Removed tile from a plywood subfloor and there is a very small ammount of uneven thinset residue like 1/16" in spots randomly scattered. Not worried about the level as it appear flat but worried when I screw the 3/8" underlayment down over the top before tiling that I'll get some crunch noise over time. I have a random orbital and angle grinder, its a small bathroom. Should I just hit it with some 80 grit or get one of the diamond head angle grinder discs. Seems like they may be overkill and I might make it more unlevel. Or is there a product I can apply before the underlayment? Not sure about self leveler poured between the layers cracking after screwing through. Other have suggested rosin paper 1 or 2 layers

1 Answer 1


I had a similar problem and I just ran a three inch cold chisel over the areas that were a problem. Granted, you might not want to do a large area like this but for a small bathroom, it worked great. No thinset dust to breath, it just shaved the residue off the sub floor and I swept it up. Just a thought. You could use a regular chisel but you'd have to put a new edge on it afterwards.

  • Thanks, I've removed the majority of the thinset with a hammer drill and SDS chisel bit, whats left is a scattered amount of small thinset from 3/8" wide x1/16"tall x 1-2" long trowel lines scattered across the whole floor, would take awhile to removed with a flat chisel but I'll give it a try tonight
    – redlude97
    Commented Aug 31, 2020 at 19:06
  • @redlude97 OK, that's a lot.. ya got knee pads??
    – JACK
    Commented Aug 31, 2020 at 19:34
  • 1
    along that line of thought, try a scraping blade on an oscillating saw; it does the same thing only lazier.
    – dandavis
    Commented Aug 31, 2020 at 20:26
  • 1
    @dandavis We all love "lazier".
    – JACK
    Commented Aug 31, 2020 at 20:35

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