Back to Insights DBPA

When Is a Design Declaration Required?

One of the most frequent questions we receive from builders, strata managers, and building consultants is: do I actually need a design declaration for this waterproofing work? The answer depends on the building class, the nature of the work, and whether any specific exemptions apply under the Design and Building Practitioners Regulation 2021. This article sets out the thresholds clearly.

The Threshold: Class 2 and Above

The Design and Building Practitioners Act 2020 (DBPA) applies to building work on:

If the building falls into one of these classes, and the work involves a building element (which waterproofing is, by definition under the Act), then a design compliance declaration (DCD) is required.

This applies to both new construction and remedial work on existing buildings. There is no distinction — re-waterproofing a balcony on a 15-year-old apartment block triggers the same requirements as waterproofing a balcony on a building under construction.

What Counts as a "Building Element"

The DBPA defines building elements to include:

Waterproofing is not a peripheral concern under this legislation — it is listed alongside structural and fire safety systems as a critical building element requiring regulated design oversight.

Who Is a "Registered Design Practitioner" for Waterproofing?

Not every registered design practitioner can prepare waterproofing designs. The practitioner must be registered with NSW Fair Trading in an appropriate class of registration and hold relevant experience and expertise in waterproofing. The authorised classes for waterproofing work are:

A practitioner registered in, say, the electrical engineering class cannot prepare a regulated design for waterproofing, even if they have some knowledge of the subject. The registration class must align with the scope of the design work.

Equally important: registration alone is not enough. The practitioner must be able to demonstrate genuine competence in waterproofing design. Preparing a design outside one's expertise creates professional liability exposure under the Act and under the Section 37 duty of care.

What the Declaration Must Contain

A design compliance declaration under Section 8(1) of the DBPA must address:

The design itself must be a Construction-Issued Regulated Design (CIRD) — meaning it contains sufficient detail for a building practitioner to execute the work in compliance with the BCA. For waterproofing, this typically includes membrane specifications, substrate preparation requirements, fall details, junction and termination details, and reference to applicable Australian Standards.

Declarations must be completed on the current NSW Fair Trading form (updated January 2023), with one form per regulated design. The CIRD is lodged on the NSW Planning Portal by the building practitioner before work commences.

Common Misconceptions

"It's only maintenance, so we don't need a declaration."

There is no general maintenance exemption for waterproofing under the DBPA. If you are re-waterproofing a balcony, roof, or podium on a Class 2 building, the work involves a building element and requires a regulated design and declaration. The only narrow exemptions are set out in Clause 13 of the Regulation (discussed below).

"It's exempt development, so the DBPA doesn't apply."

This is one of the most dangerous assumptions in the industry. While exempt development under the Codes SEPP is generally excluded from DBPA requirements, waterproofing is the explicit exception. Being exempt under planning rules does not exempt waterproofing work from requiring a design declaration. The two regulatory frameworks must be assessed separately.

"Any engineer can sign off on waterproofing."

Only design practitioners registered in an authorised class (architectural, civil engineering, structural engineering, building design, or facade) can prepare waterproofing designs. An electrical or mechanical engineer, for example, is not authorised. And even within the authorised classes, the practitioner must hold relevant waterproofing expertise — not just a registration number.

"We only need a declaration for new builds."

Remedial waterproofing work on existing Class 2 buildings has been subject to the DBPA since the Act's commencement. This includes re-waterproofing works commissioned by strata bodies corporate, building managers, and individual lot owners where the work involves common property.

"The waterproofer can do the design."

A licensed waterproofing contractor (building practitioner) carries out the work and issues a building compliance declaration. But the design must be prepared and declared by a registered design practitioner. These are distinct roles under the Act. The waterproofer executes; the design practitioner designs and declares.

When You Do NOT Need a Declaration

Clause 13 of the Design and Building Practitioners Regulation 2021 sets out specific exemptions. For waterproofing, a declaration is not required when:

Note that Class 3 and Class 9c buildings are subject to the DBPA for new work now, with alteration and renovation work on existing buildings in these classes coming under the Act from 1 July 2026.

Practical Steps for Compliance

Key References

Getting the declaration question right at the outset avoids costly delays, potential stop-work orders, and long-term liability exposure. When in doubt, the conservative position is almost always the correct one: if the building is Class 2 or above and the work involves waterproofing, assume a declaration is required unless a specific Clause 13 exemption clearly applies.

Certified Waterproofing, in partnership with Excelo Engineering Consultants, provides DBPA-compliant waterproofing design declarations, inspections, and consultancy services across Sydney and NSW.