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RLA 2 Part: A Technical Overview
RLA 2 Part is a premium two-component cementitious membrane that delivers the ultimate combination of toughness and flexibility. It masterfully blends the durable, high-adhesion characteristics of a cement-based system with the flexible, crack-resistant properties of an advanced acrylic polymer liquid. This versatile formulation is engineered to provide a fully compliant, seamless waterproofing barrier for an exceptionally broad range of applications. From internal wet areas and external balconies to fully immersed swimming pools and AS 4020 certified potable water tanks, RLA 2 Part offers a single-system solution that provides engineered certainty and uncompromising performance.
214%
Elongation (AS 4858). A Class II flexibility rating that accommodates anticipated structural movement and substrate shifts, preventing cracks and ensuring a continuous, durable waterproof barrier.
Core Features & Specifications
- Fully Certified to Australian Standards: Independently tested to AS 4858 (Class II), AS 4654.1 (External), and AS 4020 (Potable Water), providing documented proof of performance for specifiers.
- Suitable for Full Immersion: Engineered for continuous water immersion in swimming pools, ponds, and water features after a 7-day cure, providing a tough and durable barrier.
- Fast Drying & Recoat Time: Ready for recoat in just 2-4 hours and tiling or screeding in 24 hours, significantly accelerating project timelines for follow-on trades.
- High Adhesion Strength: Creates a tenacious bond to correctly primed substrates, ensuring the membrane system acts as a single, monolithic layer that resists delamination.
- UV Stable Formulation: Can be left exposed to UV light during the construction phase without degradation, providing greater flexibility with project scheduling.
The RLA 2 Part Advantage
- Ultimate Project Versatility: Use a single, trusted system for a huge range of applications – from showers and balconies to retaining walls and potable water tanks, simplifying inventory and training.
- Achieve Compliance with Confidence: Extensive third-party testing to key Australian waterproofing standards eliminates compliance risks and provides engineered certainty for your projects.
- Accelerate Project Schedules: The fast-drying formulation allows for subsequent trades (tilers, screeders) to get on-site sooner, improving overall job efficiency and profitability.
- Tough & Durable Finish: The cementitious base provides a robust, durable membrane that resists damage during the construction process and provides a long-service life.
Proactive Troubleshooting
Scenario: Applying to an Unprimed or Incorrectly Primed Substrate
Potential Outcome: Poor adhesion, blistering, or complete delamination of the membrane. Porous substrates can draw water from the mix too quickly, causing pin-holing and a compromised, leaky film.
Adheseal Best Practice: Priming is mandatory. Use RLA Porous Primer on absorbent surfaces like concrete, RLA Non Porous Primer on dense substrates like CFC sheeting, or RLA Moisture Seal on damp substrates per moisture test results.
Scenario: Insufficient Film Thickness (DFT)
Potential Outcome: The membrane fails to meet the performance requirements of a Class II membrane. It will not bridge cracks effectively and is highly susceptible to developing pinholes, leading to inevitable leaks and costly callbacks.
Adheseal Best Practice: Apply a minimum of two coats to achieve a total Dry Film Thickness (DFT) of 1.2mm. Use a wet film thickness gauge during application to ensure the minimum coverage of 1.5 litres/m² is consistently met across the entire area.
Applications in Practice: Trade Scenarios
For Waterproofers — Balcony & External Wet Areas
The Professional's Challenge
Deliver a fully compliant AS 4654.1 system that can withstand external exposure and substrate movement, while ensuring a uniform film build for reliable, long-term performance.
The Adheseal Solution: Engineered Certainty in Practice
The Class II flexibility of RLA 2 Part handles typical balcony movement. Its UV stability and fast cure time make it a reliable choice for external applications. A consistent two-coat application, verified with a WFT gauge, ensures compliance is met.
Best Practice Note
Detail all perimeters, junctions, and outlets with the Elastoproof Joint Band system, fully embedded between the two membrane coats, to create a seamless, monolithic waterproof barrier as required by the standard.
For Pool Builders — Immersed Applications
The Professional's Challenge
Construct a durable, tile-ready waterproof shell that performs under the constant hydrostatic pressure of permanent immersion and is certified safe for use in pools, ponds, and potable water tanks.
The Adheseal Solution: Engineered Certainty in Practice
RLA 2 Part is purpose-built for immersion, providing a tough, durable finish. Its AS 4020 certification provides the compliance needed for potable water applications. The system is ready for tiling after 24 hours and full immersion after a 7-day cure.
Best Practice Note
Ensure concrete substrates have cured for a minimum of 28 days before priming and application. The full 7-day cure time for the membrane is critical and must be observed before filling to ensure maximum durability.
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
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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 |
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