Expansion joint sealing or caulking is needed for many reasons. The most common applications comes from a repair. In most cases when a lift is performed the expansion joints have become exposed and need to be sealed to prevent any future damage. Watershed will seep into the gaps and either flush out material underneath the concrete and create a void, or freeze and crack leading to expensive repairs and replacements. The flexible polyurethane caulking specifically designed for masonry applications allows the slabs to move and shift with out comprimising the seal.