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RLA Moisture Seal: A Technical Overview
RLA Moisture Seal is a two-part, water-based epoxy primer and barrier coating engineered for demanding moisture control applications. Withstanding up to 25 metres of hydrostatic head (250 kPa), it provides outstanding adhesion to damp or “green” concrete and is compatible with a full range of RLA waterproofing membranes, adhesives, and levelling compounds. Its low-VOC, solvent-free formulation meets AS 4020 for potable water use, enabling safe use in tanks and reservoirs. Extended pot life and easy roller, broom, or squeegee application make it a reliable choice for waterproofers, tilers, and remedial contractors.
Core Features & Specifications
- Water-based, solvent-free, and low VOC – safe for enclosed spaces and environmentally responsible.
- Withstands up to 25m / 250 kPa hydrostatic pressure – suitable for basements and submerged structures.
- Bonds to damp and freshly cured concrete – speeds up project timelines.
- Complies with AS 4020 – approved for potable water applications.
- Extended pot life for easy application across larger areas.
- Fully compatible with RLA membranes, coatings, adhesives, and levelling compounds.
The RLA Moisture Seal Advantage
- Eliminates the risk of blistering or delamination caused by trapped moisture vapour.
- Delivers reliable long-term protection for high-value finishes.
- Enables confident installation of finishes over damp substrates.
- Reduces downtime by allowing application on “green” concrete.
Proactive Troubleshooting
Scenario: Applying over active water leaks
Potential Outcome: Loss of adhesion and coating failure due to hydrostatic pressure breach.
Adheseal Best Practice: Seal active leaks first with a rapid-setting hydraulic repair mortar before applying Moisture Seal.
Scenario: Inadequate surface cleaning
Potential Outcome: Reduced adhesion and premature coating breakdown.
Adheseal Best Practice: Mechanically remove contaminants, laitance, and weak material; ensure substrate is structurally sound.
Applications in Practice: Trade Scenarios
For Waterproofers (Specifier/Engineer): Basement Waterproofing with Rising Damp
The Professional's Challenge
Basements subject to negative hydrostatic pressure can suffer efflorescence, blistering, and coating failure if the moisture barrier is insufficient.
The Adheseal Solution: Engineered Certainty in Practice
Apply two coats of Moisture Seal at 1 L/5 m² per coat, achieving a minimum 200 μm dry film thickness, with cross-directional application for complete coverage.
Best Practice Note
Always sand-seed the second coat when overcoating with cementitious toppings to ensure optimal keying and bond strength.
For Tilers (On-Site Applicator): Preventing Tile Delamination over Damp Slabs
The Professional's Challenge
Installing tiles over slabs with residual moisture risks adhesive breakdown and failure of the tile system.
The Adheseal Solution: Engineered Certainty in Practice
Apply two coats at 1 L/5 m² per coat, sand-seeding the second coat at 750 g/m² to achieve a 90% coverage, then install RLA polymer-modified adhesive within 72 hours.
Best Practice Note
Use a wet film thickness gauge during application to verify each coat meets the specified film build.
Frequently Asked Questions
Can RLA Moisture Seal be applied to damp concrete?
Yes, RLA Moisture Seal is designed to bond to damp and “green” concrete surfaces. This capability reduces project delays by allowing application before full substrate curing, provided the surface is clean and structurally sound.
Is it suitable for potable water storage?
Yes. RLA Moisture Seal complies with AS 4020, making it safe for use in potable water tanks and reservoirs once fully cured.
How soon can I apply finishes after Moisture Seal?
Finishes should be applied within 72 hours of Moisture Seal drying under normal ambient conditions. Beyond this, light sanding or re-priming may be required to ensure adhesion.
What is the coverage per 20L kit?
A 20L kit covers approximately 50 m² in two coats as a moisture barrier. Coverage may vary depending on substrate porosity and condition.
Can it be used as a trafficable surface?
No. Moisture Seal must always be overcoated or covered, as it is not designed for permanent foot or vehicular traffic exposure.
Applications & Benefits
| Application / Use Case | Key Benefit | Primary Trades |
|---|---|---|
| Basement waterproofing | Withstands high hydrostatic pressure | Waterproofers, Builders |
| Tiling over damp slabs | Prevents adhesive breakdown | Tilers |
| Potable water storage | Complies with AS 4020 for safe drinking water | Waterproofers |
Applying RLA Moisture Seal: Enhanced Protocols & Best Practices
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Mixing
Combine equal parts (1:1 by volume) of Part A and Part B. Mix for at least 3 minutes at low-medium speed until fully homogenous. Allow 5 minutes to settle before use.
Timing: Pot life is approximately 2 hours at 23°C, 50% RH.Pro Tip: Mix only what can be applied within pot life to prevent waste. -
Application
Apply with squeegee, stiff broom, or medium/long nap roller, ensuring complete substrate coverage and filling of pinholes.
Timing: Recoat after 4 hours; finishes can be applied after 24 hours.Pro Tip: Use a wet film gauge to confirm film thickness meets specification.
Limitations & Safety
Product Limitations
Do not apply below 10°C or above 35°C.
Not suitable as a finished UV-exposed coating.
Not a trafficable surface — must be overcoated or covered.
Safety & Handling Requirements
Personal Protective Equipment
Wear nitrile gloves, safety glasses, and long sleeves to avoid skin and eye contact.
Ventilation Requirements
Use in well-ventilated areas. In enclosed spaces, ensure adequate airflow during curing.
Emergency First Aid
Eyes:
Rinse immediately with plenty of water and seek medical advice.
Skin:
Wash with soap and water. Remove contaminated clothing.
RLA Moisture Seal Application Guide
Concrete & Concrete Block
Surface Preparation
Ensure surfaces are clean, structurally sound, and free from contaminants, laitance, and curing compounds. Cure new concrete for at least 28 days where possible, unless using on “green” concrete as specified.
Primer Requirements
No primer required
Apply Moisture Seal directly as per coverage guidelines.
Masonry & Render
Surface Preparation
Point masonry flush and repair voids, cracks, and surface defects. Cure cement render/screeds for at least 7 days before application.
Primer Requirements
No primer required
Direct application with specified film thickness is recommended.
Timber
Surface Preparation
Ensure surface is dry, clean, and free of loose fibres or coatings. Mechanically sand if required for adhesion.
Primer Requirements
No primer required
Apply as per moisture barrier guidelines.
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