Repair Systems — 01
Cementitious flexible waterproofing membranes
Technical product reference for two-component polymer-modified cementitious waterproofing membranes. Covers product classification, AS 4858 class ratings, system selection, application requirements, and brand comparisons for Australian Class 2 strata building applications.
What are cementitious flexible waterproofing membranes?
Cementitious flexible waterproofing membranes are two-component, polymer-modified, cement-based systems applied by brush, roller, or trowel to form a flexible, bonded waterproof layer. They consist of a powder component (cement-based) and a liquid component (acrylic or polymer dispersion) that are mixed on site immediately before application. Once cured, the membrane forms a hard, flexible, cement-bonded film that is directly compatible with cementitious tile adhesives, screed, and grout systems without requiring a bond breaker or primer in most applications.
This category is distinct from polyurethane and hybrid liquid membranes. Cementitious flexible membranes are cement-based — not polyurethane. They generally have lower elongation than pure polyurethane systems and are not appropriate as a substitute for a polyurethane or AS 4858 Class III membrane where high elongation, active crack bridging, or significant substrate movement is the primary concern. However, for standard under-tile balcony waterproofing on stable concrete substrates, two-part cementitious systems are a well-established and widely used specification in Australian Class 2 strata remediation.
Product selection must consider the AS 4858 class rating, elongation performance, whether reinforcing fabric or mesh is required at junctions, primer requirements, minimum DFT, tile-over time, compatibility with the tile adhesive system above, and whether the membrane is confirmed for external above-ground use under AS 4654 in addition to AS 4858.
Product Reference
6 products — 5 brands — two-component cementitious flexible membranes only — scroll to view all
ARDEX WPM 002
Two-component cementitious flexible membrane — Class III AS 4858
Two-component microfibre-reinforced cementitious membrane — under-tile, screed, and paver systems — internal and external — no separate reinforcement mat at field areas
System Description
ARDEX WPM 002 is ARDEX Australia's primary two-component cementitious flexible waterproofing membrane for under-tile balcony, terrace, and wet area applications. It is a modified cementitious system — not a polyurethane — and is formulated specifically for direct compatibility with ARDEX polymer-modified tile adhesive systems without requiring a bond breaker or intermediate layer. The product has been uniquely formulated with synthetic microfibres integrated into the mix, which increases tensile strength and eliminates the need for a separate reinforcing mat in field areas. At corners, coves, drain surrounds, and penetrations, ARDEX still recommends reinforcing tape or fabric embedded in the first coat — confirm current detailing requirements with ARDEX technical. Apply in two coats to achieve the specified minimum DFT of 1.2mm on floors and 1.0mm on walls. Tile over is typically 16–24 hours at 23°C/50% RH — in non-critical areas as little as 4 hours under optimal conditions. WPM 002 complies with AS 4858 as a Class III wet area membrane (confirmed by CSIRO Report 3879) and with AS 4654 for external above-ground applications. Note: ARDEX WPM 002 is the Australian product — do not use US ARDEX 8+9 TDS data for Australian projects.
Technical Properties
- Two-component modified cementitious membrane — powder + liquid components mixed on site
- Synthetic microfibre reinforcement integral to the mix — no separate reinforcing mat required at field areas
- Class III per AS 4858 — confirmed by CSIRO Report 3879
- AS 4654 compliant for external above-ground applications — low VOC — solvent free — will not re-emulsify once cured
- Minimum DFT: 1.2mm floors (two coats), 1.0mm walls (two coats) — tile-over 16–24 hours at 23°C, as little as 4 hours non-critical
- Suitable substrates: concrete (28 days minimum cure), masonry, render, fibre cement compressed sheet, plywood, wet-wall linings
- Compatible with ARDEX polymer-modified tile adhesive systems — also suitable under polymer-modified screed and paver/decking systems
Limitations
- Not a polyurethane membrane — do not substitute for a PU Class III system where high elongation or active crack bridging is required
- Reinforcing tape or fabric still required at all coves, junctions, drain surrounds, and penetrations — microfibre integral reinforcement does not eliminate junction detailing requirements
- Minimum two coats required to achieve specified DFT — single coat is not sufficient
- Not suitable for direct trafficable exposure — must be covered with tiles, screed, or pavers
- Do not apply to wet or standing-water substrates — substrate must be sound, clean, and damp-dry before application
- Confirm current product specification with ARDEX Australia before specifying — do not use US ARDEX 8+9 TDS for Australian projects
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Mapei Mapelastic Smart
Two-component cementitious flexible membrane — Class II — crack-bridging >2mm
Two-component high-flexibility cementitious mortar — crack-bridging greater than 2mm — Class II — balconies, terraces, bathrooms, and pools — UV resistant
System Description
Mapei Mapelastic Smart is Mapei Australia's primary high-flexibility two-component cementitious waterproofing membrane for balconies, terraces, bathrooms, showers, and swimming pools. At 2mm thickness, it achieves a crack-bridging capacity greater than 2mm, which distinguishes it from lower-elongation cementitious membranes and makes it appropriate for use on substrates with minor movement. The product is classified as Class II per AS/NZS 4858 with 170% elongation at failure — it is not Class III. For projects requiring Class III elongation performance, a polyurethane or hybrid membrane must be specified instead. However, for standard balcony under-tile waterproofing on concrete substrates, Class II cementitious performance with more than 2mm crack bridging covers the majority of remediation scenarios on stable Class 2 strata buildings. Apply by brush, roller, trowel, or spray at a minimum 2mm thickness. Reinforcing fabric — Mapetex Sel (non-woven polypropylene) or Mapenet 150 (fibreglass mesh) — must be embedded in the first coat at all coves, corners, junctions, drain surrounds, and penetrations. UV resistant — suitable for temporary UV exposure during construction before tiling. Approved for potable water contact (AS/NZS 4020:2018). Can be applied over existing tiles that are clean and well bonded.
Technical Properties
- Two-component high-flexibility cementitious mortar — brush, roller, trowel, or spray-rendering machine application
- Crack-bridging capacity greater than 2mm at 2mm DFT — Class II per AS/NZS 4858 — 170% elongation at failure
- UV resistant — suitable for temporary exposure before tiling — approved for potable water contact (AS/NZS 4020:2018)
- CE certified — EN 1504-2 and EN 14891 — can be applied over existing tiles (clean and well bonded)
- Pot life: 60 minutes after mixing at +20°C — waiting time between coats: 4–5 hours — tile-over: minimum 5 days after final coat
- Application temperature range: +5°C to +35°C — consumption approximately 1.6 kg/m² per mm by roller or brush
- Reinforcement: Mapetex Sel or Mapenet 150 at all junctions — mandatory — not optional
Limitations
- Class II only — not Class III — do not substitute for a PU Class III membrane where Class III elongation is specified or required
- Tile-over time is 5 days minimum — programme must account for this — not suitable where a fast tile-over programme is required
- Reinforcing fabric mandatory at all coves, corners, junctions, and drain surrounds — Mapetex Sel or Mapenet 150 must be embedded in first coat
- Pot life 60 minutes — plan batch sizes carefully to avoid waste — particularly important in hot weather
- Do not apply in temperatures below +5°C or above +35°C — protect from rain and water spillage for 24 hours after laying
- Confirm current product specification with Mapei Australia before specifying
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Mapei Mapelastic Foundation
Two-component cementitious flexible membrane — thixotropic — positive and negative pressure
Two-component flexible cementitious mortar — positive and negative hydraulic pressure — thixotropic — concrete and masonry structures, pools, tanks, retaining walls, and below-grade
System Description
Mapei Mapelastic Foundation is Mapei's two-component flexible cementitious waterproofing mortar for concrete and masonry structures subject to both positive and negative hydraulic pressure. Unlike Mapelastic Smart — which is positioned primarily for above-ground balcony and wet area waterproofing — Mapelastic Foundation is formulated with a thixotropic consistency suited to below-grade structures, retaining walls, swimming pools, water tanks, basement walls, and hydraulic structures. Its thixotropic consistency makes it well suited to vertical and overhead concrete surfaces where a fluid-consistency product would sag or run. Minimum applicable thickness is 2mm applied in two coats. The mixing ratio is 2.2 parts powder to 1 part liquid. Pot life is approximately 1 hour at +20°C. Applied by roller or spray. On balcony and terrace applications, Mapelastic Foundation is most relevant where the balcony structure is subject to significant moisture loading from below or where a negative-pressure waterproofing system is required — for example, where water ingress through the slab is coming from above and the membrane must resist hydrostatic lift from beneath. For standard positive-side under-tile balcony waterproofing on a dry concrete substrate, Mapelastic Smart is the more appropriate Mapei product. Classified to EN 1504-2 and EN 14891 — EMICODE EC1R Plus certified.
Technical Properties
- Two-component flexible cementitious mortar — thixotropic consistency — suitable for vertical and overhead surfaces without sagging
- Designed for positive and negative hydraulic pressure applications — concrete and masonry under hydraulic loading
- Minimum 2mm DFT applied in two coats — mixing ratio: 2.2 parts powder (comp. A) : 1 part liquid (comp. B)
- Pot life: approximately 1 hour at +20°C — application temperature: +5°C to +40°C
- Applied by roller or spray — consumption by roller: 1.65 kg/m² per mm — by spray: 2.2 kg/m² per mm
- Classified to EN 1504-2 (coating C, principles PI, MC, IR) and EN 14891 — EMICODE EC1R Plus — very low VOC emission
- Suitable substrates: concrete and masonry under positive or negative hydraulic pressure — confirm AS compliance with Mapei Australia
Limitations
- Not the primary Mapei product for standard above-ground balcony under-tile waterproofing — for standard balcony and wet area use, specify Mapelastic Smart instead
- Confirm AS 4858 and AS 4654 compliance status for Australian balcony applications with Mapei Australia technical — the product is classified to EN standards, not confirmed AS-classified in publicly available Australian TDS
- Pot life 1 hour — plan batch sizes to avoid waste
- Not a direct substitute for Mapelastic Smart — different consistency, mixing ratio, and primary application scope
- Confirm reinforcing fabric requirements and AS compliance status with Mapei Australia technical before specifying for balcony use
- Confirm current product specification with Mapei Australia before specifying
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Davco K11 Flex
Two-part acrylic-modified cementitious waterproofing system
Two-part acrylic-modified cementitious waterproofing system — bonds to damp substrates — under-tile balcony, terrace, basement, and wet area use — nationally stocked
System Description
Davco K11 Flex is a two-part acrylic-modified cementitious waterproofing system from Davco (Laticrete Australia) — one of the most widely distributed cementitious membrane systems in Australian trade supply, available nationally through Bunnings and trade distributors. It is a practical choice for standard under-tile balcony and wet area waterproofing, particularly in conditions where the substrate surface cannot be fully dried before application. K11 Flex is specifically formulated to be applied to dampened or pre-wetted surfaces — a practical advantage on balcony remediation projects in humid conditions or where the concrete substrate retains residual moisture. The two components react chemically after mixing to form a hard, elastic film that bonds tenaciously to most concrete and masonry substrates. Tiles, renders, and screeds can be fixed directly over the cured membrane using Davco tile adhesives. K11 Flex is suited to internal wet areas, external balconies and terraces under tiles, and basement walls in both positive and negative water pressure conditions. In external areas, application is compatible with variable weather conditions — a practical advantage for exposed strata balcony work. Confirm the current product TDS and AS compliance status directly with Davco / Laticrete Australia before specifying.
Technical Properties
- Two-part acrylic-modified cementitious system — powder + liquid components mixed on site
- Designed for application to dampened or pre-wetted surfaces — substrate does not need to be fully dried before application
- Hard elastic film after cure — bonds tenaciously to concrete and masonry substrates
- Suitable for positive and negative water pressure applications — basements, retaining walls, and above-ground wet areas
- Direct compatibility with Davco tile adhesive systems after cure — tiles, renders, and screed can be fixed directly over cured membrane
- Internal and external use — balconies, terraces, bathrooms, basements
- Widely available nationally — Bunnings in-store and through trade distributors
Limitations
- Confirm current AS 4858 class rating (Class II or III) and AS 4654 compliance with Davco / Laticrete Australia — confirm from current TDS, not from third-party sources
- Reinforcing fabric requirement at junctions and coves must be confirmed with Davco technical — do not assume the mix alone is sufficient at movement-critical details
- Not a polyurethane membrane — do not substitute where Class III elongation or active crack bridging is required
- Not a trafficable exposed membrane — must be covered with tiles, screed, or pavers
- Confirm tile adhesive compatibility — use Davco-approved adhesive systems over the cured membrane
- Confirm current product name, formulation, and specification with Davco / Laticrete Australia before specifying — product range subject to periodic revision
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Fosroc Nitoproof 410
Two-component cementitious flexible membrane — Class III (wet areas) — AS 4858
Two-component fast-drying cementitious flexible waterproofing membrane — Class III AS 4858 wet areas — under-tile balcony, terrace, and podium — trafficable when overcoated with Nitoproof Top Coat UV
System Description
Fosroc Nitoproof 410 (formerly marketed as Emer-Proof Aqua Barrier Quick Dry) is a two-component, polymer-modified, cementitious flexible waterproofing membrane distributed in Australia through Parchem Construction Supplies (DuluxGroup). It is classified as a Class III membrane for wet areas under AS 4858 and is designed for under-tile waterproofing of balconies, terraces, podium slabs, and internal wet areas. A key feature is its fast-drying formulation, which reduces waiting time between coat applications and before tile adhesive can be applied — confirm current tile-over time with the active TDS from Parchem or the Fosroc Australia website before programming the works. When overcoated with the companion Nitoproof Top Coat UV product, Nitoproof 410 can be specified as a trafficable exposed membrane system for light foot traffic — this is an important product feature for podium and terrace applications where exposed trafficable waterproofing is required. Apply by brush or roller. Reinforcing tape or fabric is required at all coves, junctions, drain surrounds, and penetrations — confirm detailing requirements with Fosroc / Parchem technical. Distributed primarily through Parchem Construction Supplies branches nationally.
Technical Properties
- Two-component polymer-modified cementitious membrane — powder + liquid components mixed on site
- Class III classification for wet areas per AS 4858 — confirm against current TDS and Parchem technical for project specification
- Fast-drying formulation — reduced waiting time between coats and before tile application — confirm current tile-over time with TDS
- Trafficable when overcoated with Fosroc Nitoproof Top Coat UV — provides exposed trafficable waterproofing for balconies and podiums
- Suitable for under-tile balcony, terrace, and podium slab waterproofing — internal and external applications
- Apply by brush or roller — reinforcing tape or fabric required at all junctions, coves, drain surrounds, and penetrations
- Distributed nationally through Parchem Construction Supplies (DuluxGroup) branches
Limitations
- Confirm current AS 4858 class rating, elongation, and DFT requirements from the current Fosroc / Parchem TDS — product was formerly marketed as Emer-Proof Aqua Barrier Quick Dry — confirm current product name before ordering
- Reinforcing tape or fabric required at all movement-critical details — do not apply as a single-layer system at junctions without embedded reinforcement
- Not a polyurethane membrane — do not substitute for a PU Class III membrane where high elongation or active crack bridging is required
- Substrate must be sound, clean, and dry — not suitable for application to wet or standing-water substrates
- Trafficable exposed system requires Nitoproof Top Coat UV overcoat — do not leave membrane uncoated in exposed trafficable applications
- Confirm current product specification and availability with Parchem Construction Supplies before specifying
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Sika Sikalastic-1K
One-component cementitious waterproofing mortar — AS 4654.1 — EN 14891
One-component fibre-reinforced cementitious waterproofing mortar — crack-bridging — pools, tanks, basins, and external above-ground concrete — AS 4654.1 compliant — water-activated, no polymer liquid component
System Description
Sika Sikalastic-1K is a one-component, fibre-reinforced cementitious waterproofing mortar from Sika Australia. It is important to clearly distinguish this product from two-component cementitious membranes listed on this page — Sikalastic-1K is activated by adding water only, with no polymer liquid component mixed in the field. It is not a two-component polymer dispersion system. Sikalastic-1K is formulated for concrete protection and waterproofing of pools, tanks, basins, retaining walls, and external above-ground concrete structures. It complies with AS 4654.1 for external above-ground waterproofing and is classified to EN 14891. Integral fibre reinforcement provides crack-bridging capability — confirm the crack-bridging rating and elongation performance from the current Sika Australia TDS before specifying for balcony or terrace applications where movement is expected. The product is also used as a cementitious protective coating for concrete structures subject to water immersion. Note: Sika Davco K11 Flex (also listed on this page) is Sika / Davco's two-component cementitious membrane system commonly used for under-tile balcony waterproofing. Sikalastic-1K is a different and separate product line with a different primary application scope. Do not substitute one for the other without confirming performance requirements with Sika Australia technical.
Technical Properties
- One-component cementitious waterproofing mortar — activated by adding water only — no polymer liquid component required
- Integral fibre reinforcement — provides crack-bridging capability — confirm crack-bridging rating and elongation from current TDS
- AS 4654.1 compliant for external above-ground waterproofing — EN 14891 classified
- Suitable for pools, tanks, basins, retaining walls, and external concrete surfaces subject to water immersion
- Applied by brush, roller, or spray — confirm application method, number of coats, and minimum DFT from current TDS
- Confirm potable water approval and AS/NZS 4020 compliance status with Sika Australia for drinking water contact applications
- Confirm AS 4858 wet area classification status with Sika Australia before specifying for balcony under-tile applications
Limitations
- This is a ONE-COMPONENT system — activated by water only — it is not a two-component polymer-modified membrane and must not be treated as equivalent to ARDEX WPM 002, Mapelastic Smart, or K11 Flex
- Confirm AS 4858 wet area class rating with Sika Australia — the product is classified to EN 14891 and AS 4654.1 but confirm AS 4858 status before specifying for under-tile wet area applications
- Not a direct substitute for Sika Davco K11 Flex — different product category, different mixing method, different primary application scope
- Confirm crack-bridging rating and elongation from current TDS before specifying for substrates with expected movement
- Confirm tile-over time and tile adhesive compatibility with Sika Australia before specifying for under-tile use
- Confirm current product name, formulation, and TDS with Sika Australia before specifying — Sika product ranges are subject to periodic revision
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Comparison
Side-by-side comparison of two-component cementitious flexible membrane systems. Confirm all product selections against the current manufacturer TDS before specifying.
| Product | Brand | AS class | Elongation | Crack-bridging | Reinforcement mat required | Tile-over time | Damp substrate OK | Primary use |
|---|---|---|---|---|---|---|---|---|
| WPM 002 | ARDEX | Class III (AS 4858) | Confirm with TDS | Microfibre integral — confirm at junctions | Tape/fabric at junctions — no mat at field | 16–24 hrs (4 hrs non-critical) | No — damp-dry only | Under-tile balcony, terrace, wet area — internal and external |
| Mapelastic Smart | Mapei | Class II (AS/NZS 4858) | 170% | >2mm at 2mm DFT | Mapetex Sel or Mapenet 150 at all junctions | 5 days minimum | No — sound dry surface | Under-tile balcony, terrace, bathroom, pool |
| Mapelastic Foundation | Mapei | Confirm AS status with Mapei | Confirm with TDS | Confirm with TDS | Confirm with TDS | Confirm with TDS | Yes — formulated for damp concrete | Positive/negative pressure — retaining walls, pools, below-grade |
| K11 Flex | Davco / Laticrete | Confirm with TDS | Confirm with TDS | Confirm with TDS | Confirm at junctions with Davco | Confirm with TDS | Yes — designed for dampened substrates | Under-tile balcony, terrace, wet area, basement — internal and external |
| Nitoproof 410 | Fosroc / Parchem | Class III (wet areas) | Confirm with TDS | Confirm with TDS | Confirm with Parchem | Fast drying — confirm with TDS | No — sound dry substrate | Under-tile balcony, terrace, podium — exposed trafficable with Nitoproof Top Coat UV overcoat |
| Sikalastic-1K | Sika | Confirm AS 4858 with Sika | Confirm with TDS | Crack-bridging — confirm rating | Integral fibre reinforcement | Confirm with TDS | No — confirm with Sika | Concrete protection and waterproofing — tanks, basins, external above-ground concrete — not a two-component system |
Do not confuse cementitious flexible membranes with:
- Polyurethane and hybrid liquid membranes (ARDEX WPM 157, Sikalastic-487, Bostik Dampfix PU, Gripset P39 and similar) — these are polymer-based, not cement-based, and typically have higher elongation — listed on the liquid applied PU and hybrid membrane page
- Single-component acrylic and SBR membranes (Crommelin Wetite, Gripset 38FC and similar) — water-based polymer systems, not cementitious — listed on the liquid applied acrylic membrane page
- Crystalline waterproofing (Xypex, Krystol and similar) — penetrating admixture systems, not surface-applied membrane-forming products
- Rigid cementitious coatings — non-flexible cement coatings such as Maxseal Super or similar rigid tanking products — not the same as flexible two-part polymer-modified systems
- Epoxy moisture barriers — two-part epoxy primers applied under floor adhesives — these are moisture barriers, not waterproof membranes
- Sheet membranes — factory-manufactured sheet products (torch-on bitumen, self-adhesive butyl) — not liquid or trowel-applied systems
Disclaimer
This page provides general technical information only. Final product selection must be confirmed against the current manufacturer technical data sheet, project specification, substrate condition, exposure level, drainage, required finish, NCC requirements, AS 4858 and AS 4654 requirements where applicable, and applicator warranty conditions. Do not rely on this reference as a substitute for professional engineering or waterproofing consultant advice.