6mm Backer Rod
Closed cell joint backing foam also known as backer rod or polycord, is a flexible polyethylene cord. It allows the volume of sealant or mastic used to be minimized and reduce overall cost as well as allowing the user to obtain the optimum sealant shape or design, which prevents joint failure. Foam backer rod is chemically and physically neutral, which is non-absorbent and will not rot. It can also be incorporated into side insulation and expansion joints preventing heat loss and provide acoustic properties.