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Community and Q&A

Prepping a concrete floor for tile

slugboy6000 | Posted in General Questions on

Hi there,
How clean should a concrete surface be before applying ceramic tile?
I’m prepping a concrete slab floor that had vinyl tile stuck to it for decades.  With the vinyl tiles removed, there’s still a thin yellowish resinous adhesive stuck to the concrete.  It’s really hard to scrape off.  Does it need to come off (have any tips)?


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  1. Expert Member


    Angle grinder with wire wheel? The BB stores also sell adhesive remover.

    Are you putting the tile directly onto the concrete? Not meaning to complicate things, but best practice is to include a decoupling membrane between the slab and tile, which helps both avoid cracking and any potential moisture problems.

    1. slugboy6000 | | #3

      I won't be installing a decoupling membrane, although I do like the idea of giving the next guy an easier time if the floor needs to be torn up. I like the wire wheel idea, I'm not dealing with a huge area. I'll move up the toxicity scale and see what chemicals put a dent into the adhesive... I don't want to lose too many brain cells. The adhesive remnants are so thin that I shouldn't have any trowelling troubles. Thanks guys.

  2. Expert Member
    NICK KEENAN | | #2

    I dealt with a situation like that by renting a floor sander. You may want to talk to a tool rental place and ask them what they recommend.

    I've never had a problem with thinset not sticking to concrete. However, it's hard to get an even coat if the underlying floor isn't smooth, the trowel will hang up. If the mortar isn't even you'll never get the floor flat.

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