I’m looking to replace my kitchen backsplash. It was previously regular tile and I’m going to replace it with glass/porcelain tile mesh backsplash. I have removed the old tile and it appears to be drywall with the old adhesive residue.

I have watched a video where it was recommended to apply thinset to the wall to smooth it across, let it dry completely, and then separately use adhesive and stick the tiles.

The wall is definitely not smooth/flat now. Do you think it’s a good idea to smooth out the wall with thinset first?

Also, do you recommend I apply mastic With my trowel for installing the backsplash or is thinset ok? I read that mastic is recommended for glass tiles as it dries faster but not sure. This is my first time installing tile/backsplash.

This is the tile I’m looking to install.

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  • 1
    Are any of those individual new glass tiles clear or translucent such that the backing would show through?
    – Michael Karas
    Jul 15 '20 at 9:23
  • Don't confuse "grab" with "set" when it comes to adhesives. Mastic actually dries slower behind non-porous tile, but it secures the tiles quicker because it has a more sticky body. It has to dry to cure, though, which happens over a long period of time behind glass or porcelain. Mortar cures more quickly in such situations because it doesn't need to dry to harden.
    – isherwood
    Jul 15 '20 at 18:25
  • The answer to your actual question depends partly on the trowel notch size you plan to use. Smaller notches (and most v-notches) require a smoother surface. So what's the story?
    – isherwood
    Jul 15 '20 at 18:26
  • The individual tiles are small themselves - less than 2 cm height, so I was assuming I need a smaller trowel and I have picked up a 3/16 trowel. Please let me know if my assumption is incorrect. If I’m reading your response correctly, you recommend thinset over mastic for these glass/porcelain tiles?
    – Nis
    Jul 15 '20 at 20:11
  • Per installation instructions - "The mosaic, unless otherwise specified by the customer, is usually laid on white mastic or thinset to avoid altering its color White thinset is usually recommended to use for the glass and other light or transparent product to avoid discoloration of the background." Jul 16 '20 at 5:16

Royal Pain the ars to make that wall smooth and workable.

I would remove the drywall and install 1/2" Denshield. No need to remove the cabinets. the Denshield will give you a nice solid surface to work with.

Added benefit to this is that while the wall is open you can change the electrical box's to adjustable depth one's, once your tile is on you can adjust the box, by turning a screw, so it is the correct depth.

I would use a White mastic for your semi-translucent glass tile.

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  • Thank you. There are all great recommendations, which I’ll review and determine best approach. To the first question - the glass tiles are stained but are still clear (I can see my finger through them). For the tool question - it’s two different tools caught in the perfect angle!
    – Nis
    Jul 15 '20 at 17:43

If the adhesive can be scrapped/sanded off and you have a fairly smooth wall then you can fill the low spots. If the ridges from the adhesive are raised then you're going to spend a lot of time trying to smooth out that wall. I wouldn't use thinset because it doesn't sand well. I'd use joint compound with a good primer.

It looks like that drywall can be easily cut out and replaced which is something you may want to consider.


I encountered a situation installing a backsplash on a Sheetrock wall where the wall was distinctly not flat because of the framing it was mounted on. I elected to remove it from the counter to the bottom of the cabinet and install new Sheetrock with some furring strips to flatten the wall.

This is probably not much more work than trying to flatten what you have there with joint compound.

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