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Document record
This two-page technical data sheet covers KF-460 KoolFlex silicone mastic, a high solids, moisture-cure 100% silicone mastic. The sheet lists its use for sealing and repairing roofs, flashings, walls, masonry, and metal roof seams and fasteners. It is marked revised January 2025 and is designed for trowel or brush application on vertical or horizontal surfaces, with a build up to 1/4 inch.
Adhesion is listed on concrete, masonry, vinyl, fiber cement, polyurethane foam, EPDM, aged acrylic coatings, granular cap sheet, wood, metals and Kynar. The sheet says the mastic may be applied to wet and underwater surfaces, and that a primer may be needed. Repairs use a 1/8 to 1/4 inch layer, with edges feathered 2 to 4 inches beyond cracks. The application rate is 24 square feet at 1/16 inch, or 12 square feet at 1/8 inch.
Application temperature is 35 to 120 degrees F. The mastic is tack-free in 1 to 3 hours and fully cured in 24 hours, with cure affected by weather, humidity and temperature. Listed properties are tear resistance of 82 lbs/in, Shore A hardness of 70, VOC of 50 g/L, and service temperature of 15 to 180 degrees F. Packaging is tote, drum, 5 and 1 gallon. The sheet says the product is not recommended for interior use or for application below 35 degrees F.
Material changes / notes
Use this component sheet with the complete roof-system specification. Follow the preparation, application and cure instructions for the selected substrate and coating layers.