Hi,
Not too long ago I posted a question about tile failure. The area experiencing a lot of tile breakage (about 16 out of 60 tiles) is in the high traffic area of a kitchen – in front of the sink, refrigerator, etc…
The floor is framed with 8″ steel joists (c shaped), 16 o.c. and has an OSB subfloor. I was able to watch the floor, from the basement, as the customer walked through the kitchen and noticed a lot of deflection in the subfloor. There were also subfloor joints that did not break on a joist. So I decided to add an additional joist in each bay of the failure area to reduce the span of the osb as well as catch some of the floating joists. (All joists were fit snug with liquid nails to the subfloor and secured). This has solved the deflection problem.
So I went on to phase 2 and started demoing the broken tiles. I found that the floor has an additional layer of non-engineered plywood with the tile installed directly over it. All tiles seem to have good thinset coverage on the backside but none are putting up any kind of a fight. Also found old water stains and mold from a leak under the tiles in front of the dishwasher.
My question: How should I go about installing the replacements? I am not comfortable with going right back over the plywood if that is the issue as well. Usually I use kerdi. I couldn’t add that on top of the existing plywood because then my tile would be too high…..should I demo out the secondary ply subfloor and install kerdi as deflection really shouldn’t be an issue any more even with kerdi over osb? Is there a particular thinset you tile setters trust more directly over plywood? Any feedback would be appreciated, also if you get any other ideas from my clues above about other possible problems/ I would love to hear them.
Thanks
Replies
How thick is the "non
How thick is the "non engineered" plywood that's directly under the tile? I would be looking to remove that and replace with CBU of same or lesser thickness.
not sure about the thickness of the plywood underlayment. Would it be crazy to cut it out in the sections i am repairing and put down a better underlayment in just those spots? Just want to make sure its done right.
>>>The customer is really not
>>>The customer is really not interested in a total tear up of the kitchen.
Too bad, because it sounds like that would be the best solution by far. If I were them I'd save my pennies for another year, then do it right by thickening the subfloor.
The trouble may also be due to inferior tiles. I would not guarantee this work but you could try putting the tile down on a flat bed of modified thinset instead of notched trowel bed. If the replacement tiles are new, then they may stay unbroken. Seal the repair area so the wood subfloor does not dry the thinset too quick. Hope it helps.