Remove plywood subfloor before tileing

[Eric921]

I am going to tile a guest bathroom. I have removed the linoleum and all adhesive. There is a 1/4 plywood layer over the original subfloor. The floor is dry and clean. Do I need to remove the plywood subfloor before installing the backer board and tile?

[kurt]

Maybe.

How are the elevations going to lay out? IOW, after you install the backer board, will the new tile floor meet existing floor, or will there be lippage or trippers?

[mjr6550]

If the 1/4 plywood has any give to it at any area I would remove it. Anything not glued down is suspect. I generally like to get down to the original sub-flooring anyway.

[kurt]

I agree. Always clean as much of the old stuff out as possible. Leaving anything is setting up for failure.

[Garry Sorrells]

Plus add the material for bedding the backer board into the equation. I would probably remove the 1/4 board for a better job.

[kurt]

I've become a fan of Ditra. I've really gone over to the other side and don't even think about cement board anymore.

In which case, you'd be taking out the 1/4" underlayment and placing new....something or other as a subfloor for the Ditra.