Laying HardiBacker to Floors

Lay a sheet of HardiBacker on the floor in one corner of the room, so it runs along two adjacent walls. Trace around the border of the board onto the floor with a pencil. Remove the HardiBacker.

Spread thinset mortar over the whole marked-out area with a notched trowel.

Set the HardiBacker board back in place. Step over board sections rather than on them to allow the mortar under each board to set and dry.

Shoot galvanized flooring screws at each dot on the surface of the board, covering the whole board in a grid pattern of screws. Sink the heads of the screws completely.

Lay the next sheet of HardiBacker at the end of the first sheet in the same manner as before, spreading mortar under it and then screwing it down. Repeat the process, arranging the boards end-to-end along one side of the room.

Cut the last board in the course by scoring a line across it with a razor knife and bending it until it breaks at the line.

Lay the next course of HardiBacker boards starting at the opposite end as you did for the previous row, so the seams of the boards don’t line up between rows.

Press mesh drywall tape over the seams between the boards. Use a drywall knife to spread thinset mortar over the tape, getting it smooth and flat. Let the mortar set 12 hours before laying tile.