Description
Sikaflex 15 LM sealant is a one-component, low-modulus polyurethane for vertical and non-sag construction joints that need substantial movement capability. This Redwood Tan 10.1 oz cartridge is ready to gun without mixing. It bonds to common construction materials and cures into a flexible joint that can accommodate movement between similar or dissimilar substrates.
Where Sikaflex 15 LM Sealant Is Used
Typical applications include joints in concrete wall and panel systems, window and door perimeters, reglets, flashing details, roofing transitions, facades, and exterior insulation finish systems. The low modulus helps the cured sealant move with the joint instead of transferring concentrated stress into the adjoining surface. Its non-sag body keeps the bead in place on vertical work while installers tool the joint for full contact with both sidewalls.
Application and Joint Design
Joint walls should be sound, clean, dry, and free of frost, oil, grease, curing compounds, and loose material. Install backer rod or bond-breaker tape to prevent three-sided adhesion. Apply the sealant from the bottom of the joint with a steady flow, keeping the nozzle in the bead to reduce trapped air. Sika recommends a joint thickness between 1/4 inch and 1/2 inch and a width-to-depth relationship of roughly 2:1. Application temperatures are 40 to 100 degrees F, with the substrate above the dew point.
Performance Specifications
| Property | Detail |
|---|---|
| Brand | Sika |
| Product | Sikaflex-15 LM |
| Chemistry | One-component polyurethane |
| Color | Redwood Tan |
| Package | 10.1 oz cartridge |
| Movement capability | +100 / -50 percent per ASTM C719 |
| Service temperature | -40 to 170 degrees F |
| Tack-free time | 2 to 6 hours |
| Final cure | 7 to 10 days under stated conditions |
Browse related sealants and adhesive sealants from Chemical Concepts. For current application limits, test methods, and substrate guidance, consult Sika technical resources before specifying the joint.
Need Help?
Need help confirming cartridge quantity, joint geometry, or substrate preparation for Sikaflex 15 LM sealant? Call (800) 220-1966 or email [email protected] with the joint dimensions and service conditions.







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