11
Download Product Data
For internal wet areas, balconies, pools, and retaining walls, RLA 2 Part Cementitious Membrane provides a rapid-drying, high-adhesion waterproofing barrier. It combines the structural durability of a cementitious system with the high flexibility of a pre-mixed liquid membrane, making it suitable for direct tile laying or screed placement over movement-prone structural substrates.
How it works
This two-component membrane cures to form a Class II flexible barrier with 214% elongation. It is independently tested to AS4858 and AS 4654.1 for internal and external wet areas, allowing a single product to span across interior shower trays, exterior facade walls, and fully submerged environments. The cured tan film provides an exceptionally stable keying surface for direct fixing of tiles using polymer-modified adhesives, or for laying sand-cement screeds. It is also tested to AS 4020 for contact with potable drinking water, making it suitable for concrete retention tanks and storage facilities.
Numbers that matter
- 1.2mm minimum dry film thickness (DFT): Achieved by applying a minimum of two coats at 0.75mm wet film thickness (WFT) per coat, ensuring reliable barrier performance under tiles or toppings.
- 1.5 litres/m² minimum coverage: The minimum required application rate across two coats to meet certified waterproofing thickness standards. One 40kg kit covers approximately 23m².
- 24-hour tile window: Allows tiling or screed application to commence just 24 hours after membrane application under standard conditions (23°C and 50% RH).
- 7-day full cure: The required curing window before filling ponds, pools, or water features for continuous immersion.
- 1-hour pot life: The working window of the mixed material at 23°C before it begins to set in the pail.
Where to use it
Suitable for installation over the following structurally sound and prepared substrates:
- Concrete (cured for at least 28 days)
- Cement render and sand-cement screeds (cured for at least 7 days)
- Compressed fibre cement sheeting and plasterboard
- Masonry and brickwork (pointed flush)
Required priming systems
The membrane must be applied over primed surfaces. Match the primer to the substrate condition:
- Porous and absorbent surfaces: Apply 1 to 2 coats of RLA Porous Primer at 1 litre per 8m² per coat.
- Non-porous surfaces: Apply 1 coat of RLA Non Porous Primer at 1 litre per 8 to 10m².
- Damp substrates or residual moisture: Where testing shows >80% RH (ASTM F2170) or >5% moisture content (ASTM F2659), apply 1 to 2 coats of RLA Moisture Seal barrier at 1 litre per 4m² per coat.
Joint detailing and system components
Different joint-sealing and bondbreaker options apply depending on whether the installation is dry, wet, or fully immersed:
- Immersed applications (pools, ponds, tanks): Must use Elastoproof Joint Band and Corners embedded in the wet first coat for bondbreaker transitions. Use Elastoproof Collars for pipes and penetrations.
- Non-immersed applications (bathrooms, balconies, facades): May use BRW PF Tape for bondbreakers, joints, and penetrations. RLA Max SMP 25 can be used to seal leak control flanges, penetrations, and to fill static cracks from 1mm up to 6mm flush before coating.
Limitations
- Do not apply when ambient or surface temperatures are below 5°C or above 35°C.
- Do not apply if rain is falling or imminent.
- Not suitable as a final trafficable wearing finish.
- Must not be left exposed in swimming pools or spas; the membrane must be tiled over.
- Do not use in areas subject to negative hydrostatic pressure.
- Do not mix the powder and liquid components by hand; an electric stirrer with a paddle mix attachment is required.
Frequently asked questions
Is RLA 2 Part suitable for potable water and immersion?
Yes, this membrane is suitable for permanent immersion in pools, ponds, and water features. It also holds AS 4020 potable-water approval for tanks and water storage facilities.
When can I tile or immerse after application?
Recoat after 2–4 hours. You can tile or screed after approximately 24 hours. Allow 7 days for full cure before immersion in water.
What film thickness is required for RLA 2 Part?
Apply two coats, each at approximately 0.75 mm wet film thickness, to achieve a minimum dry film thickness of 1.2 mm. This requires a target coverage of 1.5 L/m².
Which primer should I use with this membrane?
Select primers based on substrate conditions: RLA Porous Primer for absorbent surfaces, RLA Non-Porous Primer for dense surfaces. Use RLA Moisture Seal if residual moisture exceeds thresholds.
Can RLA 2 Part be used for negative hydrostatic pressure?
No, RLA 2 Part Cementitious Membrane is not designed or specified for applications involving negative hydrostatic pressure.
Applications and benefits
| Application | Key benefit | Primary trades |
|---|---|---|
| Internal and external wet areas, balconies | Class II flexibility (AS 4858/AS 4654.1) for movement, fast recoat times, tile-ready surface. | Waterproofers, tilers, builders |
| Planter boxes and retaining walls | Robust cementitious finish with strong adhesion to mineral-based substrates. | Builders, remedial contractors |
| Pools, ponds, and potable water tanks | Rated for permanent immersion and AS 4020 approved for drinking water contact. | Waterproofers, asset maintenance |
| Façade walls under tiles or stone | UV-stable membrane, suitable for direct fixing of tiles and stone. | Tilers, builders |
Applying RLA 2Part: Enhanced Protocols & Best Practices
-
Detailing & Bond Breakers
Seal junctions, joints and penetrations before field coating. Embed joint band into a wet coat or use self-adhesive tapes per system method. Use collars for pipes. Note some tapes/sealants are not suitable for immersed areas.
Pro Tip: Press out creases and air pockets when embedding bands/tapes; fully encapsulate with membrane. -
Mixing (Kit Components)
Part A (liquid) 20 L + Part B (powder) 2 × 10 kg. Add powder to liquid while mechanically mixing to a smooth, lump-free paste. Allow 5 min stand, then remix briefly. Do not hand-mix.
Timing: Pot life ~1 hour (shorter in warm conditions). Mix smaller batches as needed. -
Coating & Film Build
Apply the first coat by brush/roller to ~0.75 mm WFT. Once dry, apply the second coat at right angles, again to ~0.75 mm WFT. Verify with a wet film gauge to achieve ~1.2 mm DFT total (coverage target ~1.5 L/m²).
Pro Tip: Maintain even pressure and re-measure build across edges, corners and over detailing tapes. -
Dry Times & Overlays
Recoat 2–4 h, then tile/screed after ~24 h with polymer-modified adhesives. For immersion, allow ~7 days. Cooler temps and high RH extend times.
Pro Tip: For site-mixed screeds/renders over the membrane, dose with a proprietary bonding agent as specified.
How to apply RLA 2 PART Two Component Cementitious Membrane:
- Surface Preparation: Ensure all surfaces are clean, sound, smooth, dry, and free from contaminants. Mechanically remove any unsound layers or contaminants. Fill any defects, voids, or cracks.
- Priming: Apply the appropriate RLA primer based on the substrate's porosity: RLA Porous Primer for porous surfaces (1-2 coats), RLA Non Porous Primer for non-porous surfaces (1 coat), or RLA Moisture Seal for damp surfaces (1-2 coats). Allow primer to dry completely.
- Mixing: Pour half (10 litres) of Part A liquid into a clean 20L bucket. While mechanically stirring, slowly add one 10 kg bag of Part B powder and mix until smooth and lump-free. Allow to stand for 5 minutes and remix before use.
- First Coat Application: Using a brush or medium nap roller, apply an even first coat to the surface, achieving a minimum wet film thickness of 0.75mm (750 micron).
- Drying Time: Allow the first coat to dry completely, typically for 2-4 hours at 23°C and 50% RH. Drying times will vary with temperature and humidity.
- Second Coat Application: Apply a second coat at a right angle to the first coat, again achieving a minimum wet film thickness of 0.75mm (750 micron). This will result in a total minimum dry film thickness of 1.2mm.
- Detailing: Incorporate bond breaker tapes (e.g., Elastoproof Joint Band, BRW PF Tape) at all joints, junctions, and corners as per relevant Australian Standards (AS 3740 & AS 4654.1). Use Elastoproof Collars or BRW PF Tape for pipes and penetrations.
- Curing: Allow the membrane to cure fully before tiling or applying toppings. Polymer-modified adhesives can typically be used after 24 hours. Immersion in water should be delayed for 7 days.
Product limitations
- Not for: Applications where surface or ambient temperatures are outside 5–35 °C.
- Not for: Use as a trafficable or exposed finish. For pools and spas, this membrane requires tiling over.
- Not for: Areas subject to negative hydrostatic pressure.
- Consider: The correct RLA primer selection is critical for performance on porous, non-porous, and moisture-affected substrates.
Safety and handling
Personal protective equipment
Wear appropriate gloves, eye protection, and a suitable respirator during mixing and application. Avoid direct skin and eye contact.
First aid
- Eyes: Rinse immediately with water for several minutes. Seek medical advice.
- Skin: Wash thoroughly with soap and water. Remove contaminated clothing.
- Inhaled: Move to fresh air. Seek medical attention if symptoms persist.
- Swallowed: Rinse mouth. Do not induce vomiting. Seek urgent medical attention.
Storage and disposal
Maintain a 12-month shelf life by storing in unopened packaging. Keep containers off the ground in a dry area, away from direct sunlight.
Substrate guide
Proper substrate preparation and priming are essential for adhesion and performance of the RLA 2 Part Cementitious Membrane.
Concrete, render, screed
Surface prep: Ensure the surface is clean, sound, smooth, and dry. Remove all dust, oils, curing agents, release residues, and laitance. Rectify any voids or defects and confirm correct falls. New concrete requires 28 days of cure, while render and screed need 7 days.
Primer: Required. Use RLA Porous Primer for absorbent surfaces or RLA Non-Porous Primer for dense, smooth surfaces. Apply RLA Moisture Seal where residual moisture exceeds ASTM F2170/F2659 thresholds.
Masonry, CFC, plasterboard
Surface prep: Point masonry joints flush, repair any damage, and ensure surfaces are level, clean, and dry. Confirm the substrate is fit for purpose according to building standards.
Primer: Required. Select an RLA primer based on the substrate's porosity and density, following the guidance for concrete and render. Consider RLA Moisture Seal if moisture conditions demand it.
RLA 2 Part Cementitious Membrane Physical Properties
| Property | Value |
|---|---|
| Appearance | Part A: white liquid; Part B: light grey powder; Dry film: tan |
| Density | 1.4 g/cm³ |
| Tensile Strength | 1.2 MPa |
| Elongation | 214% |
| Full Cure | 7 days |
| Recoat Time | 2–4 h |
| Tiling Ready | 24 h |
| Water Vapour Transmission | 3.1 g/(24 h·m²) |
| Mix Ratio | 20 L liquid + 2 x 10 kg powder; Mechanical mix to smooth paste |
| Pot Life | 1 h at 23°C |
| Coverage Rate | 23 m² (40 kg kit) |
| Primer Guidance | RLA Moisture Seal, 1–2 coats, 1 L/4 m²/coat, Moisture >80% RH or >5% |
| Classification | Class II Flexible (AS 4858/AS 4654.1) |
| Standards | AS 4020 |
| Packaging | 40 kg kit (20 L liquid + 2 x 10 kg powder) |
| Shelf Life | 12 months unopened |
| Storage Conditions | Store dry, Off ground, Out of direct sun |
| Application Coats | 2 |
| Dry Film Thickness Total | 1.2 mm |
| Water Absorption | 1.9% |
| Wet Film Thickness Per Coat | 0.75 mm |
- Choosing a selection results in a full page refresh.