buildings)*. https://www.bastianarchitecture.com/class-23-registered