DBP Act and Existing Class 2 Buildings: What Strata Owners Must Know

The Design and Building Practitioners Act 2020 (NSW) was enacted in response to systemic building quality failures in class 2 buildings across NSW. It created a registration framework for designers, engineers, and building practitioners, and established a statutory duty of care that extends to any person who carries out construction work. For owners corporations of existing class 2 buildings commissioning remedial work, the Act has direct and practical consequences.

What the DBP Act Does

The Design and Building Practitioners Act 2020 (NSW) operates across three main areas.

First, it creates a mandatory registration scheme for design practitioners, building practitioners, and professional engineers involved in class 2 building work. Practitioners must be registered with the NSW Building Commission and must prepare designs and declarations in a format specified by the Regulations.

Second, it requires that regulated designs be lodged on the NSW Planning Portal before construction commences and that the practitioner declare the design complies with the Building Code of Australia and the approved design documents.

Third, it creates a statutory duty of care owed by any person who carries out construction work to owners of land affected by that work. This duty exists whether or not there is a contract between the parties. It allows owners corporations to sue a designer or builder for negligent work even where there is no direct contractual relationship, and it applies to buildings on which construction work was carried out on or after 11 June 2020.

Registration Categories

The NSW Building Commission maintains a public register of all practitioners. There are three relevant registration types for strata remedial contexts.

Registered Design Practitioners

A registered design practitioner is authorised to prepare regulated designs for specified building classes and must lodge a design compliance declaration confirming that the design complies with applicable standards. The registration categories include:

• Architectural - overall building design, envelope, facade systems
• Structural engineering - structural design, element sizing, connection design
• Fire safety - active and passive fire system design
• Hydraulic - plumbing and drainage design
• Mechanical - HVAC and mechanical systems design

For remedial work on existing class 2 buildings, any design that modifies a fire-rated element, alters a structural element, or involves a waterproofing system over a certain area will require a registered design practitioner.

Registered Professional Engineers

A registered professional engineer (RPE) is registered in a specific discipline under the Building and Development Certifiers Act 2018 and the related rules. For structural and geotechnical work - the most consequential categories in remedial building - the engineer must hold current RPE registration.

Checking registration is straightforward. The NSW Building Commission's public register allows a search by name, company, and registration type. Do this before you engage any design professional for remedial work on a class 2 building.

Registered Building Practitioners

A registered building practitioner is authorised to carry out construction work for the relevant class of building. For class 2 remedial work involving regulated design elements, the building contractor must hold current registration. This is separate from the contractor's Building and Construction Industry Security of Payment Act obligations and separate from their Home Building Act licence.

Many experienced remedial contractors in Sydney hold both a contractor licence under the Home Building Act and registration under the DBP Act. The two are not the same. Verify both.

How the Duty of Care Applies to Existing Buildings

Part 4 of the DBP Act establishes a duty of care that applies to any person who carries out construction work from 11 June 2020 onwards. "Construction work" is defined broadly to include design, supervision, project management, and advice relating to building work, as well as the physical construction itself.

The duty is to exercise reasonable care to avoid economic loss caused by defects in or related to the building. The duty is owed to each owner of the land for which the construction work was carried out.

For an owners corporation, this means:

1. If remedial work was carried out on the building after June 2020, and that work was done negligently, the owners corporation can sue the designer or contractor under the DBP Act duty of care, even without a direct contract with that party.
2. The 6-year limitation period runs from when the loss first becomes apparent (or when it would have been apparent with reasonable diligence).
3. The duty covers both the initial construction and any subsequent construction work, including remedial work that was itself defective.

This has a practical implication for defective remedial work. If a previous contractor carried out waterproofing or concrete repair work after June 2020 and that work has failed, the owners corporation may have a claim under the DBP Act, independently of any contract claim.

What This Means When Commissioning Remedial Work

When an owners corporation engages a remedial contractor for class 2 building work, it should verify the following before works commence.

Step 1: Identify whether the work involves regulated designs. Structural work, fire-rated element alterations, and significant waterproofing systems will almost always involve regulated designs. The design must be prepared by a registered design practitioner in the relevant category, lodged on the Planning Portal, and accompanied by a compliance declaration.

Step 2: Verify practitioner registration. Check the NSW Building Commission register for each design practitioner and the building contractor. The check takes 5 minutes. Do it before executing any contract.

Step 3: Confirm the construction compliance declaration will be lodged. Before the building certifier issues an occupation certificate (or a sub-certificate for staged works), the builder must lodge a construction compliance declaration confirming that the work was carried out in accordance with the registered design. This document is important for the owners corporation's records and for any future SBBIS or legal proceedings.

Step 4: Retain all registration documentation. Keep copies of the registered designs, compliance declarations, and contractor registration certificates. These documents are evidence that the work was carried out within the regulatory framework and will be required in any future dispute.

The Class Expansion Roadmap

The DBP Act currently applies in full to class 2 buildings (residential apartment buildings). The NSW Government has indicated a roadmap for expanding requirements to additional building classes.

Class 3 buildings (residential hotels, motels, student accommodation, boarding houses) are the next category scheduled for expansion. The same registration and declaration requirements will apply to design and construction work on class 3 buildings when commencement is declared.

Class 9c buildings (aged care) are also on the expansion roadmap.

For owners and managers of these building classes, the practical implication is to begin engaging design practitioners and contractors who are already registered under the DBP framework, even before the legislative requirement takes effect. Practitioners who are not registered will need to obtain registration before they can legally carry out regulated design work once expansion occurs.

Monitor the NSW Building Commission website for commencement announcements.

Common Registration Errors in Remedial Projects

Our team has observed the following registration failures in remedial projects on Sydney strata buildings.

Using an unlicensed waterproofing contractor for complex roof membrane replacement. The contractor held a general builders licence but was not registered as a DBP building practitioner. The work required a regulated design that was never lodged.

Engaging a structural engineer who had not renewed their RPE registration. The engineer held current Engineers Australia membership but had allowed their NSW Building Commission RPE registration to lapse. The structural design they prepared could not be formally declared, delaying the project by 6 weeks.

Assuming a design and construct contract transfers all compliance risk to the contractor. The contractor's obligations under the DBP Act are their own, but the owners corporation's obligation to ensure the work is carried out by registered practitioners is not extinguished by the contract form. The owners corporation retains exposure if it knowingly engages an unregistered practitioner.

For guidance on the two-quotes process and scope of works requirements that apply when engaging these practitioners, see our Section 102 two-quotes rule guide. For the defect register obligations that sit alongside the DBP Act framework, see digital defects register requirements.

Across our 860+ projects, the buildings where remedial work has been most successfully completed are those where the owners corporation maintained a disciplined approach to practitioner registration from the outset. The cost of checking a registration is zero. The cost of unregistered work is compliance exposure, certification delays, and potential personal liability for committee members who approved the engagement.

References:

• Design and Building Practitioners Act 2020 (NSW)
• NSW Building Commission - Practitioner Registration
• Bannermans Lawyers - DBP Act Resources

The Bottom Line

The DBP Act exists because the old self-certification regime produced buildings with systematic defects. Registration requirements are not bureaucratic friction - they are the mechanism that ensures design practitioners stand behind their designs with legal accountability. An owners corporation that verifies registration before engaging a practitioner is not being difficult. It is protecting its legal position, ensuring the work can be certified, and ensuring that if the work fails, there is a registered practitioner who can be held accountable.