Acid wash?

Discussion in 'Remodel Forum & Blog' started by HoneySuckle, Oct 29, 2007.

  1. HoneySuckle

    HoneySuckle New Member

    Messages:
    126
    Why does the tile contractor recommend using an acid wash on my kitchen floor (concrete) before installing tiles? The floor has been exposed for several months since we removed the vinyl. Most other contractors said it needs some prep, but no one mentioned acid wash. Is this normal procedure?
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,515
    Location:
    Cave Creek, Arizona
    acid

    Partly to etch the floor so the new adhesive will stick better, and also to remove any remaining adhesive, wax, etc.
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,924
    Location:
    New England
    Sprinkle some water on the floor and see if any of it is absorbed. If there is a lot of old adhesive or other contaminants on the floor and water isn't absorbed, the mortar won't stick. An acid wash may not help...usually it takes mechanical work to get it off - either a razor scraper or if really bad, a scarcifier (basically a big grinder to take the top layer off). If the concrete has a really smooth surface, etching it can help. The better scarcifiers come with dust collection. They can also help take off high spots to level the floor.

    If water gets absorbed and doesn't just bead up, use of a thinset mortar specified for use over cutback will suffice. This will usually be one of the better, modified (laytex addatives) thinsets.

    Are there any cracks in the existing floor? They need to be handled, or they may telegraph into the tile. If any of the cracks (if there are any) are at different heights (one side either rose or fell in relation to the other), generally, the recommendation is to not tile it.
  4. HoneySuckle

    HoneySuckle New Member

    Messages:
    126
    No cracks, which is amazing. We did scrape as much as we could off, though there are small areas that might need a little more scraping. That was HARD work:eek:

    This is what he plans to use: Ultraflex II gray, and sanded grout. Sounds okay? Water did not absorb.

    20 x 20 porcelain.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,924
    Location:
    New England
    As I understand it, if it won't absorb water, whatever is left will act like a bond breaker for even the best thinset. Ask this question over at www.johnbridge.com. There are lots of tile experts over there. Unless I'm missing something, though, I think I'm right. Doesn't hurt to double-check.

    You are using a razor scraper on a pole? Yes, it is hard work. If you can't get enough off, or if it actually penetrated the surface, you may need the scarcifier.
Similar Threads: Acid wash
Forum Title Date
Remodel Forum & Blog Advice on Concrete acid stain Jul 1, 2006
Remodel Forum & Blog Muriatic Acid-Removing mineral deposits from glass Mar 31, 2006
Remodel Forum & Blog Indoor Concrete Acid Stain Flooring Feb 9, 2006
Remodel Forum & Blog Installing Dishwasher Aug 18, 2014
Remodel Forum & Blog Addition of bathroom and washer Dec 16, 2013

Share This Page