Liquid Membranes Buyer's Guide — TradieCart
Browse Australia's widest range of liquid waterproofing membranes from leading brands including Ardex, Durotech, Crommelin, Enviro Systems, Tremco, Pasco, Laticrete, Demtech, Keratrade, and more. Whether you're waterproofing a residential bathroom, sealing a swimming pool, or coating an exposed balcony, you'll find the right membrane here.
Understanding Membrane Classifications
Liquid waterproofing membranes in Australia are tested and classified under AS/NZS 4858 for internal wet areas. The classification is based on elongation at break — how much the membrane can stretch before tearing:
- Class I — Low extensibility (10–59% elongation). Rigid membranes suited to stable substrates with minimal movement. Typically cementitious types.
- Class II — Medium extensibility (60–299% elongation). Moderate flexibility for general applications on stable concrete and cement sheet.
- Class III — High extensibility (300%+ elongation). Maximum crack-bridging ability. The most commonly specified class for under-tile waterproofing in wet areas.
A higher class means more flexibility, not automatically a "better" product — choose the class that matches your substrate and application. Class III is the default choice for most under-tile waterproofing. Separate standards apply: AS 3740 governs the design and installation of internal wet areas, while AS 4654 covers external above-ground waterproofing (balconies, podiums, rooftops) and requires UV and weather resistance testing.
Popular Products
| Product | Best For |
|---|---|
| Durotech P15 Diamond 15L | Cost-effective polyurethane-modified acrylic undertile membrane — the most viewed waterproofing product on TradieCart. Class III to AS 4858, 400%+ elongation. Rated for internal and external wet areas, balconies, decks, and planter boxes. Available in blue and grey. |
| Ardex WPM 155 Rapid Plus 20kg | Premium rapid-dry polyurethane-acrylic hybrid undertile membrane. Class III to AS/NZS 4858, tile-ready in 4 hours at 23°C. Covers approximately 17.5m² per 20kg unit over two coats. STB Tape system eliminates the need for bond breaker. Also available in 5.3kg for small jobs and repairs. |
| Gripset 38FC 15L | SBR fast-cure undertile membrane — the most widely stocked liquid membrane on TradieCart (6 vendors). Fibre reinforced, recoat in 1 hour, tile over in 4 hours. Covers 10m² per 15L pail over two coats. Internal and external wet areas including balconies and podiums. Also in 5L. |
| Keratrade WPM 19.5kg | Single-component water-based polyurethane membrane with 900% elongation — Class 3 to AS/NZS 4858 and AS 4654.2 compliant for both internal and external use. Eco-friendly with very low VOC emissions. A strong-performing option for wet areas, balconies, rooftops, and podiums. Not suited for immersed applications. |
| Crommelin Wetite 15L | Established SBR undertile membrane with a distinctive green colour that makes coverage inspection easy during application. Class III to AS 4858. No priming required on sound substrates. Also available as Wetite Rapid for faster cure times in green and grey. |
| Ardex WPM 002 40kg Kit | Two-part cementitious membrane rated for permanent water immersion — swimming pools, spas, and water tanks. Class III to AS 4858, fibre reinforced (no reinforcing mat needed). Tile-ready in 16–24 hours. Coverage: floors 16m² at 1.2 mm DFT, walls 24m² at 0.8 mm DFT. |
| Laticrete Hydro Ban 15L | Single-component self-curing liquid rubber polymer — no mixing and no fabric required in the field, coves, or corners. Class 3 to AS 4858 and AS 4654.1. Rated for immersed installations, swimming pools, steam rooms, and radiant heat systems. Coverage approximately 18m² per 15L pail. Anti-fracture protection up to 3 mm. |
| Pasco Aquaproof 115 UV Grey 15L | Moisture-curing elastomeric polyurethane membrane — UV stable, trafficable, and self-levelling with 450% elongation. Designed for exposed external applications: rooftops, podiums, balconies, walkways, and plant rooms where the membrane remains uncovered. |
| Tremco TREMproof 201/60R 18.9L | Single-component moisture-curing modified polyurethane for structural waterproofing. Tested to AS 4654.1, 85% solids content for reliable DFT control. Primer-less application on most concrete. Coverage 12.5m² per pail. Used on retaining walls, below-grade applications, tunnels, and planter boxes. |
Quick Recommendation Guide
- Standard residential bathroom on concrete → Durotech P15 Diamond for a cost-effective Class III option, Crommelin Wetite for a proven no-prime SBR, or Ardex WPM 155 Rapid Plus for premium performance with 4-hour tile-ready time
- Fast-cure — need to tile the same day → Gripset 38FC or Durotech 007FC — both SBR fast-cure formulations with 1-hour recoat and 4-hour tile-over time
- Swimming pool, spa, or water tank → Ardex WPM 002 two-part cementitious system for permanent water immersion. Laticrete Hydro Ban is also immersion-rated and requires no fabric or mixing
- Exposed external balcony or rooftop deck → Pasco Aquaproof 115 UV for a trafficable, self-levelling PU finish, or Enviro Clad for UV-resistant protection with a choice of 8 colours. Keratrade WPM also carries AS 4654.2 external compliance
- Below-grade or retaining wall → Tremco TREMproof 201/60R moisture-cure PU for structural applications, or cementitious systems like Gripset C-1P and Drizoro Maxseal Flex for negative hydrostatic pressure resistance
- Moisture barrier before floor coverings → Ardex WPM 300 epoxy or Laticrete Latapoxy Moisture Shield — two-part vapour barrier systems for sealing residual moisture in concrete slabs
- Commercial structural waterproofing → Tremco TREMproof 201/60R or Durotech Duroproof PPM — moisture-cure polyurethanes for podium decks, planter boxes, and demanding commercial specifications
Product Types
- Undertile Membranes (Acrylic & SBR) — The core of the category. Water-based acrylic, SBR rubber, or polyurethane-acrylic hybrid membranes applied under tiles in bathrooms, showers, laundries, and wet areas. Must comply with AS 4858. Low odour, water clean-up, and compatible with cement-based tile adhesives. Popular options: Durotech P15 Diamond, Ardex WPM 155 Rapid Plus, Gripset 38FC, Crommelin Wetite, Keratrade WPM/UTM, Laticrete Hydro Ban, Pasco Aquaproof 201PU, and Bostik Dampfix.
- Water-Based Polyurethane Membranes — Higher chemical resistance and flexibility than pure acrylic, with the same easy water clean-up. Suitable for internal wet areas and some external applications. Options: Enviro 700X, Bostik Dampfix Platinum, Sika Sikalastic WPU, Pasco Aquaproof 110, WSS Hydroflow UV, WMA UV Spec Ceramic, and Ardex WPM 157.
- Cementitious Membranes — Cement-based one-part or two-part systems for swimming pools, tanks, retaining walls, and below-grade applications. Can resist negative hydrostatic pressure. Lower cost per square metre for thick applications. Options: Ardex WPM 002, Mapei Mapelastic Smart, Gripset C-1P/2P, Crommelin Cemproof, Drizoro Maxseal Flex, Demtech Cureflex PCM17, Pasco Aquaproof 121/Crystalcoat, Sika Sikalastic 1K, and Durotech Duroflex 1K.
- UV-Stable & Exposed Membranes — Formulated to withstand direct sunlight and weather exposure without degradation. Used on balconies, rooftop decks, facades, and any surface where the membrane remains uncovered. Must comply with AS 4654 for external applications. Options: Enviro Clad (8 colours), Pasco Aquaproof 110/115/120 UV, Ardex WPM 310/330, Crommelin Membryl/Fibroseal, and Demtech Cureflex UVX4000.
- Trafficable Coatings — Tough, textured or non-slip membrane systems designed for pedestrian or light vehicle traffic on walkways, car park decks, and exposed podiums. Options: Dribond DeckGrip (7 colours), Enviro 950 TC/900, Enviro 250 NS, Kerakoll Aquastop Traffic, Ardex WPM 909, and Gripset LS.
- Moisture-Cure Polyurethane — Professional-grade single-component PU membranes that cure by reacting with atmospheric moisture. Superior chemical resistance for commercial and structural waterproofing. Not suitable for direct tiling — requires a bonding layer. Options: Tremco TREMproof 201/60R/250GC, Durotech Duroproof PPM/PU Black Eco, Sika Sikalastic 777, and Ardex WPM 812.
- Epoxy Moisture Barriers — Two-part epoxy systems forming an impermeable vapour barrier. Used to seal residual moisture in concrete slabs before installing moisture-sensitive floor coverings, or as immersion-grade pool membranes. Options: Ardex WPM 300 (grey and mojo black), Laticrete Latapoxy Moisture Shield, and RLA Moisture Seal.
- Bituminous Membranes — Modified bitumen products for below-grade, retaining wall, and concealed applications. Economical for large areas. Not suitable for tiling over. Options: Gripset 51/59, Tremco Hydroseal/Pabkote, Durotech BLW, Pasco Aquaproof 301 BL, V-Tech Vital Proof BX, and Crommelin Bitflex.
- Pond & Tank Sealers — Specialist coatings rated for permanent water immersion in ponds, water features, and tanks. Available in multiple colours. Options: Crommelin Pond Sealer (black, blue, clear, sandstone in 1L, 4L, 15L) and Durotech Duroflex Tank.
- Water Plugs & Injection Systems — Rapid-set compounds for stopping active water leaks and polyurethane injection resins for crack sealing in concrete structures. Options: Gripset C-Plug, Pasco Aquaplug, Enviro Plug, Durotech Duroflex Plug, Enviro Gel injection systems, and Tremco TREMcrete Aqua Dam.
Common Questions
How many coats do I need to apply? — Minimum two coats for virtually all liquid membranes. The second coat must be applied at 90 degrees to the first to ensure even coverage and eliminate pinholes. Some specifications require three coats for external or immersion applications. Always use a wet film thickness (WFT) gauge during application to verify coverage — the required dry film thickness (DFT) is typically 1.0 mm minimum for internal floors and 1.5 mm or more for external applications.
What is the difference between Class I, II, and III membranes? — The classification under AS/NZS 4858 is based on elongation at break. Class I (10–59%) is rigid, suited to stable substrates. Class II (60–299%) offers moderate flexibility. Class III (300%+) provides maximum crack-bridging and is the most commonly specified for under-tile waterproofing. Higher class means more flexible, not automatically better — choose the class that matches your substrate conditions.
Can I tile directly over every liquid membrane? — No. Acrylic, SBR rubber, and water-based polyurethane membranes can generally be tiled over with cement-based adhesives. However, moisture-cure polyurethane, bituminous, and some epoxy membranes have surfaces that are too smooth or chemically inert for tile adhesive to bond to. Always confirm tile adhesive compatibility with the membrane manufacturer before tiling.
What is the difference between internal and external membranes? — Internal wet area membranes are tested under AS 4858 for intermittent water exposure. External membranes must also comply with AS 4654 and withstand UV exposure, thermal cycling, and continuous weather. Using an internal-only membrane on an exposed balcony or deck will result in premature failure from UV degradation. Check the product data sheet — if it does not state external or AS 4654 compliance, it is for internal use only.
Can I use a standard wet area membrane in a swimming pool? — No. Standard undertile membranes are designed for intermittent water exposure only. Swimming pools, spas, and water tanks require immersion-rated products designed for continuous water contact under hydrostatic pressure. Products like Ardex WPM 002, Laticrete Hydro Ban, and Crommelin Pond Sealer are specifically rated for permanent immersion — always check the manufacturer's data sheet for pool suitability.
Do I always need to prime before applying a liquid membrane? — In most cases, yes. Primer consolidates surface dust, reduces porosity, and improves membrane adhesion. Use the primer recommended by the same manufacturer as your membrane — mixing brands can void the warranty. Some products are self-priming on clean, sound substrates (e.g., Crommelin Wetite requires no priming, and Tremco TREMproof 201/60R is primer-less on most concrete). Always prime when applying to fibre cement sheeting, highly porous surfaces, or existing tiles.
Brands We Stock
We carry liquid waterproofing membranes from Ardex, Durotech, Crommelin, Enviro Systems, Tremco, Pasco, Laticrete, Demtech, Keratrade, Gripset, Mapei, Bostik, Sika, Davco, Dribond, Drizoro, Kerakoll, RLA, WSS, Fastfix, SWP, V-Tech, Duracore, ATA, Megapoxy, SAS, WMA, Bluproof, and more — with fast delivery across Australia and same-day dispatch in Metro Melbourne.
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