Waterstop steel plate, also known as steel waterstop, waterproof steel plate, is typically made by straightening and bending coiled steel strips. After the foundation is laid, waterproof steel plates or waterstops are required between construction joints for waterproofing treatment. Generally, a waterproof steel plate measures 3 meters in length and is used at construction joints and expansion joints on the site, welded into the construction joints to provide waterproofing.

In the base or basement with box-type construction, the concrete for the floor and exterior wall panels, as well as the roof, is cast separately. When pouring the concrete for the wall panels again, a construction cold joint is formed. If the location of this joint is below the water table, it is prone to leakage. Technical treatment of this joint is required, and there are various methods, with the most common being the installation of a water stop steel plate.