A closed-cell foam backing rod is used to partially fill a concrete joint to create a backing for joint sealant. 

Backer rod may be used in floor and paving joints and in between precast panels. 

Choose a size that is slightly larger than your joint width so the foam is securely held in the joint. 

Installation is easy, simply stretch the back rod slightly, place it into the joint, and release. 

Backer rod foam is supplied in handy length rolls for all types of projects - Size is 50mm x 2m