When stopping and starting a tile job, you are left with the cleanup of the thinset that extends past the tiles that have been set. This thinset can be scraped up with a trowel, but leaves a light residue. Upon resuming the job, does this residue need to be vacuumed up with a brush and vacuum, wiped with a sponge, sprayed down with water, or can thinset just be placed directly on top of it?

2 Answers 2


I used a 3" scraper - nice flexible blade which left the minimum possible.

When continuing the next day, just de-dust and fresh stuff straight on works a treat and did that for small tiles, big floor tiles and a wood parquet...

I would also put guide lines on the wall or floor to show the "glue" limits per section to be worked on...

  • What do you mean by "de-dust"? Do you vacuum it up or wet down or sponge off?
    – Evil Elf
    Mar 11, 2019 at 18:57
  • 1
    I gave it a vacuum - just to get loose stuff off...
    – Solar Mike
    Mar 11, 2019 at 19:10

It depends on the thickness of the thinset you are laying down.

If you are doing a shower with large tiles and back butter in addition to setting I would do the following:

  1. Scrape off as good as possible.
  2. Hit it with a tiler's sponger (course on one side - these are like less than a dollar at HF in the US). You want to sponge the last row of tiles very well - nothing on them.
  3. Do not sponge off the left over from the scraping except for the first inch from the last row - try to get all or most of that.
  4. The next day hit it quickly with a wire brush - the left overs. If you don't have a wire brush handy then use another type of brush. No brush then move on step 5 but do it more vigorously. No need to be harsh just get the loose stuff.
  5. Sponge it with a very wet sponge to get area moist and clean up dust and loose particles.
  6. Restart.

If you are doing tiles that have less thinset:

  1. Scrape off as good as you can with a trowel.
  2. Get a 6-10" putty knife and scrape off all remnants.
  3. Thoroughly sponge and wipe area.
  4. Repeat step 2.
  5. Repeat step 3.

Try not to stop a smaller tile job mid-day. Having a small amount of thinset on drywall or back board creates a spot that isn't as binding as the rest. In the first example it is OK because you will wet previous day's scrape marks and there will be a thick coat that binds to the lateral scrapes. If applying minimal thinset though this does not work well and you really need to clean the area as well as possible, which might not always be optimal.

And I do not vacuum. Just my preference. I find the vacuum hits thinset not cured and cracks it causing more of a mess. Also when I have vacuumed then sponged, the sponge still picked up a ton so why bother. But the biggest thing is on second day if there is anything left I like it to be wet before I start adding more thinset. Unless I got an area 98% clean I am wetting it.

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