I am a beginner researching(you tube) on how to install ceramic tiles on my kitchen floor(plywood subfloor). I've started laying my 1/4" HardieBacker underlayment, but have been told by a contractor that it isn't necessary to apply thinset under the underlayment. Should I stop and apply the thinset or keep going ?
Rhonda Garner ~ Lithonia, Georgia
Rhonda, the reason your contractor may have told you not to use an underlying layer of thinset is because some contractors don't believe it is necessary, or they incorrectly opt to use an adhesive instead. The reality is that the installation instructions supplied by the manufacturers of HardiBacker do require you to apply a supporting bed of mortar or modified thinset to the subfloor underneath the 1/4" sheets. When installing HardieBacker sheets remember to also stagger them(running bond pattern) so that no 4 corners touch and so that there are gaps around all 4 sides of the each board (approx. 1/8-inch wide). Using thinset mortar and special tape to seal the seams between the sheets is also necessary.
Just to make sure that you start your project on the right path, why don't you review these installation instructions found on Hardie's website. Good luck!