How to Build a Seat in a Shower Pan

Draw a pencil outline on the shower pan floor to indicate the outer parameters of your shower seat. The easiest method is to simply run two blocks lengthwise across the face of the bench, and two blocks deep, meaning that four blocks are placed so that they run lengthwise into the corner with the width of them forming the front to back of the bench.

Put down at least 3/4 inch of mud on the floor of the shower pan within your outline. Lay your blocks down on top of this mud bed with at least a 1/2-inch gap between the blocks. Use a mason trowel to put more mud in between the blocks. Tap them together with a rubber mallet, and use a level to make sure they are level in the base of concrete mud.

Add another 3/4 inch of concrete mix on top of the first layer of blocks and stack another row of blocks on top of the first. Repeat this method until your bench is as high as you want it, layering between each block and row with more concrete mud. Level each row with the level, tamping them down into the mud beneath.

Create the top of the seat. Put 1 1/2 inch of concrete mix along the back portion of the top of the concrete seat, an inch of mud in the center sections of the seat and about 3/4 inch of mud along the front section.

Cut a piece of concrete board to fit the top of your seat, using the utility knife to score the face of the board. Snap it across this scored line to break the piece off. Place the piece of board on top of the concrete. Use the level to tamp the board down into the concrete so that it is level across the back, level across the front, but sloped from back to front roughly a quarter of an inch so water drains when the shower is on.

Scrape away all excess mud and let the seat dry. Tile over it with natural stone or ceramic tile to finish the installation.