Class 2 buildings
New and existing class 2 buildings, including mixed-use buildings with a class 2 part, commonly fall within the DBP framework for relevant building work.
NSW waterproofing process, regulated designs and responsibility boundaries
Waterproofing NSW: Process, DBP Act Roles and Façade Interfaces
Waterproofing requirements in NSW depend on the building, scope, approval pathway and appointed practitioner roles. Where the Design and Building Practitioners scheme applies, waterproofing may require regulated designs, declarations and lodgements before relevant building work starts.
Start With Building Class, Scope and Timing
The DBP Act does not apply identically to every waterproofing project. The first review should identify the building classification, whether the work is new or remedial, the affected building element, any performance solution, applicable exclusions and whether the work is an emergency.
Current NSW guidance confirms that the scheme applies to building work on new and existing class 2 buildings. Certain new class 3 and 9c work is also regulated, while alteration, repair and renovation work on existing class 3 and 9c buildings is currently deferred until 1 July 2028.
Review the current NSW Government guidance on regulated building classes and practitioner roles.
Waterproofing can remain captured even where work appears to be exempt development. The specific exclusions in the DBP Regulation must be checked rather than assumed.
When Waterproofing May Require Regulated Designs
Waterproofing is one of the building elements identified by the NSW scheme. Where captured work involves that element, the required construction-ready design and declaration pathway should be established before the relevant work begins.
Class 3 and 9c buildings
Certain new work is regulated. Current NSW guidance defers alteration, repair and renovation work on existing class 3 and 9c buildings until 1 July 2028.
Building elements
Waterproofing, building enclosure, structure, fire-safety systems and certain required building services are defined building elements.
Performance solutions
A performance solution can trigger regulated-design requirements even where the work is not otherwise obvious from the trade description.
Exclusions
Low-value, exempt-development, maintenance and single-dwelling waterproofing exclusions are conditional. Each condition must be satisfied.
Emergency work
Emergency remedial work has a separate process. Urgency should not be used to bypass the statutory pathway where the emergency criteria are not met.
See the NSW Government’s current remedial building work guidance before relying on an exclusion or emergency pathway.
Regulated Designs, Declarations and Lodgements
Where the DBP scheme applies, the waterproofing design should contain enough detail for the building work to be carried out in accordance with the Building Code of Australia. The design should integrate relevant substrates, falls, drainage, joints, penetrations, upturns, terminations and adjoining building elements.
- An appropriately registered design practitioner prepares the regulated design.
- The design practitioner provides the required design compliance declaration within their authorised class.
- The appointed building practitioner lodges the required design and declaration before the relevant building work starts.
- Changes affecting a building element or performance solution may require revised designs and declarations before varied work continues.
- Construction and close-out records should correspond with the approved and lodged information.
Review the NSW Government’s design practitioner obligations for the current requirements.
Waterproofing Construction Process
The approved design and product requirements control the exact sequence. A typical process includes the following project-specific stages.
Scope review
Confirm the defect, building class, approvals, design responsibilities and access.
Substrate preparation
Remove unsuitable materials and repair, clean, dry and prime the substrate as specified.
Detail interfaces
Treat joints, cracks, penetrations, drains, upturns, thresholds and transitions.
Apply the system
Install the specified membrane, reinforcement and protection to the required coverage and thickness.
Inspect and test
Complete the approved hold points, checks, tests, photographs and defect rectification.
Protect and hand over
Protect completed work and provide the agreed records, limitations and maintenance information.
The NCC does not create one universal waterproofing hold point for every project. Inspection and testing requirements must come from the applicable design, specification, product system, inspection and test plan, contract and certification pathway.
Who Is Responsible for What?
| Party | Typical responsibility | Important boundary |
|---|---|---|
| Owner or owners corporation | Provides records, appoints the required parties and makes project, funding and access decisions. | Should not assume the contractor can replace independent design, certification or legal advice. |
| Design practitioner | Prepares and declares regulated designs within the practitioner’s authorised registration class. | Responsible for the declared design, not the contractor’s workmanship. |
| Building practitioner | Agrees to carry out or oversee regulated building work and completes the required design and building lodgements. | There is one building practitioner or principal contractor for the regulated project. |
| Waterproofing contractor | Completes the agreed trade work in accordance with the current design, product and quality requirements. | Trade delivery does not automatically make the contractor the design practitioner or certifier. |
| Certifier or authority | Performs the certification, approval, inspection or statutory functions assigned to that role. | Does not replace the contractor’s construction responsibility or the designer’s declared design responsibility. |
| SCE Corp | Delivers and coordinates the contracted construction scope and can act within an appointed DBP building-practitioner role where the contract and registration permit. | SCE’s precise responsibility depends on whether it is appointed as building practitioner, principal contractor or another construction participant. |
SCE Corp is NSW DBP registered. SCE ensures the construction work within its contracted control follows the approved regulated designs, declarations, specifications, approvals and project requirements. Consultant, design-practitioner, certifier and statutory responsibilities remain with the appropriately appointed parties.
Façade Waterproofing and Interface Risks
Façade waterproofing may involve coatings, membranes, flashings, sealants and drainage details. The visible external surface is only one part of the building enclosure.
- window and door perimeters, sill and head flashings;
- balconies, thresholds, outlets and balustrade penetrations;
- parapets, roofs, cappings and overflow paths;
- cladding joints, membranes, cavities and transitions;
- movement joints, cracks and sealant geometry;
- services, anchors and other façade penetrations; and
- substrate deterioration, corrosion and concealed moisture.
Where the issue is primarily façade sealing, interface maintenance or leak investigation, review the supporting Waterproofing and Façade Sealing guide.
Warranties, Duty of Care and Project Records
Statutory warranties under the Home Building Act apply to applicable residential building work. Current NSW guidance states that the warranty period is six years for major defects and two years for other defects. Waterproofing is a major element, but the statutory major-defect test still needs to be satisfied for the longer period to apply.
The DBP Act’s statutory duty of care is separate. It concerns reasonable care to avoid economic loss caused by defects arising from construction work. Contract warranties, product warranties, statutory warranties and duty-of-care claims should not be treated as interchangeable.
Review the NSW Government’s current statutory warranty guidance and obtain legal advice where rights, limitation periods or liability are material.
Project records should identify the approved design, products, substrates, preparation, application, inspections, tests, variations, concealed-work evidence, defects, handover information and maintenance requirements.
Waterproofing NSW and DBP Act FAQs
When may the NSW DBP Act apply to waterproofing work?
The answer depends on the building class, whether the work is new, remedial, alteration or repair work, whether waterproofing is a building element involved in the scope, and whether an exclusion or emergency pathway applies. Existing class 2 and mixed-use buildings with a class 2 part are commonly captured. Current NSW guidance should be checked for class 3 and 9c timing and exclusions.
Which buildings and waterproofing scopes may be regulated?
The NSW scheme currently regulates class 2 buildings and certain class 3 and 9c work. Waterproofing can be a regulated building element where the work falls within the scheme. Alteration, repair and renovation work on existing class 3 and 9c buildings is currently deferred until 1 July 2028. Project-specific classification and scope review remain necessary.
What are regulated designs and compliance declarations?
A regulated design is construction-ready design information for a building element or performance solution on a regulated building. An appropriately registered design practitioner prepares the design and provides the required design compliance declaration. The appointed building practitioner is responsible for lodging the required documents before the relevant work starts.
What are the respective practitioner and contractor responsibilities?
The owner or owners corporation appoints the required parties. Design practitioners prepare and declare regulated designs within their registration. The appointed building practitioner carries out or oversees regulated building work and completes the required lodgements. Waterproofing contractors deliver their agreed trade scope. Certifiers and authorities perform their separate statutory functions.
Are waterproofing inspections and hold points mandatory?
Inspection and hold points should be defined by the approved design, specification, manufacturer requirements, inspection and test plan, contract and applicable certification pathway. It is inaccurate to describe every waterproofing inspection as a universal NCC hold point. Concealed work should not proceed until the required project-specific checks and records are complete.
What is the difference between façade waterproofing and façade sealing?
Façade waterproofing may involve membranes, coatings, flashings and complete external-envelope details intended to resist water penetration. Façade sealing usually addresses joints, penetrations and interfaces. Both require investigation of the water path, substrate, movement, exposure and compatibility before a repair system is selected.
How do statutory warranties and the DBP duty of care differ?
Statutory warranties arise under the Home Building Act for applicable residential building work and generally run for six years for major defects and two years for other defects. Waterproofing is a major element, but not every waterproofing defect automatically satisfies the major-defect test. The DBP statutory duty of care is a separate legal obligation relating to economic loss caused by construction defects.
What information should be provided for an SCE review?
Provide the property address, building class where known, drawings, reports, photographs, leak history, existing waterproofing information, approvals, notices, access constraints, occupancy requirements, urgency, programme and required outcome. SCE will assess whether the construction and coordination scope is suitable and which consultant or practitioner inputs may be required.
Provide the Building, Waterproofing and DBP Information
Send the property address, building class where known, drawings, reports, photographs, leak history, notices, approvals, existing waterproofing information, access constraints, occupancy requirements, urgency, programme and required outcome.