When construction joints on concrete and masonry facades require professional-grade sealing, Sikaflex PRO delivers the right fit. It's built for the constant movement and exposure these structures endure, ensuring durability without compromise. For potable water infrastructure, it provides peace of mind with the necessary AS/NZS 4020 certification. This 1-component polyurethane sealant provides reliable flexibility and adhesion where it matters most.

Why this product exists

Sikaflex PRO is a professional 1-component, moisture-curing polyurethane sealant specifically engineered for the demands of movement and connection joints in construction. It handles the dynamic nature of building materials like concrete and masonry, where thermal expansion and contraction are constant. Its formulation ensures strong, flexible bonds on porous substrates, making it a go-to for durable facade work and general sealing where professional performance is non-negotiable.

The numbers that matter

• Movement capability of ±25%: This rating, certified to ISO 9047 and ASTM C 719, ensures the sealant can accommodate significant joint movement without cohesive failure. For a 20mm wide joint, it handles 5mm of expansion and contraction, preventing splits and gaps in dynamic facade elements.
• Shore A hardness of 25 (approx.): This indicates a highly elastic material that remains flexible after curing. It's firm enough to resist light traffic and impact but soft enough to absorb structural movement effectively.
• Tensile strain at break of 750% (approx.): With a 7.5x elongation capacity beyond its rated movement, this provides a substantial safety margin. This ensures the sealant maintains its integrity even under unexpected or extreme joint stresses.
• Curing rate of 3mm per 24 hours (approx.): This steady moisture-curing rate allows for a predictable schedule on site. The 170-minute skinning time and 150-minute tooling time provide ample working window to achieve a professional finish before the surface hardens.

What it's like to use

Sikaflex PRO is formulated for good workability, allowing for smooth extrusion and precise placement into joints. Prepare substrates to be clean, dry, and sound. Always use a compatible backing rod, such as the Adheseal backer rod range, to control joint depth and prevent three-sided adhesion. Extrude the sealant firmly into the joint, ensuring full contact with the joint sides to avoid air entrapment. For neat lines, use masking tape and remove it within the skin time. Tooling with a compatible agent like Sika Tooling Agent N will achieve a smooth finish. Clean tools and equipment immediately after use with Sika Remover-208.

Where this product excels

• Facade movement joints: Ideal for the dynamic joints in concrete and masonry facades, where its ±25% movement capability prevents cracking and ensures long-term weatherproofing against thermal expansion and contraction.
• Connection joints around fenestrations: Provides a durable, flexible seal around windows and doors on porous substrates, maintaining weather integrity and accommodating minor building settlement.
• Potable water structures: Certified to AS/NZS 4020:2018, this sealant is a critical choice for sealing joints in tanks, pipelines, and other infrastructure that will be in contact with drinking water.
• General outdoor and indoor sealing: Its robust formulation and adhesion to various common building materials make it suitable for a wide range of non-specialised sealing tasks across a construction project.

How it fits in a real system

Sikaflex PRO typically forms the final sealing layer in critical construction joints. While it adheres well to many substrates without primers, for optimum adhesion in high-performance applications like multi-story buildings, highly stressed joints, or areas of extreme weather exposure, primers are specified. For porous substrates such as concrete, aerated concrete, or cement-based renders, a primer like Sika Primer-3 N is applied by brush before sealing. On non-porous surfaces like aluminium or stainless steel, a surface activator such as Sika Aktivator-205 prepares the substrate for optimal adhesion, sometimes followed by Sika Primer-3 N for other metals like copper or brass. This staged preparation ensures the sealant performs to its full potential.

Choose this when

• When sealing movement or connection joints in concrete or masonry facades requiring ±25% movement capability.
• When the application demands AS/NZS 4020:2018 certification for contact with potable water.
• When a paintable sealant is preferred for facade work, ensuring compatibility with the chosen paint system through prior testing.
• When a reliable, single-component polyurethane sealant is needed for general indoor or outdoor construction sealing.

Don't use this when

• Not for: Natural stone, as it may cause staining or discolouration.
• Not for: Substrates that might bleed oils, plasticisers, or solvents, such as bituminous materials, natural rubber, or EPDM rubber.
• Not for: Joints in and around swimming pools, or for areas under water pressure or permanent water immersion.
• Not for: Joints requiring movement beyond its ±25% capacity, which would lead to premature failure.