Attach the Backer Board
Fasten the backer board to the floor using proper nails or screws, as recommended by the manufacturer, every 8" around the perimeter and all supporting the studs. Keep fasteners between 3/8" and 3/4" from sheet edges and 2" in from sheet corners. Make sure that the nail or screw heads are not sticking up above the board surface.
Note: In some cases, you can attach the backer board joints using 2" wide glass fiber mesh cementitious alkali-resistant backer unit reinforcing tape (see product instructions – usually needed for wide areas). The tape will help disperse any movement of the boards and decrease the probability of popping or cracking tiles along the seams.