ChimneyRx Masonry Fireplace Crack & Joint Sealant - 1 Pint Brushable elastomeric sealant for mortar joints used to repair exterior cracks in mortar on chimneys, brick walls and between concrete or stone masonry units The product seals larger cracks and other defects that cannot be corrected with water repellents alone Crack & Joint Sealant seals crack up to 1/8" wide on brick faces and at mortar and brick joint interfaces to provide waterproof protection It dries to a clear, translucent, milky film When applied to a properly prepared wall or chimney surface, Crack & Joint Sealant can solve tough leak problems without the expense of truck pointing or surface grouting