Water seal plate. In the box foundation or basement, bottom plate and outer wall panel, the concrete of the roof is poured separately, the next time the concrete of the wall panel is poured, there is a construction cold joint, when the joint is located below the groundwater level, it is easy to produce water seepage. In this way, it is necessary to carry out technical treatment of this joint, and there are many ways to deal with it, among which the more popular method is to set the sealing steel plate.