subfloor preperation for bathroom tile
 

I'm installing 12x12 tile on my bathroom floor. I removed the old vinyl and the 1/2in. partical board. The pb was glued in some random spots and some of the 3/4in ply came up with it. The floor joist are 10in doug/fir oin 16in centers. The bathroom is 6ft wide and 14ft long, with the joistsrunning lengthwise. MY plan was to use thin set and 1/4in hardi board before installing the tile. The 3/4in ply subflooring seems ok, but I have concerns about the parts that pulled up. I thought about putting 1/2 ply down first before the 1/4in hardi board or just use the 1/2in hardi board before installing the tile floor. Not sure which is the best way to go. Needing advise in Alaska...

add at least a layer of 1/2" underlay first then tile backer

Hi JA,

No way to tell you if the subfloor was damaged too much, you're the judge. Using 1/2" instead of 1/4" Hardie will only get you a little closer to the ceiling, it will not make your floor stronger. Best bet is to add an underlayment grade plywood, 3/8" min, 1/2" preferred, then the backer board and tiles. Or a membrane such as Ditra instead of Hardie.

Jaz

does your floor feel bouncy like the bath is in the middle of the floor joist span?

subfloor preperation for bathroom tile
 

The floor seems good and rigid. The tub is at the end of the room running width wise. So I am really not worried about that. The sink and toilet are on the left wall, so the main traffic and weight are in the center pathway to the tub, which has 3 joists on 16in centers. Thanks for your reply...

subfloor preperation for bathroom tile
 

Thanks you guys for the input... My gut feeling is to do just what you said, because I don't want any problems/cracking,etc. Anyway thanks a million!