Polyurethane sealants are a one-part, moisture-curing, gun-grade sealant. They are durable, flexible and offer excellent performance in moving joints. Polyurethane sealants don`t require a primer on most construction materials. Polyurethane sealants are an excellent general purpose sealant designed for use in precast, masonry, window frame perimeters and similar types of construction joints. They are also suitable for continual immersion in water.