Of all the stage inspections VG Inspect conducts across Brisbane and SEQ, the waterproofing inspection has the clearest and most direct financial benefit. Here's why.
The Problem with Waterproofing
Waterproofing membranes in shower enclosures, bathrooms, laundry areas and balconies are installed before tiling. Once tiles are laid, the membrane is permanently hidden. Any defect in the membrane — insufficient height, incomplete coverage, unsealed junctions, damage from trades — is also hidden.
A non-compliant waterproofing membrane doesn't fail immediately. It fails over months and years as water penetrates through grout lines, through unsealed junctions and through areas where the membrane doesn't meet the required standards. By the time the failure is visible — water staining, mould, delaminating tiles, damage to substrate or structure — the remediation required is extensive.
What Non-Compliant Waterproofing Actually Costs
Remediating a failed shower waterproofing system requires: removal of all tiles and tile adhesive from the floor and walls of the shower enclosure, removal of the failed membrane, assessment of substrate damage, replacement of the substrate where necessary, application of a new compliant membrane system, curing time, application of new tile adhesive and tiling, grouting and silicone junctions.
The cost of this process for a single shower enclosure in a Brisbane home ranges from $8,000 to $25,000 depending on the extent of substrate damage, the tile specification and the trades involved. For a bathroom with a separate bath and a floor waste, add the bath waterproofing remediation to that figure.
The cost of a waterproofing inspection conducted before tiles are laid: $550.
What the Standards Require
Under NCC Volume 2 Part 3.8.1.1 and AS3740, wet area waterproofing in shower enclosures must meet specific requirements that are often not met in practice.
The membrane must be applied to a minimum height of 1800mm on all shower walls. In a standard 2400mm ceiling height shower, that's 75% of the wall height. We regularly find membranes that have been applied to 900mm or 1200mm — half or two-thirds of the required height — because the waterproofing contractor assumed tiles would provide waterproofing above that point. They don't.
The membrane must be continuous across all floor and wall junctions — the coved junction at the base of the shower wall is a critical detail that is frequently inadequate. This junction is the highest-risk point for water penetration because it is the point where floor movement and wall movement create differential stress on the membrane.
All penetrations through the membrane — floor wastes, shower hob pipes, wall penetrations — must be sealed with an appropriate collar or flashing that maintains membrane continuity. Unsealed penetrations are a direct water ingress path.
Ready to book your inspection? A VG Inspect QBCC-licensed inspector attends every job.
Book an InspectionWhat We Look For
During a VG Inspect waterproofing inspection we assess:
Membrane height. We measure from the finished floor height to the top of the applied membrane on all shower walls. 1800mm is the minimum — we document the actual height found.
Junction treatment. Floor to wall junctions must show a continuous, properly formed cove. We look for bridging, voids and areas where the membrane doesn't make full contact with the substrate.
Penetration sealing. Every pipe penetration, waste fitting and structural penetration through the membrane is assessed for correct collar or flashing installation.
Coverage continuity. Gaps, holidays (areas missed during application) and areas where the membrane has been damaged by subsequent trades are identified.
Balcony and alfresco waterproofing. External waterproofed areas must slope to drainage at a minimum of 1:100. Falls less than this allow water to pond on the membrane surface, accelerating membrane degradation.
The Timing Problem
The window for a waterproofing inspection is narrow. Membranes must cure before tiling can begin — typically 24 to 48 hours for most membrane systems. Once the tiling contractor arrives, the window closes.
Builders don't always notify clients when waterproofing is complete. We recommend asking your builder or site supervisor to notify you specifically when wet area waterproofing is done, so you can book immediately.
What If Non-Compliant Waterproofing Is Found?
Non-compliant waterproofing found before tiling is straightforward to rectify. The membrane contractor returns, the deficient areas are addressed and you book a follow-up inspection to confirm compliance before tiling proceeds.
The cost of rectification at this stage is minimal — typically a trade return and additional membrane product. It is measured in hundreds of dollars, not thousands.
The same defect found after handover is a warranty dispute. Even if the defect is clearly covered by the QBCC Home Warranty scheme, the process of making a warranty claim, having it assessed, getting the builder to return and complete the rectification work — while you're living in the home — is protracted and disruptive.
Book your waterproofing inspection before tiles go on. It is the highest-value inspection window in your entire build.
Ready to book your inspection? A VG Inspect QBCC-licensed inspector attends every job.
Book an Inspection