Most wet area failures come down to a handful of details: a junction that wasn't reinforced, a floor waste that wasn't sealed properly, or a membrane that was tiled over before it cured. This checklist walks through the steps waterproofers and tilers work through on a typical bathroom, laundry or shower, and the products we stock for each.
Important: this is a practical guide, not a substitute for the standard. AS 3740 sets the requirements for waterproofing domestic wet areas, and your state may have additional licensing and certification rules. Always work to the current version of the standard, the membrane manufacturer's system requirements, and your local regulations.
1. Substrate preparation
- Substrate is sound, clean, and free of dust, oil, curing compounds and loose material.
- Falls to the waste are formed in the screed, not built up in the tile bed.
- Substrate moisture is within the membrane manufacturer's limits. On damp or moisture-affected slabs, consider an epoxy moisture barrier such as Gripset E60 or Laticrete Latapoxy Moisture Shield.
2. Prime
- Use the primer specified for your membrane system and substrate. Porous substrates and non-porous or hard-to-bond surfaces usually need different primers.
- Allow the primer to dry fully before the membrane goes on.
- Browse primers and bonding agents, including Gripset P39 and fast-drying Xpress Primer H2O Plus.
3. Junctions, corners and movement joints
- Treat floor-to-wall and wall-to-wall junctions with the bond breaker or reinforcement your membrane system requires, so the membrane can accommodate movement.
- Use pre-formed corners at internal corners, such as Elastoproof CN90 corners.
- Embed reinforcing band or tape into the membrane at junctions and control joints. See joint bands and sealing tapes.
4. Penetrations and floor wastes
- Every floor waste has a puddle flange or waterproofing collar so the membrane seals to the drain body.
- Pipe penetrations through walls and floors are sealed with collars or tape compatible with the membrane.
- See our floor drains, puddle flanges and PVC collars and Elastoproof CL-Blind collars in the waterproofing range.
5. Apply the membrane
- Apply the number of coats and the dry film thickness the manufacturer specifies. Thin spots are a common cause of failure.
- Extend the membrane to the heights and areas required by the standard for that part of the wet area.
- Allow each coat to dry as specified before the next.
- Choose your system from liquid and sheet membranes, including Gripset, Laticrete and Mapei.
6. Cure, inspect and document
- Let the membrane cure fully before tiling. Don't let other trades walk on or damage it.
- Inspect junctions, penetrations and edges before tiles go down.
- Issue any certificate or documentation required in your state.
7. Tiling over the membrane
- Use an adhesive compatible with the membrane. Check the membrane data sheet.
- Seal perimeter and movement joints with a flexible sealant rather than grout. See wet area silicones.
Need help matching a primer, membrane and accessories into one compatible system? Get in touch. Trade pricing and Australia-wide delivery.