Waterproofing Certificate Guide: What Sydney Homeowners Need to Know
NSW does not have a government-issued waterproofing certificate. Here is what Sydney homeowners actually need to know about waterproofing documentation.
Last updated: 20 January 2026
What Is a Waterproofing Certificate?
A waterproofing certificate is a document issued by the waterproofing contractor confirming that the waterproofing work has been completed in accordance with AS 3740-2021 and the product manufacturer specifications. Unlike some other building certifications in NSW, there is no standardised government form for waterproofing certificates. Each waterproofing company issues their own certificate, which is why it is important to understand what a proper certificate should contain.
NSW-Specific Requirements
In NSW, waterproofing work on residential buildings must be performed by a contractor holding a licence issued by NSW Fair Trading. The contractor should issue a certificate of compliance upon completing the work. This certificate is not a government document but rather a trade certification provided by the contractor. The NSW Building Professionals Board and private certifiers may request this certificate as part of the building inspection process. For strata buildings in Sydney, the certificate is often required by the owners corporation and the strata manager.
Who Issues the Certificate?
The waterproofing certificate is issued by the licensed waterproofing contractor who performed the work. It is not issued by the council, NSW Fair Trading, or any government body. The contractor takes responsibility for the quality and compliance of the work through this certificate. If your builder or general contractor subcontracts the waterproofing, ensure the subcontractor issues the certificate directly — not the general contractor who did not perform the waterproofing.
What Should the Certificate Include?
A proper waterproofing certificate should include: the contractor’s name and NSW Fair Trading licence number, the property address and areas waterproofed, the date of completion, the membrane product used and manufacturer, a statement of compliance with AS 3740-2021, flood test results and duration, photographs of the completed membrane before tiling, the contractor’s signature, and warranty details. Any certificate missing these elements should be questioned.
When Do You Need a Certificate?
You need a waterproofing certificate whenever waterproofing work is performed on your Sydney property. This includes new construction, bathroom and laundry renovations, shower replacements, and remedial waterproofing repairs. The certificate is required for building sign-off by the certifier (PCA), for insurance claims, for strata records, and as documentation if you sell the property. Without a certificate, you may face difficulties with insurance claims, building compliance, and property sales.
What If You Did Not Receive a Certificate?
If your waterproofer did not provide a certificate, contact them immediately and request one. Under NSW Fair Trading guidelines, contractors should provide documentation of completed work. If the contractor refuses or is unavailable, you may need to engage a building inspector to assess the waterproofing and provide an independent report. For strata buildings, the owners corporation may require you to obtain a certificate before signing off on renovation work.
Keeping Your Certificate Safe
Store your waterproofing certificate with your other property documents. Keep digital and physical copies. The certificate is valuable for future insurance claims, property sales, warranty claims, and strata records. If you renovate again, the new waterproofer will need to know what was done previously. For strata properties in Sydney, provide a copy to your strata manager for the building records.
Waterproofing Certificate Guide FAQs
While NSW does not mandate a specific government-issued certificate, building certifiers require evidence of compliant waterproofing for sign-off. The contractor-issued certificate serves this purpose and is effectively required for compliance.
No. The waterproofing certificate should be issued by the licensed waterproofing contractor who actually performed the waterproofing work. A general builder can only issue a certificate if they hold a specific waterproofing licence from NSW Fair Trading.
If your original waterproofer is no longer operating, you can engage a building inspector or another licensed waterproofer to assess the existing waterproofing and provide a condition report. This may serve as a substitute for insurance or sale purposes.
While not legally required for sale, having waterproofing certificates adds value and confidence for buyers. Building inspectors commonly note the absence of waterproofing certificates in pre-purchase reports.
The certificate itself does not expire, but it documents a specific point in time. The associated warranty (typically 7-15 years) does have an expiry. The certificate remains useful as a historical record of the work performed.
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