How to Correct the Slope in a Shower Pan

Remove the flooring material from the shower pan. If the shower has a fiberglass liner that includes a floor, unscrew or unclip the brackets that hold the unit in place on the wall. If the shower has a tile, stone or slate floor, chip away at the grout between the tiles with a screwdriver and hammer until you remove all grout from between the tiles, and then pry the tiles up one by one.

Measure each side of the shower pan that doesn't sit next to a permanent wall. Cut a wood board of the proper length for each of these sides. Place the boards on the floor next to the shower pan right against the shower pan edge, and place a brick at each end of each board on the outside of the shower pan to hold the boards in place, to create a temporary wood wall on that side of the shower pan.

Remove any adhesive left on the shower pan floor by scrubbing the surface with steel wool. Use a wet rag to clean up the debris left on the surface.

Mix portland cement with sand, using approximately three times as much sand as cement, in a bucket. Add water to the mixture, using a drill with a mixer, until the ingredients hold together without coming apart in clumps.

Spread the portland cement mix over the surface of the shower pan with a trowel so that the cement sits highest at the outside edges where it touches the permanent walls and temporary wood walls that you put into place and lowest at the area around the drain. Make the mixture sit at least 1/4 inch lower at the drain than at the perimeter, though the more slope you can give the shower pan floor while still maintaining a relatively flat surface to stand on, the better the results.

Set a level on top of the freshly spread portland cement mixture. Ensure that the bubble inside the level moves fully out of the marked center area of the level, which indicates enough slope. Continue spreading the cement mixture until the bubble moves fully out of the center area when laid on the shower pan floor.

Allow the cement mixture to cure on the floor for approximately 72 hours. Remove the bricks from the floor, and pull the temporary wood walls away from the shower pan. Once the shower pan has fully dried, re-lay the flooring that you removed, or put the fiberglass shower liner back into place.