How to Pour a Mud Shower Floor

Building a shower floor is a project that you should only undertake if you've had experience in carpentry and cement work. A shower floor, or pan, is a layer of sloped cement topped by a plastic liner, then more cement. The top layer is called deck mud and is formulated to provide a solid base on which to lay your tiles. This ensures than any water that gets through the tiles will be stopped in the cement bed and diverted to the drain.

Things You'll Need

• Tape measure
• 1/2-inch cement board for the shower floor
• 1/4-inch cement board for the shower walls
• Carpenter's glue
• 1-inch drywall screws
• Screw gun
• Razor knife
• Jigsaw
• Shower floor drain assembly
• Cement mesh screening
• Portland cement
• Sand
• Concrete trowel
• Wheelbarrow
• Shovel
• Level
• Plastic shower pan liner
• Staple gun
• Liner glue

Instructions

1. Cut a piece of 1/2-inch cement board for the floor of your framed-in shower, using your razor knife to score and snap the edges and your jigsaw to cut the hole for the drain in the center. Affix the board to the floor using carpenter's glue and drywall screws sunk every foot with your screw gun. Set the drain assembly in the drain hole.

2. Set your cement mesh on the floor, leaving a space for the drain. Mix your cement in the wheelbarrow with water according to the instructions on the cement packaging for a sloped shower base. Pour the cement over the mesh. Using your cement trowel, slope the cement so that it's about a 1/2-inch thick around the drain, and then rises by 1/4 inch for each foot toward the wall. If the wall is 3 feet from the drain, the cement that starts at 1/2-inch thick at the drain should climb by 3/4 inches over the span of 3 feet, to be 1 1/4 inches thick at the wall.

3. After the base layer of cement sets for a day, lay your plastic shower liner over it. The liner should go about 1 foot up the walls. Secure it with your staple gun. Cut a hole for the drain at the center. Use the liner glue to secure the liner around the drain. The liner should sit just below the small holes in the side of the drain assembly.

4. Hang 1/4-inch cement board from the walls, over the liner that's stapled partly up the sides on the bottom. Mix another batch of cement, this time following the alternate instructions for making deck mud. Sand will be added to the cement, and less water. The resulting cement will be thicker and drier.

5. Spread the deck mud down over the liner, making it about 1 1/4 inches thick around the drain. Keep it at that thickness to the wall, following the slope of the first layer of cement. Smooth it out with your cement trowel. Set the drain flange into the cement. Give it a day to set up, then tile over the top deck-mud layer.

Tips & Warnings

• Wear eye protection when using your jigsaw to cut your cement board.

References

• Building a Shower Pan