drywall screws spaced every 6 in. Use 1/4-in. thick cement board instead of the usual 1/2-in. cement boards that some in sheets. That’ll keep the floor thickness to a minimum.

Step 9: Use a carton knife to score and break a new piece of cement board to fit into the newly created void. Step 10: Attach the new board to the studs with corrosion resistant screws.

Most brands of concrete backer-board consist of a fibrous reinforcement cement composition molded ... fastened to the wall studs with galvanized screws or rustproof concrete backer-board screws.