What is a waterstop or waterbar?

A waterstop (or waterbar) is a pre-formed strip embedded into concrete joints (construction or expansion joints) to act as a physical barrier to water. They can be made of PVC, rubber, or hydrophilic materials (which swell when wet). In Type B waterproofing, waterstops are essential because while the concrete may be waterproof, the joints between pours are not. We also retrofit waterstops using mastic or resin injection for existing leaks.