Waterproofing Design Practitioner Requirements Explained

Understanding Waterproofing Compliance Under the NSW DBP Act

Waterproofing defects remain one of the most common and costly issues affecting residential apartment buildings throughout New South Wales. In response to widespread building defects across the construction industry, the NSW Government introduced the Design and Building Practitioners Act 2020 (DBP Act), which established mandatory compliance requirements for regulated designs, including waterproofing systems.

For builders, developers, architects, remedial consultants and strata managers, understanding waterproofing Design Practitioner requirements is now essential for maintaining compliance on Class 2, 3 and 9c building projects.

This article explains when waterproofing declarations are required, what constitutes a regulated waterproofing design, and how the NSW DBP legislation applies to waterproofing works.

Why Waterproofing Is Regulated Under the DBP Act

Waterproofing failures are a major contributor to:

• water ingress,

• concrete deterioration,

• facade damage,

• mould growth,

• and long-term building defects.

Because of the high risk associated with waterproofing failures, waterproofing systems are considered regulated building elements under the NSW DBP legislation.

This means certain waterproofing designs must be:

• prepared by a registered Design Practitioner,

• declared through a Design Compliance Declaration,

• and lodged on the NSW Planning Portal before the relevant work commences.

What Is a Waterproofing Regulated Design?

A waterproofing regulated design generally relates to waterproofing systems associated with regulated building work under the DBP legislation.

This may include:

• balconies,

• rooftops,

• podium slabs,

• planter boxes,

• wet areas,

• terraces,

• retaining structures,

• basement waterproofing systems,

• and external membrane systems.

The design documentation typically includes:

• membrane systems,

• substrate preparation,

• falls and drainage requirements,

• termination details,

• flashing details,

• movement joints,

• and system compatibility requirements.

Which Buildings Require Waterproofing Declarations?

Waterproofing declaration requirements generally apply to:

• Class 2 buildings,

• mixed-use developments containing a Class 2 component,

• Class 3 buildings,

• and Class 9c buildings.

Examples commonly include:

• residential apartment buildings,

• seniors living developments,

• boarding houses,

• and aged care facilities.

Certain remedial projects involving waterproofing replacement or upgrades may also trigger DBP obligations.

Who Can Prepare a Waterproofing Regulated Design?

Waterproofing regulated designs must generally be prepared by a registered Design Practitioner with the appropriate registration class and experience relevant to the work being undertaken.

Depending on the project, this may include:

• architects,

• building designers,

• facade consultants,

• remedial consultants,

• or specialist waterproofing design practitioners.

The practitioner preparing the design is responsible for issuing the Design Compliance Declaration.

What Is a Waterproofing Design Compliance Declaration?

A Design Compliance Declaration is a declaration confirming that the regulated waterproofing design complies with:

• the Building Code of Australia,

• applicable Australian Standards,

• and relevant legislative requirements.

For waterproofing systems, this commonly involves consideration of:

• AS 4654.1 and AS 4654.2,

• NCC waterproofing requirements,

• manufacturer installation requirements,

• drainage design,

• and system compatibility.

The declaration forms part of the mandatory compliance documentation under the NSW DBP framework.

When Must Waterproofing Designs Be Lodged?

Regulated waterproofing designs and declarations must generally be lodged on the NSW Planning Portal before the relevant waterproofing work commences.

This is one of the most important practical obligations under the legislation.

Construction work involving regulated waterproofing systems should not proceed unless the required regulated designs and declarations have been properly prepared and lodged.

What Happens If Waterproofing Details Change During Construction?

Construction-stage changes are common and may affect waterproofing compliance obligations.

Examples may include:

• changes to membrane systems,

• revised falls and drainage,

• altered termination details,

• substrate changes,

• or revised facade interfaces.

Where a regulated waterproofing design changes, updated regulated designs and declarations may also be required prior to construction proceeding.

Proper variation management is critical for maintaining compliance during construction.

Waterproofing Compliance for Remedial Projects

The DBP legislation increasingly affects remedial building works involving waterproofing replacement and upgrades.

Common remedial projects include:

• leaking balconies,

• rooftop membrane replacement,

• podium waterproofing remediation,

• planter box leakage repairs,

• wet area remediation,

• and facade waterproofing upgrades.

Occupied Class 2 remedial projects often require extensive consultant coordination and staged construction sequencing to maintain compliance while minimising disruption to residents.

Common Waterproofing Compliance Issues

Some of the most common issues encountered on DBP projects include:

• incomplete waterproofing documentation,

• missing termination details,

• poor coordination between facade and membrane systems,

• undocumented site variations,

• inconsistent drainage design,

• and late-stage construction changes without updated declarations.

Proper coordination between consultants, contractors and Design Practitioners is essential for reducing compliance risk.

Why Waterproofing Documentation Is So Important

Waterproofing systems are highly dependent on:

• detailing,

• substrate preparation,

• drainage performance,

• workmanship,

• and system integration.

Even minor documentation inconsistencies can lead to significant long-term defects.

The DBP legislation aims to improve documentation quality and accountability throughout the construction process by requiring properly coordinated regulated designs and declarations.

How DBP Compliance Can Assist

DBP Compliance provides:

• waterproofing Design Practitioner services,

• regulated waterproofing design coordination,

• Design Compliance Declarations,

• remedial building compliance consultancy,

• and NSW Planning Portal assistance throughout New South Wales.

We assist builders, developers, architects, strata managers and remedial consultants in navigating the practical compliance requirements associated with waterproofing systems under the NSW Design and Building Practitioners legislation.

Need Assistance With Waterproofing DBP Compliance?

If you require assistance with:

• waterproofing regulated designs,

• Design Compliance Declarations,

• remedial waterproofing projects,

• NSW Planning Portal lodgements,

• or Principal Design Practitioner coordination,

contact DBP Compliance to discuss your project requirements.