How to Make a Walk-In Shower Pan Without a Threshold

Measure the area around a floor drain to at least a 60-inch width and at least a 30-inch depth from the wall. Mark this area with masking tape, and remove the floor inside the masking tape to a depth of three inches, using a circular saw to remove the joists and floorboards in a wood floor or a sledge hammer to break up a concrete floor and then chisel and hammer to carve out the 3-inch trench. Remove all of the concrete bits from the trench.

Reinforce a wood floor by measuring the distance between the floor joists and cutting 2-by-4 boards down to this length. Cut enough boards that you can place one every six inches between the joists. Place one of the boards you cut alongside a joist in the open area of the floor and trim the board down lengthwise, if necessary, to make it the same height as the joist. Trim all of the other cut boards to this height.

Put the boards in place between the floor joists every six inches. Nail the boards into place with two nails through the joists and into the boards at each end. Cut a plywood panel to the size of the opening in the floor, place the panel on top of the joists and nail it to the joists every three inches.

Add the amount of water recommended on the concrete mix packaging to concrete mix. Mix the concrete mix and water with a drill with a mixing bit.

Dump part of the concrete mixture into the opening in the floor. Spread the mix with a trowel until the concrete in the area of the floor closest to the drain is about an inch high and the floor slopes up toward the edges of the hole. Let the concrete dry.