Sikaflex 1a is a premium-grade, high performance, moisture-cured, one-component, polyurethane-based, non-sag elastomeric sealant.


  • Ideal for: Weatherproofing of joints between brickwork, blockwork, masonry, wood and concrete or metal frames; joints in walls, floors, balconies, around window or door frames: expansion joints; roofing.

  • Eliminates time, effort, and equipment for mixing, filling cartridges and cleaning of equipment.

  • High elasticity - Cures to a tough, durable, flexible consistency with exceptional cut and tear resistance.

  • Excellent adhesion - Bonds to most construction materials without primer in most cases.

  • Excellent resistance to aging, weathering.

  • Proven in tough climates around the world.

  • Resists fuel, mineral oils, and dilute minerals, plant and animal fats.

  • Odourless, non-staining, can be painted over with water, oil, and rubber-base paints. Since some paints dry slowly and the surface may remain slightly tacky, a preliminary test is essential.

  • Meets CAN/CGSB 19.13-M87, Classification MCG-2-25-B-N.

  • Meets Federal Specification TT-S-00230C, Type II, Class A.

  • Meets ASTM C 920 Type S, Grade NS, Class 25.

  • Jet fuel resistant.

  • NSF approved for potable water contact.

  • Urethane based, suggested by EPA for radon reduction.

  • USDA approved. Chemically acceptable to the U. S. Department of Agriculture for use in meat and poultry processing area under federal inspection.

  • Canadian Food Inspection Agency acceptance.

  • Ministry of Transport Québec acceptance.

  • SWRI validated. 

Where to Use


  • Designed for all types of joints with maximum depth of 13 mm (1/2 in) and a maximum expansion of 35%.

  • Excellent for small joints and fillets: windows, door frames, reglets, flashing, glazing, and many construction adhesive applications.

  • Suitable for vertical and horizontal joints; readily placeable at 4°C (39°F).

  •  Many applications as an elastic adhesive between materials with dissimilar thermal coefficients of expansion.

  • Submerged conditions such as canal and reservoir joints.