Olympic’s Foamlite Backer Rod is polystyrene rope that is a subfiller for expansion joints and crack repair. It is for use underneath as a base for Thermolastic and Permaseal fillers.
Prevents the need to completely fill the gap as it provides a surface for the filler to harden on top of. Significantly reduces the amount of filler required to fill gaps.
Since the foam does contract, it is suggested that you purchase a diameter slightly larger than your crack to ensure a tight seal.
