Tile experts!

[Cameramonkey]

Long story short 10 years ago we laid tile in the bathroom and didnt lay backer board down. 3 guesses what Im dealing with now?

So the wife wants that cracked crap replaced. Here is my question. Do I need 1/4" or 1/2" backer? its an 8'x5' bath, built in 1981. We are looking at 13 or 16" square tiles.

The only gotcha is around the toilet I had to build a box frame in the floor joists and replace a 2x2 square of rotted subfloor around the toilet flange. I used outdoor rated plywood and its not exactly identical in height to the subfloor. (1/16"? Diff)

So what sez the flooring experts? Do I need do anything about the difference around the toilet? Or will the backer board be enough?

 

[Informed Decision]

Here goes my two cents worth.. Probably the Hardibacker ( my recommendation over Durrock)can take care of the difference in heights but I would feather it out with a belt sander. Especially if the area is going to be an area of weight support transfer such as standing and sitting. 1/4" normally will work for flooring, but depending on how level you are may require going to the thicker size. Minor difference in level can be taken out with the mortar.

 

[Cameramonkey]

Thx. another user PMed me somem suggestions, and I'll be replacing that treated with standard 3/4 subfloor to level it out and correct any offgassing issues. (Now I realize that after boxing off that rotten section surrounding the flange, if it WERE to get icky and rot again I can simply replace it; I dont need to worry about it NOT rotting. (and besides, I'm a decent plumber that knows how wax rings work and how to install a toilet properly to negate the issue)

And I was going for the Hardibacker. That adds a whopping $8 I think to the job.