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For movement and connection joints in concrete and masonry facades, Sikaflex PRO is a one-component, moisture-curing polyurethane sealant. It provides a reliable seal for expansion joints on porous substrates and is suitable for both indoor and outdoor general sealing applications, including potable water systems with AS/NZS 4020:2018 potable-water approval.
Sikaflex PRO cures upon exposure to atmospheric moisture to form an elastic joint sealant with a movement capability of ±25%. This elasticity allows the cured joint to absorb thermal expansion and structural contraction without losing adhesion to the joint faces. It possesses high tear propagation resistance, preventing minor surface punctures from splitting under tension, and maintains a stable seal across a service temperature range of −40 °C to +70 °C.
Sikaflex PRO adheres without primers to many common building materials. However, for optimum adhesion in critical or highly stressed joint applications, specific pre-treatments apply:
Before application, insert a closed-cell, polyethylene foam backing rod to regulate the joint depth. Extrude the sealant into the joint, ensuring full contact with the joint faces to prevent air entrapment. Tool the sealant firmly against the joint sides. If dry-tooled, the sealant cures to a slightly structured, concrete-like finish; wet-tooling with Sika Tooling Agent N produces a smooth surface. Clean uncured tools and equipment immediately with Sika Remover-208; cured material can only be removed mechanically.
Yes, Sikaflex PRO is approved to AS/NZS 4020:2018 for contact with potable water. This makes it suitable for sealing applications within drinking water infrastructure where this standard is required.
Sikaflex PRO has a movement capability of ±25%, tested to ISO 9047 and ASTM C 719 standards. This ensures it can accommodate significant joint movement in facades and other structures without failing.
No, Sikaflex PRO is not recommended for use on natural stone substrates. This limitation helps avoid potential issues like staining or adhesion problems specific to natural stone.
Sikaflex PRO can typically be over-painted with most conventional facade coating paint systems. Always conduct preliminary trials to confirm compatibility, and allow the sealant to fully cure for best results. Non-flexible paints may affect sealant elasticity.
| Application | Key benefit | Primary trades |
|---|---|---|
| Movement joints in concrete and masonry facades | Accommodates ±25% joint movement to prevent cracking and maintain weather resistance in exterior applications. | Facade contractors, Builders, Concrete repairers |
| Connection joints on porous substrates | Ensures reliable, elastic sealing with good adhesion to common building materials, reducing callback risk. | General builders, Carpenters, Drywallers |
| Sealing joints in contact with potable water | AS/NZS 4020:2018 approval confirms suitability and safety for use in drinking water infrastructure. | Plumbers, Civil contractors, Water utilities |
| General indoor and outdoor sealing applications | Durable polyurethane formulation with wide service temperature range (−40 °C to +70 °C) ensures long-term performance. | Builders, Renovators, Maintenance teams |
The foundation of a durable seal is a properly prepared substrate. Ensure the surface is structurally sound, clean, and dry.
Use a wire brush, grinding, or sandblasting to remove all laitance, dust, and loose material. Remove all contaminants like form-release agents, curing compounds, and old sealant residues.
Clean with a suitable solvent and a clean, lint-free cloth. For metals, light abrasion may be required to remove oxidation. Always perform a final wipe to remove any residues.
For critical applications, priming is essential for optimal adhesion. Backing rods are non-negotiable for controlling sealant depth and preventing three-sided adhesion.
Apply the recommended Sika primer or activator in a thin, continuous film using a brush or clean cloth. Avoid ponding or over-application.
Insert a closed-cell polyethylene foam backing rod to the required depth to achieve the correct width-to-depth ratio (typically 2:1). Ensure the rod is compressed by approx. 25% to hold it in place.
Proper application and tooling are crucial for a professional finish and long-term performance.
Cut the nozzle to the required bead size. Extrude the sealant into the joint from the base, ensuring continuous, uniform application and avoiding any air entrapment.
Firmly tool the sealant against the joint sides and backing rod. Use a spatula or slicker with a suitable tooling agent (e.g., Sika® Tooling Agent N) to create a smooth, concave finish that sheds water.
Warning: Combustible liquid. Harmful to aquatic life.
Wear chemical-resistant gloves (butyl rubber/nitrile recommended), safety glasses, and protective clothing made of cotton (refer to AS 2210:3) to prevent skin and eye contact. If ventilation is inadequate, wear respiratory protection.
Ensure adequate ventilation or use engineering controls to prevent exposure to vapours during application and curing.
Store Sikaflex PRO in its original, undamaged, sealed packaging in dry conditions, protected from direct sunlight, at temperatures between +5 °C and +25 °C. Shelf life is 12 months. Dispose of contents and container at an approved waste disposal plant, avoiding release into the environment or waterways.
Correct substrate preparation is critical for Sikaflex PRO's performance, ensuring optimal adhesion and long-term joint integrity.
Surface prep: Substrate must be clean, dry, sound, and homogeneous, free from oils, grease, dust, and loose particles.
Primer: Required for optimal adhesion in critical or highly stressed applications. Use Sika® Primer-3 N applied with a brush. Allow a flash-off time of 30 minutes to 8 hours before sealing.
Surface prep: Clean surfaces thoroughly.
Primer: Required for optimal adhesion. Clean and pre-treat using Sika® Aktivator-205 wiped on with a clean towel. Allow a flash-off time of 15 minutes to 6 hours before sealing.
Surface prep: Clean surfaces thoroughly.
Primer: Required for optimal adhesion. Clean and pre-treat using Sika® Aktivator-205, then apply Sika® Primer-3 N with a brush. Allow Sika® Aktivator-205 to flash-off for 15 minutes to 6 hours, then Sika® Primer-3 N for 30 minutes to 8 hours before sealing.
Surface prep: Clean surfaces thoroughly.
Primer: Required for optimal adhesion. Clean and pre-treat using Sika® Primer-215 applied with a brush. Allow a flash-off time of 30 minutes to 8 hours before sealing.
| Property | Value |
|---|---|
| Composition | Polyurethane |
| Packaging | 600 ml foil pack |
| Shelf Life | 12 months from production date |
| Storage Conditions | Dry, protected from direct sunlight, +5 °C to +25 °C |
| Colours | White, Off White, Sandstone, Pale Brown, Japan Beige, Grey, Dark Grey, Brick Red, Redwood, Black, Dark Amber |
| Density | 1.25 kg/l (approx.) |
| Shore A Hardness | 25 (approx. after 28 days) |
| Secant Tensile Modulus at 100% Elongation (23 °C) | 0.35 N/mm² (approx.) |
| Secant Tensile Modulus at 100% Elongation (-20 °C) | 0.50 N/mm² (approx.) |
| Tensile Strain at Break | 750% (approx.) |
| Movement Capability | ± 25% (ISO 9047, ASTM C 719) |
| Elastic Recovery | 90% (approx.) |
| Tear Propagation Resistance | 5.5 N/mm (approx.) |
| Service Temperature | −40 °C to +70 °C |
| Minimum Joint Width | 10 mm |
| Maximum Joint Width | 40 mm |
| Width to Depth Ratio | 2:1 (for most applications) |
| Sag Flow | 0 mm (20 mm profile, 50 °C) |
| Ambient Air Temperature | +5 °C to +40 °C (min. 3 °C above dew point) |
| Substrate Temperature | +5 °C to +40 °C |
| Curing Rate | 3 mm/24 hours (approx. at 23 °C / 50% r.h.) |
| Skinning Time | 170 minutes (approx. at 23 °C / 50% r.h.) |
| Tooling Time | 150 minutes (approx. at 23 °C / 50% r.h.) |
Here are some common examples on where Sikaflex Pro Polyurethane Sealant 600ml Sausages used by our customers.
