Watertite, 12 OZ, Polyurethane Sealant, Permanently Flexible Watertite Polyurethane Sealant Is Suitable For Bonding, Sealing In Expansion Joints As Well As Waterproofing Concrete & Other Masonry Materials. Permanently Flexible Watertite Polyurethane Sealant Is Suitable For Bonding, Sealing In Expansion Joints As Well As Waterproofing Concrete & Other Masonry Materials. Flexible joint filler Waterproofs as it seals