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Prepare a sound, clean substrate; form drainage falls; prime if the system requires it; reinforce corners, joints, and penetrations; then apply the specified membrane coats at the correct thickness before flood testing and tiling.
This guide is written for South Africa, Australia, New Zealand. Always check local codes, product specifications, licences, and site conditions.
Resolve the complete wet-area system first
Waterproofing cannot be designed one product at a time. The substrate, falls, drain, threshold, penetrations, membrane, adhesive and tile finish must form one compatible build-up.
- Approved drawings or local requirements showing waterproof and water-resistant extents.
- The drain body, flange, grate height and method of connecting the membrane.
- Substrate and fixing details, including joints, recesses, corners and movement locations.
- One manufacturer-approved primer, bond breaker, membrane, reinforcement and sealant system.
- Required dry-film thickness, number of coats, coverage rate and curing conditions.
Critical shower details to approve before coating
Most failures begin at transitions rather than in the broad middle of a wall. Review each detail while it is still visible and accessible.
| Detail | What must be resolved | Typical failure |
|---|---|---|
| Floor waste | Compatible flange, membrane termination, falls and finished grate height | Water bypasses or ponds around an unbonded drain connection |
| Corners and movement joints | Specified bond breaker or reinforcing detail with movement capacity | Rigid membrane tears where planes move differently |
| Tap and shower penetrations | Sleeves, proprietary seals or compatible flexible sealing | Water follows pipework into the wall cavity |
| Doorway or hobless entry | Waterstop, membrane return, finished falls and splash control | Water escapes beneath finishes into the adjoining room |
Deeper guidance
Substrate readiness matters more than coating speed
The base must be sound, correctly fixed, sufficiently flat, clean and within the membrane maker’s moisture limits. Sheet joints, fasteners and changes of material need the specified treatment. Waterproofing over movement, contamination or an uncured screed creates a concealed weakness that tiles cannot reinforce.
Measure the membrane instead of trusting appearance
Wet colour is not evidence of dry-film thickness. Record the product batch, surface area, calculated consumption, coat times and environmental conditions. Use the manufacturer’s wet-film gauge or coverage method where specified, and inspect pinholes, corners and penetrations under good light before tiling hides them.
Protect the membrane after installation
Respect cure time and prevent other trades from puncturing, contaminating or walking over the system. Use compatible tile adhesive and preserve movement joints through the finish. Where local rules require a licensed waterproofer, inspection, certificate or flood test, arrange it before tile installation and retain the record with the home file.
Step by step
Confirm the substrate
The base must be rigid, clean, dry enough for the selected system, and free from dust, oil, curing compounds, and loose material.
Create positive drainage
Form a consistent fall toward the waste so water cannot pond. Correct geometry before applying the membrane.
Detail changes of plane
Use compatible bond breakers, tapes, or reinforcement at corners, joints, wastes, and pipe penetrations as the manufacturer specifies.
Apply and verify
Apply the full system to its stated coverage and dry-film thickness. Allow curing, inspect for pinholes, then perform the required water test.
Expert tips
- Use one compatible system from primer through membrane.
- Photograph concealed waterproofing before tiling.
- Local codes may require licensed or certified waterproofing work.
Common questions
Do tiles and grout make a shower waterproof?+
No. Tile and grout are finish layers; the membrane behind or beneath them is the primary water-control layer.
How many coats of waterproofing are needed?+
Follow the selected system specification. Many liquid systems use two or more coats, but thickness and coverage matter more than a generic coat count.
Can I tile the same day?+
Usually not. The membrane must cure fully under the actual temperature and humidity conditions before it is covered.
Sources & further reading
We link to official building-code, government and public-health material where a technical or safety claim needs authoritative context. Local rules and adopted code editions can change.
- South African GovernmentNational Building Regulations and Building Standards Amendment ActSouth African building-control and approval framework.↗
- Australian Building Codes BoardWaterproofing in housesNational Construction Code overview for domestic wet-area waterproofing.↗
- New Zealand Building PerformanceBuilding Code: E MoistureOfficial requirements for surface water, external moisture and wet areas.↗
Stop if the work involves structural uncertainty, hazardous materials, heights, live services, gas, serious water damage, or regulated work. Local rules differ—use an appropriately licensed professional where required.