As a tilesetter, I often use Hardibacker as a floor underlayment. I use drywall screws to affix the underlayment and follow the dot patterns printed on the underlayment as I locate the screws. But without countersinking the screw holes, many of the screw heads end up above the surface of the underlayment, which can raise havoc with the tile level.
To solve the problem, I use a carbide 1/4-in. V-grooving bit chucked in my trim router to cut a countersink that accommodates the head of a drywall screw. It takes just a few seconds to follow the dots. And getting the screws started is easier with predrilled countersinking. I’ve done as many as 30 panels before a bit needs resharpening.
Will Hesch, Atascadero, CA
