XPERT Polyseal is a two-part, self-leveling or gun-grade, XPERT Polysulfide Sealant, which effectively seals joints that are subject to structural or thermal movement, as well as non-moving joints, against infiltration of water and dirt. It will effectively prevent water from entering the sealed joints and thereby eliminate erosion of the soil underneath the slabs, particularly areas which are exposed to water frequently, such as swimming pool decks and around planters. All coping joints and deck joints should be sealed. In adobe soil areas, unsealed joints may cause swelling of the soil and subsequent buckling and cracking of the concrete slab.