Waterproofing Certificate Guide for Western Australia
A waterproofing certificate is a legal document that confirms waterproofing work has been completed in accordance with Australian Standards (AS 3740-2021). In Western Australia, this certificate is a building compliance ...
A waterproofing certificate is a legal document that confirms waterproofing work has been completed in accordance with Australian Standards (AS 3740-2021). In Western Australia, this certificate is a building compliance requirement — your building certifier needs it before they can approve the wet area for tiling and subsequent use. Understanding waterproofing certificates helps you ensure your project meets WA requirements, protects you as a homeowner, and avoids problems when selling or insuring your property.
In This Guide
What Is a Waterproofing Certificate?
A waterproofing certificate is an official document issued by a licensed waterproofing contractor after completing waterproofing work. It certifies that the waterproofing membrane has been installed in accordance with AS 3740-2021, the manufacturer's specifications, and any applicable building approval conditions. The certificate typically includes the contractor's licence details, the property address, a description of the work performed, the membrane product used, flood test results, and the contractor's declaration that the work meets the standard. In WA, this certificate must be provided to the building surveyor (certifier) as part of the building approval process.
When Do You Need a Waterproofing Certificate in WA?
In Western Australia, a waterproofing certificate is required for all new construction that includes wet areas (bathrooms, showers, laundries), all renovations that involve waterproofing of wet areas, any remedial waterproofing work on existing buildings where a building permit is involved, and balcony waterproofing on new builds and major renovations. The certificate is a mandatory document for building approval. Without it, the building surveyor cannot approve the wet area for tiling, and the project cannot proceed to completion. This applies to both residential and commercial buildings.
What the Certificate Contains
A compliant waterproofing certificate in WA should contain the contractor's name, WA Building Commission registration number, and contact details. It should list the property address and the specific areas waterproofed, the membrane product name, manufacturer, and batch number, the method of application and number of coats, the date of application and the date the flood test was conducted, the flood test duration and results (pass or fail), and a declaration that the work complies with AS 3740-2021. Some contractors also include photographs of the completed membrane before tiling as additional evidence.
WA-Specific Legal Requirements
Western Australia has specific requirements for waterproofing certification that differ slightly from other states. The Building Services (Registration) Act 2011 requires that waterproofing work be carried out by a registered building service contractor. Only a registered contractor can issue a valid waterproofing certificate in WA. The WA Building Commission maintains a public register where you can verify a contractor's registration status. The Building Act 2011 gives the WA Building Commission authority to investigate complaints about non-compliant waterproofing and take disciplinary action against registered contractors who fail to meet standards.
What If You Do Not Have a Certificate?
If you purchased a property and the waterproofing certificate is missing, there are several steps to take. First, contact the original builder or waterproofing contractor to request a copy. Second, check with the local council or building surveyor who approved the construction — they may have the certificate on file. If no certificate can be found, it does not necessarily mean the waterproofing is defective, but it does mean compliance cannot be verified. This can be an issue when selling the property, making insurance claims, or if waterproofing problems develop. In this situation, a professional waterproofing inspection can assess the current condition of the waterproofing and provide a condition report. If the waterproofing has failed, remedial work with proper certification may be required.
Verifying a Waterproofing Certificate
To verify a waterproofing certificate in WA, check the contractor's registration on the WA Building Commission website (dmirs.wa.gov.au). Confirm the registration number on the certificate matches the public register. Verify the membrane product listed is an approved product with a current CodeMark or WaterMark certification. Check that a flood test was conducted and that the test duration meets AS 3740 requirements. If you have concerns about the validity of a certificate, you can contact the WA Building Commission for guidance or lodge a formal complaint.
WA Compliance Reminder
All waterproofing work in Western Australia must be performed by contractors registered with the WA Building Commission under the Building Services (Registration) Act 2011. We connect you with verified, licensed Perth waterproofing contractors who meet all WA compliance requirements.
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