Install a Backerboard Around a Toilet Flange
Installing a concrete backerboard around a toilet flange can be a weekend project that can be completed with the right tools and enough patience.
Step 1 - Cut the Backerboard
Cut a shape out of the backerboard to fit the space around the toilet flange.
Step 2 - Measure and Draw
Using a tape measure and pencil, draw the placement of the flange on the backerboard. Draw a circle between the measurements.
Step 3 - Score the Board
Score the backerboard with a utility knife. Deeply score a pie-shaped pattern inside the circle drawn on the backerboard.
Step 4 - Knock Out the Wedges
Gently knock out the wedges of the scored backerboard. Take care not to break or damage the edges of the circle. Discard the wedges. Place the backerboard around the toilet flange to test the fit. Using the pencil, mark any place that needs to be further cut out or made wider. Pull the backerboard up and use a drywall shaver to shave off areas of the backerboard that need to be cut down.
Step 5 - Attach the Board to the Subfloor
Use cement backerboard screws to attach the backerboard to the subfloor. Place at least 4 screws around the flange 1.5-inches from the edge of the flange hole.