For movement and connection joints on concrete and masonry facades, Sikaflex Pro Polyurethane Sealant 300ml Cartridges provides a highly elastic, moisture-curing seal that accommodates joint shifting without losing adhesion. This one-part polyurethane sealant is formulated for connection joints on porous substrates and general sealing in both indoor and outdoor applications.
Sikaflex Pro cures by reacting with atmospheric moisture to form an elastic joint sealant with a movement capability of ±25%. This high flexibility allows the cured joint to absorb thermal expansion and contraction across a wide service temperature range of −40 °C to +70 °C. It is rated as Class 25 under ASTM C 920 and ISO 11600 F 25 LM, confirming its performance in demanding facade connection joints. The sealant also carries AS/NZS 4020:2018 approval for contact with potable water.
Sikaflex Pro is suitable for movement and connection joints across a variety of building materials, including:
Substrates must be clean, dry, sound, homogeneous, and free of oils, grease, dust, and loose particles. While the sealant adheres without primers for standard applications, critical or high-exposure joints require the following pre-treatments:
Insert a closed-cell, polyethylene foam backing rod to the required depth. Joint widths must be designed between 10 mm and 40 mm, maintaining a width-to-depth ratio of 2:1. Extrude the sealant into the joint, ensuring full contact with the joint sides to prevent air entrapment. Tool the sealant firmly against the joint sides. For a smooth finish, wet-tool using Sika Tooling Agent N. If dry-tooled, the surface will show a slightly structured, concrete-like finish. Remove any masking tape within the 170-minute skinning time. Clean tools immediately after use with Sika Remover-208; cured material can only be removed mechanically.
Yes, Sikaflex PRO is approved for potable water contact. It meets AS/NZS 4020:2018 for use in applications where it will be exposed to drinking water.
Sikaflex PRO offers a movement capability of ±25%. This allows it to accommodate significant expansion and contraction in joints without compromising the seal.
No, Sikaflex PRO is not recommended for use on natural stone. Refer to the product limitations to avoid potential issues.
Most conventional facade paint systems can be used over Sikaflex PRO. Conduct trials to confirm compatibility and allow the sealant to fully cure first. Non-flexible paints may crack if applied to the elastic sealant.
| Application | Key benefit | Primary trades |
|---|---|---|
| Movement joints in concrete and masonry facades | Accommodates ±25% joint movement, preventing cracking and ensuring long-term weathersealing. | Concrete contractors, bricklayers, facade installers |
| Connection joints on porous substrates | Forms a strong, elastic seal on common building materials, preventing moisture ingress and air leaks. | General builders, tilers, renderers |
| Potable water applications | AS/NZS 4020:2018 approval ensures safety and compliance for drinking water contact. | Plumbers, water treatment specialists |
| General indoor and outdoor sealing | Good workability and adhesion simplifies application across a broad range of typical sealing tasks. | General 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: This product is a combustible liquid and harmful to aquatic life.
Wear chemical-resistant, impervious gloves (butyl rubber/nitrile rubber recommended) and safety glasses. Follow AS/NZS 1337.1 for eye protection and AS 2210:3 for protective clothing (e.g., long-sleeved working clothing, long trousers).
Ensure adequate ventilation and/or engineering controls are in place to prevent exposure to vapours.
Store in original, unopened, undamaged packaging in dry conditions between +5 °C and +25 °C, protected from direct sunlight. Shelf life is 12 months from production date. Dispose of contents and container at an approved waste disposal plant. Clean tools immediately after use with Sika Remover-208 or Sika TopClean T; cured material must be removed mechanically.
Correct substrate preparation is critical for durable adhesion and long-term performance, preventing callbacks and ensuring a secure bond.
Surface prep: Substrate must be clean, dry, sound, and homogeneous. Ensure it is free from oils, grease, dust, and loose particles. For high-performance or critical joints, always pre-treat.
Primer: Required. Prime using Sika Primer-3 N applied with a brush. Allow a flash-off time of 30 minutes to 8 hours before sealing.
Surface prep: Substrate must be clean, dry, sound, and homogeneous. Ensure it is free from oils, grease, dust, and loose particles. For high-performance or critical joints, always pre-treat.
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: Substrate must be clean, dry, sound, and homogeneous. Ensure it is free from oils, grease, dust, and loose particles. For high-performance or critical joints, always pre-treat.
Primer: Required. Clean and pre-treat using Sika Aktivator-205. After flash-off, apply Sika Primer-3 N with a brush. Allow a further flash-off time of 30 minutes to 8 hours before sealing.
Surface prep: Substrate must be clean, dry, sound, and homogeneous. Ensure it is free from oils, grease, dust, and loose particles. For high-performance or critical joints, always pre-treat.
Primer: Required. 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 |
| 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% |
| Elastic Recovery | 90% approx. |
| Tear Propagation Resistance | 5.5 N/mm approx. |
| Service Temperature | -40 °C to +70 °C |
| Sag Flow | 0 mm (20 mm profile, 50 °C) |
| Ambient Air Temperature for Application | +5 °C to +40 °C, min. 3 °C above dew point temperature |
| Substrate Temperature for Application | +5 °C to +40 °C |
| Curing Rate | 3 mm/24 hours approx. (23 °C / 50% r.h.) |
| Skinning Time | 170 minutes approx. (23 °C / 50% r.h.) |
| Tooling Time | 150 minutes approx. (23 °C / 50% r.h.) |
| Flash Point | ca. 63 °C (closed cup) |
| Vapour Pressure | 0.01 hPa |
| Water Solubility | Insoluble |
Here are some common examples on where Sikaflex Pro Polyurethane Sealant 300ml Cartridges used by our customers.
