5/8" X 20' CAULK BACKER ROD

Foam Caulk Backer Rod is a closed-cell polyethylene foam rod designed to improve the performance and longevity of caulking and sealant applications around doors, windows, expansion joints, and other construction gaps. Measuring 5/8 inch in diameter and 20 feet in length, this flexible backer rod provides a reliable backing material that helps create properly shaped sealant joints while reducing the amount of caulk required for each
project.

  Engineered to compress easily, the foam rod fits securely into joints and irregular gaps before sealant is applied, helping control the depth of the caulk bead and promoting better adhesion to the sides of the joint. This two-point adhesion allows the sealant to expand and contract more effectively as building materials naturally move with changes in temperature and humidity, helping reduce the risk of cracking, splitting, or premature sealant failure. It is commonly used around window and door frames, concrete joints, siding, log homes, and other applications where durable weather sealing is required.

Manufactured from durable closed-cell foam, the backer rod resists moisture absorption and provides excellent flexibility for installation in both straight and irregular openings. It can be easily compressed to accommodate slightly smaller joints while maintaining enough resilience to stay securely in place during sealant application. The material is compatible with most common construction sealants, including silicone, polyurethane, acrylic latex, and other elastomeric caulks, making it a versatile choice for residential and commercial projects.

  Ideal for contractors, builders, and homeowners, Foam Caulk Backer Rod helps create stronger, longer-lasting sealant joints while improving application consistency and reducing material waste. Its professional-grade construction, easy installation, and ability to enhance the performance of caulking systems make it an essential accessory for weatherproofing, insulation, and expansion joint applications in both new construction and repair projects.