Sikaflex 11 FC + Polyurethane Adhesive and Sealant

For horizontal and vertical joints that experience physical movement, or assembly jobs requiring a direct bond between concrete, masonry, stone, ceramic, wood, metal, or glass, Sikaflex 11 FC + Polyurethane Adhesive and Sealant provides a single-component, elastic polyurethane barrier and adhesive. Formulated with i-Cure technology, it cures on exposure to atmospheric moisture to form an elastic joint sealant and high-strength adhesive suitable for internal and external building work.

Dual-action elastic bonding and sealing

The product functions simultaneously as a flexible adhesive and a non-sag joint sealant. The polyurethane chemistry delivers an elastic recovery of approximately 80%, allowing bonded components and sealed joints to absorb joint movement, vibrations, and thermal expansion without cohesive or adhesive failure. It seals joints from 10 mm to 35 mm wide, maintaining a 2:1 width-to-depth ratio for facade joints. The cured sealant resists weathering and mechanical stress, can be sanded smooth once cured, and is pick-resistant for improved security in exposed areas.

Numbers that matter

• ±35% movement capability (ASTM C 719): Absorbs significant thermal expansion and contraction across joints in concrete, masonry, and metal facades without tearing.
• ~3.5 mm per 24 hours cure rate (at +23°C / 50% R.H.): Controls the depth of cure over time; final bonding strength is reached within 24 to 48 hours depending on adhesive thickness and climate.
• ~70 minutes skinning time (at +23°C / 50% R.H.): Establishes a practical working window to tool joint edges or realign bonded elements before the surface skins.
• ~1.5 N/mm² tensile strength (ISO 37) & ~700% elongation at break: High structural elasticity to hold heavy components under load while stretching without rupturing.
• <1 g/L VOC content: Very low emissions meeting Green Star Design & As Built V1.3-13.1.1B and Green Star Interiors V1.3-12.1.1B requirements.

Where to use it

Sikaflex 11 FC + bonds and seals common building materials, including:

• Concrete and masonry: Sealing connection joints, perimeter joints around windows, and crack-control joints.
• Reconstituted, cast, or natural stone: Bonding panels and decorative elements (contact Sika Technical Services before application).
• Ceramics, glass, and wood: Internal and external fit-outs, cabinetry, and cladding joints.
• Metals: Anodised aluminium, stainless steel, galvanised steel, copper, brass, and bronze.

Limitations

• Substrate exclusions: Do not use on bituminous substrates, natural rubber, EPDM rubber, or materials that leach oils, plasticisers, or solvents. Do not use on PE, PP, PTFE (Teflon), or certain plasticised plastics.
• Immersion and wet areas: Do not use to seal joints in and around swimming pools, joints under water pressure, or areas of permanent water immersion. Do not use for sanitary joints.
• Glazing limits: Do not use to seal glass windows or for bonding glass if the bond line is exposed to sunlight.
• Structural and floor joints: Do not use for structural bonding or for trafficked floor joints.
• Application limits: Full surface applications are not recommended as the inner layer of the adhesive may not cure. Always use mechanical fixings alongside the adhesive for overhead applications or exceptionally heavy components.
• Painting and UV: Non-flexible paint systems can restrict sealant elasticity and cause the paint film to crack. Colour variations may occur under UV radiation or chemical exposure (especially white), which is aesthetic and does not affect durability.
• Chemical interference: Do not expose uncured sealant to alcohol-containing products, as they interfere with the cure reaction.

How to apply

For standard applications, the substrate must be clean, dry, sound, and mechanically prepared to remove weak material, cement laitance, and old coatings.

Priming and Pre-treatment:

• Concrete, bricks, and cement renders: Prime with Sika Primer-3 N. Avoid excessive application to prevent puddling in the joint.
• Aluminium, stainless steel, galvanised steel, and glazed tiles: Lightly abrade with a fine pad, clean, and pretreat with Sika Aktivator-205 using a clean cloth.
• Copper, brass, bronze, and titanium-zinc: Lightly abrade, clean, pretreat with Sika Aktivator-205, allow to dry, then brush-apply Sika Primer-3 N.
• PVC: Clean and prime using Sika Primer-215.

Bonding: Apply the adhesive in triangular beads, strips, or spots spaced a few centimetres apart. Position and press the component by hand before skinning occurs. Temporary tape, wedges, or supports can be used to hold heavy assemblies during initial cure.

Sealing: Insert a closed-cell, polyethylene foam backing rod to control joint depth. Extrude the sealant firmly into the joint to ensure complete contact with the joint walls. Tool the sealant immediately using a compatible solvent-free tooling agent (such as Sika Tooling Agent N) to flush the joint and ensure wet-edge wet-out.

Cleanup: Clean uncured residue from tools and application equipment immediately using Sika Remover-208. Clean skin with Sika Cleaner-350H. Cured adhesive can only be removed mechanically.