So, let's skip the "how" and get to the mistake. I used VersaBond (A118.1, A118.4, A118.11) "Polymer modified" "fast setting" for the entire project. It wasn't till today that I was looking up dry times, when I realized my mistake and that "Polymer Modified" is the same thing as "latex modified" which is great for the bottom layer, but not for the top.

I used 16x16 tiles over about 1+1/4" wood subfloor. So, my question is likely obvious and could be summarized as "what would you do" -- after you're done throwing a few tools thru windows and crying in your beer.

Do I rip it up? If so, just the tiles or Ditra as well? Or, do I simply have to wait longer. In the instructions it says it may take 14 - 60 days for latex modified to cure. I'm assuming in my case if I'm to wait, I would wait the whole 60 days since I used 16x16 tiles. Or, is waiting a complete waste of time and I'm just delaying the inevitable? I am going on a 14 day vacation in a week. So, staying off it at least for that time would not be a huge inconvenience. Also, it's fairly hot and dry here. Around 85 - 90 in the day and 65 at night and I could keep heat and/or air moving on the tiles if that helps. The tile is interior, climate controlled to 75.

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    I wish I could give you the right answer, but I don't agree with Ditra on using unmodified and I still don't but I cut the modified with a 50/50 mix of unmodified. The part that gets me is that thinset cures by chemical reaction not evaporation the same as concrete so I thought. I never researched, but I do know concrete cures and gets hard underwater. I have poured it, pulled the forms etc all in the water. It got hard. So I don't understand why, since thinset is along the same lines, I know they will not honor a warranty should it fail, but if it don't fail, why sweat it?
    – Jack
    Commented Sep 29, 2015 at 2:34
  • My understanding was that the latex compound had to evaporate to dry. How else could you buy pre-mixed latex modified and have it still be wet? But, maybe I misunderstood. In any case, I'm coming to the conclusion that as you said, if it don't fail, why sweat it? I'm going to leave it for 14 days before walking on it. Otherwise, I'm not going to worry about it. And, after posting on the JohnBridge forums (tile forums), I'm being told by other experts that I'm way over cautious anyway and should have no issues.
    – maplemale
    Commented Sep 29, 2015 at 15:02
  • I have looked over the forums too, looking for details on thinset setting up by evaporation or chemical reaction. I will not use the ready mixed stuff. Nor have I seen it. I have seen ready mixed grout though, I would not use it either. I am sure the stuff in either type has a shelf life. Back to the matter at hand, no matter how small the joints are, there is a transfer of humidity/moisture, and the material, like the air, always seeks equilibrium. As a mention, ready mixed mastic is another, totally different matter.
    – Jack
    Commented Sep 29, 2015 at 16:57
  • So, I waited 14 days & then let the flood gates of children, dogs & company on it. No issues so far & it's had pretty heavy traffic. Honestly, I feel better knowing that the floor was done with modified anyway. It's an upper floor & though it's within spec., I feel like it could be more stable & maybe modified helps? I don't know what the actual advantages of modified are? Is it actually better in my case? I've had bad experiences with ready mix mastic. Though the containers at HD say it's good for floors & 12x12 tiles, it definitely is not! I'll never use it again cept maybe on back-splash.
    – maplemale
    Commented Oct 16, 2015 at 15:32


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