Sikaflex Pro Polyurethane Sealant 600ml Sausages

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.

How it works

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.

Numbers that matter

• ±25% movement capability (ISO 9047 / ASTM C 719): Absorbs significant joint expansion and contraction on concrete panels and masonry facades.
• 750% tensile strain at break (ISO 37): High elongation capability that prevents the sealant from tearing under extreme joint opening.
• 150-minute tooling window: Ample working time to tool the joint face and achieve a neat finish before the sealant begins to skin.
• 3 mm per 24 hours cure rate: Standard deep-cure rate at 23 °C and 50% relative humidity, allowing joint design planning for service exposure.
• 10 mm to 40 mm joint width limits: The required design boundary, maintaining a strict 2:1 width-to-depth ratio for standard facade joints.

Where to use it

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:

• Porous substrates: Concrete, aerated concrete, cement-based renders, mortars, and bricks. Prime with Sika Primer-3 N and allow 30 minutes to 8 hours flash-off time.
• Non-porous metals and glazing: Aluminium, anodised aluminium, stainless steel, galvanised steel, powder-coated metals, and glazed tiles. Clean and pre-treat with Sika Aktivator-205, allowing 15 minutes to 6 hours flash-off time.
• Other metals: Copper, brass, and titanium-zinc. Pre-treat with Sika Aktivator-205, then apply Sika Primer-3 N. Allow 30 minutes to 8 hours flash-off.
• PVC: Clean and pre-treat using Sika Primer-215, allowing 30 minutes to 8 hours flash-off.

Limitations

• Natural stone: Do not use Sikaflex PRO on natural stone, as staining or migration may occur.
• Bituminous and rubber substrates: Do not use on bituminous substrates, natural rubber, EPDM rubber, or building materials that bleed oils, plasticisers, or solvents.
• Water exposure: Do not use in and around swimming pools, for joints under water pressure, or for permanent water immersion.
• Painting: Non-flexible paint systems may impair sealant elasticity and lead to cracking of the paint film. Test paint compatibility before full application.
• Colour variations: White and light colours may yellow over time when exposed to UV radiation, chemicals, or high temperatures. This change is purely aesthetic and does not affect technical performance.
• Cure interference: Do not expose uncured sealant to alcohol-containing products, as they will disrupt the curing reaction.

Application and joint design

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.