Filler Rope, Pre-Caulking, 50 ft Lg, Gray, Poly Foam, Reel

Sashco’s pre-caulking filler rope (also called “backer rod”) makes professional joints that last. It helps fill in and insulate large caulk joints, allowing the caulk to absorb more movement. The caulk adheres to the sides of the joint, but not to the filler rope, so the caulk can stretch and compress without tearing or pulling away. It is made of closed cell poly foamt, with a minimum R value of 2.5 in, Available in several sizes and lengths.