I am redoing out laundry room and would like to put tile on a wall that is already painted. The paint is a satin finish and is in good condition as it is only 2 yrs old.

Is it ok to just spread the adhesive and install directly on the painted wall? Or should I do something else to prepare it?


3 Answers 3


The safest way to do that is to apply a scratch coat first, using whatever mortar or mastic youll be using to install the tile. Make sure you let it cure out all the way. Most mortars and some mastics heat up as they cure. This means it can it can make the paint release from the wall, much like removing wall paper.

  • So is the point of the scratch coat to: 1) create a rough surface or 2) determine if the paint will peel off? Or both?
    – Dflaher
    Feb 11, 2018 at 20:34
  • Also, how thick is this scratch coat?
    – Dflaher
    Feb 11, 2018 at 20:35
  • Its to give a better bonding surface for the tile, and incase the paint as well. Doing the scratch coat first without tile allows a lot more airflow so any heat build up dissipates. Doesn't need to be thick at all, use the flat side of the trowel or a mud knife and just coat the wall. Fill in any texture and make a smooth surface, just a scratch coat, doesn't need to be perfect. And yes it can show how the paint will react too.
    – user81381
    Feb 11, 2018 at 22:41

Scratch it up with coarse sandpaper, maybe as fine as 100 grit or as coarse as 60, or perhaps as rough as 40 or 32 grit. no magic number here. Just enough to allow the mastic to grip to. Mask off the edges to protect surrounding areas from the mastic and sanding, sand enough to see scratches on the paint, no need to burn through to the paper.


I agree with a simple surface roughing with sandpaper as @Jack suggests. I would take a different strategy to preserve the wall later down the road if you need to change out a tile, or want to tear it down. I would spend the extra and use a backerboard so when you pull down the tile it would potentially damage the backerboard opposed to the sheetrock. Typical backerboard installation suggests using backerboard screws, but using a broad crown stapler or galvanized nails would also work, again to better help preserve the original wall.

I would use this type of backerboard found at https://www.homedepot.com/p/James-Hardie-HardieBacker-3-ft-x-5-ft-x-1-4-in-Cement-Backerboard-220022/100183556 James Hardie 1/4" backerboard You can also use this type found at https://www.homedepot.com/p/USG-Durock-Brand-1-4-in-x-3-ft-x-5-ft-EdgeGuard-Cement-Board-170215/304218901, but I don't like it as much Durock 1/4" backerboard

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