Abstract: An arrangement for preventing seepage through a wall from running onto the poured concrete floor of a basement or the like, comprises a vertical channel member positioned between the wall and the floor and having spaced flat surfaces spaced from the wall, and a water impermeable facing strip abutting the flat surfaces which are spaced from the wall and against which the concrete floor is poured. A horizontal channel member has spaced flat surfaces abutting a footing which supports the walls, and alternate spaced flat surfaces spaced from the footing. The concrete floor is poured directly on the horizontal channel member.