Back to Insights DBPA

Navigating DBPA: Waterproofing Balconies

Balcony waterproofing failures remain one of the most common and costly defects in NSW apartment buildings. The Design and Building Practitioners Act 2020 (DBPA) was introduced to address systemic failures in the design and construction of residential buildings — and waterproofing sits squarely at the centre of its regulatory scope. If you are a builder, consultant, or strata manager involved in balcony waterproofing on Class 2 buildings, understanding the DBPA is no longer optional.

What Is the DBPA?

The Design and Building Practitioners Act 2020 (NSW) establishes a regulatory framework requiring that building work on certain classes of buildings is designed by registered design practitioners and carried out by registered building practitioners. It was a direct response to high-profile building defect crises in NSW, most notably the Opal Tower and Mascot Towers incidents in 2018–2019.

The Act applies to Class 2, Class 3, and Class 9c buildings — that is, multi-unit residential apartments, residential care buildings (boarding houses, hostels), and aged care facilities. It covers both new construction and, critically, remedial building work on existing buildings of these classes.

The core mechanism is straightforward: before building work begins, a registered design practitioner must prepare a regulated design and issue a design compliance declaration (DCD) confirming the design complies with the Building Code of Australia. A registered building practitioner must then carry out the work and declare it was completed in accordance with the declared design.

Why Waterproofing Is Specifically Targeted

Under the DBPA, waterproofing is classified as a building element — one of several critical components (alongside fire safety systems, structural elements, and building enclosures) that trigger the full regulatory requirements of the Act. This means any waterproofing work on a regulated building requires:

Waterproofing was given this elevated status because of the scale of defects associated with it. Water ingress through balconies, podiums, and rooftops accounts for a significant proportion of building defect claims in NSW strata buildings.

How This Applies to Balcony Waterproofing

Balcony waterproofing on Class 2 buildings is subject to the full DBPA framework. Whether the work is new construction or remedial re-waterproofing of an existing balcony, the process is the same:

1. Engage a Registered Design Practitioner

The design practitioner must be registered with NSW Fair Trading in an appropriate class of registration. For balcony waterproofing, the following classes are authorised to prepare regulated designs:

The practitioner must hold relevant experience and expertise in waterproofing, not merely hold the registration class. This is an important distinction that is sometimes overlooked.

2. Prepare the Regulated Design

The design must be a Construction-Issued Regulated Design (CIRD) — meaning it contains sufficient detail for a building practitioner to carry out the work in compliance with the BCA. For balcony waterproofing, the design should address:

For remedial work, the design should also include general elevations identifying which specific balconies are to be worked on, and general sections providing context and measurements.

3. Issue the Design Compliance Declaration

Under Section 8(1) of the DBPA, the design practitioner must issue a DCD confirming the design complies with the BCA, identifying any other standards or codes applied (AS 4654.1, AS 4654.2, NCC 2022), and confirming the practitioner has the qualifications and competence to prepare the design. The declaration must be lodged on the NSW Planning Portal before building work can commence.

4. Building Practitioner Carries Out and Declares the Work

A registered building practitioner must execute the waterproofing work in accordance with the declared design and then issue a building compliance declaration confirming the work is consistent with the design and compliant with the BCA.

What Triggers the Requirement

The DBPA requirements for balcony waterproofing are triggered when:

Importantly, even exempt development under the Codes SEPP is not automatically exempt from the DBPA when it involves waterproofing. Being exempt under planning rules does not exempt you from design declaration requirements. This catches many practitioners off guard.

The Section 37 Duty of Care

Beyond the declaration requirements, Section 37 of the DBPA imposes a statutory duty of care on anyone who carries out construction work. This duty requires the exercise of reasonable care to avoid economic loss caused by defects — and it extends to subsequent owners of the building, not just the original commissioning party. It is a non-delegable duty, meaning a head contractor cannot avoid liability by delegating waterproofing work to a subcontractor.

For balcony waterproofing, this has significant implications. Waterproofing failures that manifest years after completion can give rise to claims under Section 37, with liability extending back to all practitioners involved in the design and execution of the work.

Practical Implications for Builders and Consultants

Key Legislation and Standards References

The DBPA fundamentally changed how waterproofing work is delivered on apartment buildings in NSW. It is not merely a compliance exercise — it establishes clear accountability for the design and execution of work that, when done poorly, causes serious damage to buildings and the people who live in them. Practitioners who understand and work within this framework are better positioned to deliver durable outcomes and manage their professional risk.

Certified Waterproofing, in partnership with Excelo Engineering Consultants, provides DBPA-compliant waterproofing design, inspection, and consultancy services for Class 2 buildings across Sydney and NSW.