I've already got the cement board down, taking it back up would mean messing with the toilet flange, which means plumbing, and that sucks. Plywood was in pretty good condition. Thanks in advance!
Just use a bunch of screws to hold the cement board in place. If you do this it will be just fine.
Ya, you should make sure that you have enough screws in it so it doesnt shift. thats the main purpose of thinset between the cementboard and subfloor. If your using hardibacker it shows you were every screw should go about 25 screws in each. You also should thinset the joints, just like drywall.
If you don't apply mortar, the tile will shift around, come up, etc. It's best to go ahead and do it right when you are initially laying it therefore saving yourself a costlier repair. Good luck.
