Waterstop steel plate, also known as steel waterstop belt or waterproof steel plate, is generally made by straightening and bending coil steel strips. After the foundation is laid, waterproof steel plates or waterstop belts are required between construction joints for waterproofing. Typically, a waterproof steel plate measures 3 meters in length and is used at construction joints and expansion joints on-site, where it is welded to the construction joints to provide waterproofing.

In the base or basement of the container, the concrete for the floor and exterior wall panels, and the roof, is cast separately. When pouring the concrete for the wall panels again, there is a construction cold joint. If this joint is below the groundwater level, it is prone to leakage. Technical treatment is required for this joint, with various methods available, one common approach being to install a waterstop steel plate.