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Discussion Starter · #1 ·
I am looking to see if it is acceptable to tile directly over a pre-existing plywood that has been previously used as a floor backerboard.
The bathroom floor construction is ¾” tongue and groove sub floor in decent shape and ½ plywood on top of that. Making the total floor 1 ¼” thick and quite solid.


The ply wood has a slight amount of what looks to be mastic / glue left over from the original tiles.
Can it tile directly on to this plywood, and if so how would this hold up. (at least compare to a standard cement board situation)

P.S. I also don’t want to remove the plywood backer board and replace it with concrete board because it has like 1000 nail holding it down.
Any suggestions are welcomed.:thumbsup:
 

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Tileguy
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Not knowing what type of tiles were there or what type of mastic, the safe thing is to install 3/8" or thicker underlayment plywood, then install a membrane such as Ditra or Noble's CIS. This saves you height problems. Ditra is 1/8" installed and CIS is thinner.

Although people have tiled direct on ply, (with some success even), the method is only possible on floors in dry rooms.

Jaz
 

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Just sold a tile repair job a few days ago that applies to this subject.

The original installer put the tile direct to plywood. Right outside the shower, the tiles started to come loose.

Over the years, every time someone got out of the shower with wet feet, a little water would seep through the grout and this delaminated the plywood to which the tile was bonded.

I like Jazman's suggestion about the Ditra or similar products... have long been a Schluter fan.

If the existing doubled-up decking is nice and solid with no noticeable deflection, I'd probably feel safe going right over that with the Ditra.
 

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Discussion Starter · #4 ·
Tiling over Wood Subfloor

This is sort of what i figured the combination of the slightly wet conditions in a bathroom and the limited success of tiling on plywood makes it best to remove of old 1/2" plywood subfloor.
I started messing with the hundreds or so nails holding the subfloor down and they seem to be removable.

Now, I plan in using basic 1/2" or 5/8" cement board over the ¾” tongue and groove sub floor and fiberglass tape & thinset the joints, and then thinset the 2"x2" (12"x12" sheet) glazed porcelain tile down over that. Making the floor about original height

I don't plan on water sealing the walls to the floors to the walls, (I expect water just not a ton)

Does this sound like a solid plan?
Would you recommend any different?
 
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