When building a large or oddly shaped shower, building your own shower tray may be your best option. A shower tray or pan is the bottom or floor of the shower. The largest prefabricated shower tray that is not custom-made is 72 inches by 72 inches. Making a very large shower tray gives you the freedom to make it any shape or size you desire. The large tray will take two to three days to create without adding tile.
Remove all the debris from the area where the shower will be placed, and sweep the floor to remove all the dust.
Install the shower drain assembly and make sure it stands 2 inches above the existing floor. Place duct tape over the holes in the drain.
Measure the area where the shower tray will be placed and cut the 2-by-4-inch boards to frame the outside of the shower tray. The tray is completely surrounded by 2-by-4-inch boards. Measure the front of the shower and cut a 2-by-6-inch board to run across the front. The 2-by-6-inch board will be the curb, or front, of the shower --- the place you step into.
Create the frame with the 2-by-4-inch boards and attach them together with wood screws. Lay the 2-by-6-inch board across the front and attach this to the 2-by-4-inch frame with wood screws.
Lay out the rubber membrane and use the utility knife to cut it to the dimensions of the shower plus 6 inches on all sides. Measure the drain and cut a hole in the membrane so the membrane slides over the drain. Stretch the membrane over the shower floor and pull it tight. Attach the membrane to the shower frame using the screws. Attach one side first, then stretch it out and remove all the wrinkles; then attach the other sides.
Measure the roofing paper to fit in the bottom of the shower and cut a hole in the centre for the drain. Place the paper in the shower and flatten it out.
Place a 1-inch layer of concrete in the shower and slope the concrete slightly toward the drain. The concrete should be 1 inch thick around the edges, and 1/4 inch around the drain. Use the trowel to smooth out the concrete and create the angle. The level will show you where the concrete starts to angle downward. Let the concrete dry.
Cut the chicken wire with wire cutters to fit in the shower tray. Remove a section of wire around the drain and slide the chicken wire into the shower tray.
Pour another 2 inches of concrete into the shower and smooth it out so that it angles downward to the drain. The drain will sit level with the top layer of concrete. Cover the frame and the 2-by-6-inch curb with a thin layer of concrete.