Cutting Backerboard

One of the last steps in preparing a wood floor, countertop, or wall surface for tiling is to install backerboard. Concrete backerboard creates a solid, durable substrate for tile work to be set on top of. It’s affordable, easy to cut, and helps make these installations structurally sound and long lasting. Backerboard installation is a four-step process: Measure and cut the board to size, bond it to the surface, fasten it with nails or screws, and then tape the joints. Start by measuring the area that’ll be tiled and calculate the number of sheets of backerboard to buy. Then figure the size and shape of each piece you’ll need to cut.

You can cut backerboard by hand using a scoring tool or with the use of power tools. If you cut by hand, mark your cut and use a scoring tool along a straightedge to score the sheet 1. Match up the backerboard’s scored edge with one edge of the straightedge and apply pressure downward, breaking off the scored board 2. For more complicated cuts, like L-shaped cuts around a cabinet or a circle for a toilet flange 3 or heating vent, use an angle grinder or jigsaw. Because these tools generate lots of dust, cut outdoors whenever possible and definitely wear a dust mask, goggles, and hearing protectors. Test-fit your piece 4 and trim with tile nippers as necessary 5. Always do this before spreading thinset to avoid a real mess.

	1. Hold the straightedge securely and drag a carbide-tipped scoring tool over the backerboard, to score it along the line of cut.
	2. Position the backerboard with its scored line along the edge of a level or straightedge and apply downward pressure until it snaps.
	3. Use a compass or round object to mark out circular cutouts for fixtures.
	4. Dry-fit the cut backerboard piece and mark any areas that need to be trimmed.
	5. Trim backerboard with tile nippers and recheck the fit.

Excerpted from Tiling Complete, 2nd Edition by Robin Nicholas and Michael Schweit.

Available in the Taunton Store and at Amazon.com.