HBR® is a closed-cell polyethylene foam backer rod used in concrete construction. HBR acts as a barrier, limits the depth of cold-applied sealant required and prevents excessive sealant use. It helps cold-applied sealants assume the optimum hour glass shape to prolong the sealant service life. It is commonly used in applications such as expansion and contraction joints, curtain walls, construction partitions, parking decks and bridge construction. HBR is an inert material, and therefore, it is physically and chemically compatible with virtually all known cold-applied sealants including self-leveling types. Sealant compatibility should be confirmed by the sealant manufacturer.