To install Hardie board for floor tiles, secure the plywood subfloor to the floor joists, sand down any ridges, sink screws and nails into the subfloor, precut the cement board to fit the floor, apply thin-set mortar to the subfloor, and then install the boards. Cover the seams with tape and thin-set mortar.
- Prepare the subfloor
If the plywood subfloor squeaks, secure it to the floor joists with screws. Check the subfloor for any bumps or ridges. Sink all screws and nails into the subfloor, and sand down any ridges.
- Trim the backerboard
Measure the cement board, also known as backerboard, to fit the floor. Score the back side of the board, and snap the piece of backerboard to size.
- Install the cement board
Mix a batch of thin-set mortar. With the flat edge of a trowel, smooth on the mortar, and then comb it with the notched edge. Press the backerboard into the mortar, and secure it with 1 1/4-inch cement board screws every 4 inches.
- Cover the seams
Before installing the tile, cover the seams with cement board tape. With a putty knife, spread thin-set mortar over the tape, and smooth it out to remove any bumps or ridges.
- Install the tiles
Working in small sections, smooth thin-set mortar over the backerboard, and lay the tiles with spacers.