Fast, legitimate waterproofing compliance certificates for bathrooms, balconies and builds. Issued only after inspection and flood testing by our licensed NSW technicians.
AS 3740:2021, Waterproofing of Domestic Wet Areas, is the Australian Standard that governs how waterproofing must be installed in the wet areas of residential buildings across Australia. It specifies the minimum requirements for membrane types, application thicknesses, wet area geometry, drainage, upstand heights, and junction treatments for areas including bathrooms, shower enclosures, laundries, and any other room subject to regular water use.
AS 3740 is not a best-practice guideline. It is a mandatory technical requirement referenced by the National Construction Code and the Building Code of Australia. In NSW, compliance with AS 3740 is a legal obligation for any waterproofing work carried out on residential buildings. Under the Design and Building Practitioners Act 2020, licensed waterproofing contractors must formally declare that their work complies with the relevant Australian Standard.
Key requirements under AS 3740 include minimum membrane thickness and coverage at all wet area surfaces, specific upstand heights of a minimum 150mm above floor level on all walls adjacent to shower recesses and baths, full waterproofing coverage of the shower base including a coved junction between floor and wall, flood testing before tiling with a 25mm water depth held for 24 hours, waterproofing of hob or shower threshold junctions, and full documentation by the installing contractor.
A waterproofing compliance certificate is a formal written document issued by the licensed waterproofing contractor who carried out the work. It certifies that the waterproofing has been installed in accordance with the applicable Australian Standard: AS 3740 for domestic wet areas, or AS 4654 for external wet areas including balconies and terraces.
The certificate must include the contractor’s name, company name, and NSW licence number, the address of the property, the scope of waterproofing work completed, the Australian Standard the work was completed to, the membrane product used and its application rate, the date of flood test completion and the test result, and the date the certificate was issued.
A legitimate waterproofing certificate can only be issued by the licensed contractor who completed the waterproofing work, or by a licensed contractor who has physically inspected the work and conducted a flood test. No certifier can issue a compliance certificate for work they did not carry out or inspect. Any certificate issued without a flood test or physical inspection is not a valid AS 3740 compliance certificate and may expose the property owner to liability.
Econyc issues compliance certificates only for work we have completed or fully inspected. We do not issue retrospective certificates for work by other contractors without inspection and testing.
There are multiple circumstances in NSW where a waterproofing compliance certificate is required or strongly advisable. After any bathroom or wet area renovation, tiles cannot and should not be laid over uncertified waterproofing. Any tiling contractor working to the National Construction Code should refuse to tile over waterproofing that has not been inspected and certified.
When selling a property, buyers and conveyancers increasingly request waterproofing compliance certificates as part of pre-purchase due diligence, particularly in apartments and recently renovated properties. An absence of a certificate can raise concern, lower offers, or delay settlement.
For strata approval, virtually all strata managers and owners corporations in NSW require a waterproofing compliance certificate before approving any wet area repair or renovation. For building certification, council-issued development consent conditions or private certifier inspections may specifically require waterproofing certificates as a hold point before the next construction stage proceeds. For insurance purposes, in the event of water damage claims, insurers may require proof that waterproofing was installed compliantly. After remedial waterproofing, a certificate confirms the repair meets the current standard.
Econyc’s waterproofing certification process is thorough and non-negotiable. We do not take shortcuts, issue desk certificates, or certify work we have not personally inspected and tested.
Where Econyc carries out the waterproofing work we are certifying, we use only top-tier products from Normet, Sika, and Tremco. These manufacturers carry full Australian technical data, independent testing records, and manufacturer warranties.
For domestic wet area waterproofing to AS 3740, the primary products we apply and certify include Sika TanDrain (a flexible liquid waterproofing membrane with high elongation suitable for wet areas subject to minor structural movement), Sika TiteDeck (a reinforced waterproofing system for shower bases and wet area floors), Tremco TREMproof 60 (a one-component polyurethane membrane for internal wet areas and balconies), and Tremco Dymonic (a polyurethane sealant for movement joints, screen penetrations, and expansion joints within wet areas).
Using premium specified products matters for warranty validity. All manufacturer warranties from Sika and Tremco are conditional on the product being applied by a trained applicator in accordance with the technical data sheet. Econyc’s technicians maintain current product training and applicator status with all primary product suppliers.
When Econyc carries out the waterproofing that is the subject of the certificate, our standard workmanship warranties apply: a 5-year workmanship warranty for bathroom and shower waterproofing, and a 10-year workmanship warranty for balcony and external wet area waterproofing.
The warranty is documented in writing alongside the compliance certificate and is transferable on property sale. It covers defects in our application of the waterproofing system. It does not cover damage caused by subsequent structural movement, modifications by others, or conditions outside the waterproofing scope.
Where Econyc is issuing a certificate for waterproofing carried out by another contractor, we cannot provide a workmanship warranty on the underlying work. We certify only that the work passes the inspection and flood test at the time of our visit.
Can I get a waterproofing certificate for an old bathroom?
Yes, but only if the waterproofing passes inspection and flood testing. For older bathrooms where the original waterproofing may not comply with AS 3740:2021, the inspection may reveal deficiencies. In that case we advise on remediation required to bring the bathroom to a certifiable standard, then issue the certificate once that work is complete. We do not issue certificates for bathrooms that do not pass inspection.
How much does a waterproofing compliance certificate cost?
If Econyc carries out the waterproofing, the certificate is included in the job price at no additional charge. For inspection-only certificates where we are assessing existing waterproofing, pricing depends on the number of wet areas and the location. Contact us for a fixed-price inspection quote.
Can a tiler issue a waterproofing certificate?
Only a licensed waterproofing contractor can issue a waterproofing compliance certificate in NSW. A tiler who is not separately licensed as a waterproofer cannot legally certify waterproofing work. In NSW, the waterproofing licence under the Home Building Act is separate from the tiling licence.
My builder says I do not need a waterproofing certificate for a renovation. Is that right?
Under the NCC and AS 3740, waterproofing of wet areas must be inspected before tiling in new builds and major renovations. We strongly recommend insisting on a certificate for any waterproofing work, particularly if you plan to sell the property in future.
How long does the certification inspection take?
For a standard 2-bathroom home, the inspection visit takes approximately 1.5 to 2 hours. If flood testing is required, water is set and we return 24 hours later to record the result, adding a second brief visit. The certificate is issued within 24 to 48 hours of the completed inspection.
Contact Econyc today for a free site inspection and fixed-price quote. Licensed, insured, and fully compliant with Australian waterproofing standards.