Perth’s Leading Building & Pest Experts
Waterproofing Inspection & Compliance Assessment
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What Is a Waterproofing Inspection?
A waterproofing inspection assesses whether the waterproofing membranes and systems installed in a property have been correctly installed, are performing as intended, and comply with the relevant Australian Standards.
In Perth, waterproofing failures are one of the most common and costly building defects — and one of the most frequently disputed. WaterSafe Building Inspection provides independent waterproofing compliance assessments that give buyers, owners, builders, and strata managers clear answers about the condition and compliance of waterproofing installations.
- Bathrooms
- Laundries
- Balconies
- Podium decks
- Below-ground areas
WaterSafe Building Inspection provides independent waterproofing compliance assessments that give buyers, owners, builders, and strata managers clear answers about the condition and compliance of waterproofing installations.
Who is legally responsible for warranting the waterproofing for the next 10 years — the builder, or the subcontractors engaged by the builder?
In Western Australia, a separate waterproofing licence is not mandatory solely for carrying out waterproofing works; however, a builder’s licence is legally required for the overall building works and for accepting contractual responsibility for the waterproofing installation.
In the event of a waterproofing failure, the first question raised in any dispute is: “Was the waterproofing installed in accordance with AS3740 or AS4654?”
If any water-leaking issue or defect arises in the future, an Australian Standard compliance certificate will be requested before any warranty is considered or applied.
This is because the installation method must comply with the relevant Australian Standards, which are clearly mandatory under the NCC when the Deemed-to-Satisfy pathway is used.
In addition, most waterproofing membrane manufacturers’ warranties are only valid when the products are installed strictly in accordance with the manufacturer’s specifications and the applicable Australian Standards.
A WaterSafe waterproofing inspection provides the independent evidence you need — whether you’re a buyer assessing a property before purchase, an owner investigating an existing leak, or a builder seeking to demonstrate compliant installation.
Failure to provide evidence of compliant installation may result in both statutory warranty and manufacturer warranty being denied.
What a WaterSafe Waterproofing Inspection Covers
- Bathrooms — floors, shower bases, and wall-to-floor junctions
- Laundries — floor membranes and drainage zones
- Balconies and terraces — membrane condition, falls, and drainage
- Wet areas in commercial or strata buildings
- Below-ground waterproofing — retaining walls and basement areas (where accessible)
- Roof waterproofing — flat or low-pitch roofs with membrane systems
- Visible membrane condition — cracking, blistering, delamination, or deterioration
- Compliance with AS 3740 (internal wet areas) and AS 4654 (external waterproofing)
- Water test results — where applicable and agreed
- Compatibility of installed products with manufacturer specifications
- Evidence of compliant installation for warranty and dispute purposes
Is This Inspection Right for You?
Pre-Purchase Buyers Particularly for apartments, units, or properties with balconies or flat roofs.
Property Owners With an existing or suspected leak that requires professional investigation.
Builders & Developers Seeking an independent compliance report before handover.
Strata Managers Dealing with recurring water ingress complaints requiring documented evidence.
Owners in Dispute Disputing a builder's warranty claim or preparing for legal proceedings.
Frequently Asked Questions
What Australian Standards apply to waterproofing in Perth?
AS3740 applies to waterproofing of domestic wet areas (bathrooms, laundries, kitchens). AS4654.1 and AS4654.2 apply to external waterproofing membranes — including balconies, podium decks, and below-ground applications. Both standards are referenced in the NCC under the Deemed-to-Satisfy pathway.
Do I need a waterproofing inspection before buying a property?
Can a waterproofing inspection be used as evidence in a warranty dispute?
Yes. An independent inspection report from a licensed building practitioner documenting non-compliant installation or waterproofing failure can support warranty claims, insurance claims, or legal proceedings. We can provide a formal compliance assessment report for this purpose — ask us when you book.
How long does a waterproofing inspection take?
Typically 1–2 hours for a residential property, depending on the number of wet areas and accessible areas. Where water testing is agreed, additional time may be required.
Book a Waterproofing Inspection in Perth
Whether you’re buying a property, investigating a leak, or need a compliance report — WaterSafe Building Inspection provides independent, expert waterproofing assessments across Perth, Rockingham, and Mandurah.
Related Services:
→ Leak & Water Ingress Investigation
→ Pre-Purchase Building Inspection
Talk to Our Expert