Measure and mark the cut line with a pencil or marker
Place the backer board on a stable, flat surface
Use a carbide-tipped scoring knife to score the line several times
Snap the board along the scored line
Use a utility knife for small trims or light cuts
Use a jigsaw with a carbide or diamond blade for curved cuts
Use a circular saw with a fiber-cement blade for straight cuts
Use a grinder with a diamond blade for notches or detailed cuts
Cut outdoors or in a well-ventilated area
Wear a dust mask or respirator, safety glasses, and gloves
Support the board fully to prevent cracking
Smooth rough edges with a rasp or sandpaper
Clean up dust with a vacuum or damp cloth