Then you want to install screws into the concrete board in each of the holes.
How to tile on plywood wall.
Spread the mastic over a 3 square foot section of your installation area using a notched trowel onto the wall.
Sand with a medium grit sandpaper to create a uniform surface that s not too smooth.
Seal the walls with a skim coat and let it dry thoroughly.
For wall installations plywood is overkill beneath the concrete or fiber board which is designed in five eighths inch material for wall settings.
The preferred method for tile installations is to use a sheet of underlayment.
When creating a grid pattern start at the center where the lines intersect.
Plywood is not dimensionally stable it can shrink swell and otherwise move around no matter how many screws are holding it in place.
Use your drill to make this job simpler.
Shrinking and swelling will crack the grout can pop off tiles etc.
You want the tile adhesive to have something to grab onto.
Use intervening layers of two sheets of plywood.
Use thinset with a higher latex content thinset is the wet base that you first trowel on the plywood to make the tile stick.
Center your tile in the bathroom.
If possible you should always use concrete board underlayments rather than plywood.
Thoroughly vacuum the area and give the wall a once over with a damp sponge or cleaning cloth.
While tile can be laid on plywood do not install tile directly onto the plywood subfloor itself.
There are tiling mats you can cover the plywood with decoupling mats such as ditra you then tile right over that.
To do so measure to the center point of each wall with your tape measure.
Step 4 center.