Navigating the regulatory requirements for waterproofing in Perth does not have to be complicated. AS 3740 Explained for Homeowners explains the key standards, certifications, and legal obligations that apply to waterproofing work in Western Australia, helping you ensure that your project is compliant, warrantied, and protected against future problems.
Understanding AS 3740-2021
AS 3740-2021 is the primary Australian Standard governing waterproofing of domestic wet areas. It applies to all new construction and renovation work in bathrooms, showers, laundries, and other wet areas throughout Australia, including Western Australia. For more information, see our bathroom waterproofing guide guide. The standard specifies minimum membrane extent, performance requirements, testing protocols, and detailing requirements for different wet area configurations.
Key requirements under AS 3740 include full floor waterproofing in all wet areas, minimum 1800mm wall waterproofing in shower recesses, bond-breaker strips at all internal angles, waterproofing of all penetrations, and flood testing before tiling. The standard also specifies requirements for hob detailing, floor waste connections, and membrane compatibility with tile adhesives. Learn more through our AS 3740 compliance guide.
Compliance with AS 3740 is referenced by the National Construction Code and is therefore a legal requirement for all building work in Western Australia. The WA Building Commission enforces these requirements through the building permit and inspection process. Non-compliant waterproofing can result in building orders, insurance implications, and liability for resulting damage.
Choosing a Waterproofer: Key Questions to Ask
Selecting the right waterproofer is one of the most important decisions in any wet area project. The contractor’s skills, experience, and attention to detail directly determine whether your waterproofing will perform reliably for decades or fail within years. In Perth, where harsh climate conditions amplify the consequences of poor workmanship, choosing a qualified and experienced waterproofer is particularly important.
Key questions to ask a prospective waterproofer include: Are you registered with the WA Building Commission? What products do you use and why? Can you provide examples of similar projects you have completed? Do you issue waterproofing certificates? What warranty do you provide? Will you perform flood testing before tiling? Can you provide references from recent clients? A competent waterproofer will answer all of these questions confidently and provide documentation to support their claims. Learn more through our waterproofing certificate guide.
We connect Perth homeowners and builders with vetted, registered waterproofing contractors who specialise in the type of work your project requires. Our free matching service saves you the time and effort of researching and vetting contractors yourself, while ensuring that every contractor in our network meets our standards for registration, insurance, experience, and client satisfaction.
Waterproofing Certificates: What They Mean and Why You Need One
A waterproofing certificate is a formal document issued by the waterproofing contractor certifying that the waterproofing work has been carried out in accordance with AS 3740, the manufacturer’s installation instructions, and the National Construction Code. The certificate should specify the products used, areas waterproofed, membrane thickness achieved, and flood test results.
In Western Australia, a waterproofing certificate is required as part of the building certification process. Your building certifier or inspector will request the waterproofing certificate before approving subsequent construction stages such as tiling. For more information, see our wet area waterproofing requirements guide. Without a valid waterproofing certificate, you may not be able to obtain a certificate of occupancy or building completion for your renovation or new build.
When you receive a waterproofing certificate, verify that it includes the contractor’s licence details, the specific products and batch numbers used, confirmation of AS 3740 compliance, flood test results with dates, and the contractor’s signature and date. Keep this certificate in your property records — it is important documentation if you ever need to make a warranty claim, an insurance claim, or sell the property.
Get Expert Help with Your Waterproofing Project
Whether you are planning a new build, renovating an existing property, or dealing with a waterproofing issue that needs urgent attention, working with a licensed professional is the best way to ensure a lasting, compliant result. Perth has many experienced waterproofing contractors who understand the local conditions and can deliver the right solution for your specific needs.
Ready to get started? Use our free tool to find a licensed waterproofer in your area and request obligation-free quotes from vetted professionals. We connect you with licensed contractors who specialise in the type of waterproofing your project requires, so you can compare options and make an informed decision with confidence.