HardieBacker Back-On Screws (100) is rated
Rated 3 out of
Don't self countersink
These have ridges to self-countersink into Hardiebacker board, so that the screw head is supposed to be level with the board surface. I found that if you apply sufficient torque for this the screw is usually overtightened and strips its hold in a timber batten. This is partly because the screws are quite short (32mm when I would use 38mm stainless). With less torque the head stands proud. I had to countersink the board with a countersink bit before tiling. Of course, the countersink bit (even carbide) only lasts for one set of boards.
Date published: 2015-09-12