Backup Rods The Backer Rod & Backup Rod offered by us are flexible, Readily compressible and have long for a variety of applications. Applications: Expansion/contraction jointsConstruction joints/coping jointsWindow and door frames.Pressure relief joints.Separation/isolation joints Features Compatible with polysulphide and silicone sealants.Prevents seepage of water and moistureEase of installation.Provides excellent resilience to the groove.Allows joint movement