How to Build a Tile Shower Base on Concrete Floors

Insert the bottom flange for the drain pipe assembly into the drain hole in the concrete floor.

Prepare a batch of mortar, following the instructions on the packaging.

Pour the mortar onto the concrete inside the shower stall, placing more mortar around the edges of the stall than around the drain hole.

Drag a 2-by-4 board across the surface of the mortar to smooth it. Slope the surface of the mortar down away from the sides of the stall so the mortar is about 1 1/2 inches thicker around the perimeter of the stall than around the drain hole. Allow the mortar to set for 4 to 5 days.

Measure the midpoint of each wall of the shower, and snap a chalk line between the opposing walls to divide the shower floor into four equal quadrants.

Prepare a batch of thinset, following the manufacturer's instructions.

Cover a 1-square-foot space in the corner of one quadrant of the shower floor with the thinset. Apply the thinset with the smooth edge of a notched trowel, and then make a pass over the thinset with the notched edge to create grooves in the thinset.

Begin laying the tiles in the thinset in the center of the shower floor, working toward the side wall. Lay tile spacers between the tiles. Add thinset to the concrete as needed until you reach the wall. Stop laying tile when you cannot fit a full tile.

Lay tile in the same quadrant, but work toward the front wall, laying it perpendicular to the first row of tiles.

Lay a second row of tiles parallel to the first row, and then add a second perpendicular row. Continue laying tiles in this alternating fashion until the quadrant is complete.

Lay tile over the other three quadrants, using the same technique. When tiling around the drain hole, lay the tiles into position around the drain, and trace the outline of the drain hole onto the tiles. Cut the tiles with a wet saw along the line.

Cut tiles to fit around the perimeter of the shower base, and set them into the base with mortar, if needed. Allow the mortar to set for about an hour.

Scrape away with a putty knife any thinset that seeped between the tiles, and remove the tile spacers with needle-nose pliers.

Prepare a batch of grout, following the manufacturer's instructions.

Scoop the grout onto the tiles with a grout float. Apply the grout by making several passes diagonally over the tiles with the grout float to completely fill the joints. Allow the grout to set for about 20 minutes.

Wipe down the tiles on the shower base with a damp sponge to remove the grout from the surface. Rinse the sponge frequently as you do this, and then allow the grout to set for about 45 minutes.

Wipe down the tiles with paper towels to remove the hazy film from the surface.