Abstract: A novel method and apparatus for supporting a vertical cylinder of wet cement surrounding a verticle pipe passing through a horizontal concrete slab in which one leg of an L-shaped piece is wrapped around the vertical pipe just below the slab and the other leg of the L-shaped piece is slit to form a series of slats which radiate horizontally around the pipe. A circular sheet of moisture resistant material having a hole in its center corresponding to the diameter of the pipe and slit from its center to its outer edge is slipped around the pipe just above the slats of the L-shaped piece, which is then pushed upwards on the pipe to press the sheet against the lower surface of the concrete slab. The piece and sheet are secured in position by a wire wrapped and twisted about the leg of the piece wrapped around the pipe. Wet cement can now be poured from above into the void between the pipe and the slab to be supported during its drying by the sheet and piece.