To install a backer board for tile, lay the boards over the subfloor, cut obstruction points, spread thinset mortar over the subfloor, and screw the boards to the floor. It takes approximately one hour to complete 1 square foot of this project.
Start by gathering necessary material and tools, including a cement backer board, thinset mortar, a contractor's pencil, a circular saw and safety goggles. Add a notched trowel, a cordless drill, cement board screws, a contractor's paper and fiberglass seam tape. Once all the material and tools are in place, spread out the boards over the subfloor without affixing. Using the carpenter's pencil, draw cut lines over the board. Draw any obstruction points on the contractor's paper, cut them out from the paper, lay the cutouts over the board, and trace them with the pencil.
Using the circular saw, cut partial boards to facilitate installation of the board around the obstruction points. Be sure to protect your eyes with the safety goggles while cutting. Spread the thinset mortar over the installation surface, apply the notched trowel to comb the mortar, and follow up by laying the boards over the mortar so the boards are 1/8 to 1/4 inch apart. Secure the boards by screwing their edges using a cordless drill, taking care to ensure that the screws heads sink slightly into the board. Finally, apply the fiberglass tape to the seams, fill in the mortar, and allow the floor to dry.