Backer rods are used as a “backing” material to fill a void, joint, or crack in residential and commercial applications. The primary purpose of backer rods is to: Control the sealant thickness and amount needed to fill the joint. Force the sealant to the sidewalls to ensure contact and proper adhesion.

What does a backer rod do?

What is a backer rod and what does it do? Backer rods are usually round, flexible lengths of foam that are used as a “backing” in joints or cracks to help control the amount of sealant/caulking used and create a back stop. Many sizes/diameters are available for optimal fitting to the size of the joint being sealed.

Do I need to use backer rod?

Standard backer rod is recommended for glazing installations, window and door applications, expansion joints, log construction, pavement joints or repairs and precast concrete joints and copings. It's compatible with most cold-applied sealants.