Is it acceptable practice to install pool tile mosaic without any thinset or mortar securing the mosaic tiles to the pool surface?? My pool contractor did this with a large turtle mosaic and now the tiles are falling out.

He tells me it is common practice to just secure tile mosaics with just the grout and plaster surrounding it - and no thinset/adhesive between the tiles and pool surface. I heard from someone that ANSI A118.5.2.4 discusses specific installation of ceramic tile mosaics in wet environments (pools, spas, showers), but I have not been able to find the exact text of the standard. Searches keep landing on product info. Can anyone copy-post or lead me to the relevant text?

Likely the pool will have to be drained and the entire 3' by 4' mosaic torn out and replaced (or leave a turtle shaped patch...?) That sounds like it could be expensive. IF the contractor was not following acceptable standards of tile installation, he needs to step up and fix this. Right now, he does not sound like he is ready to do that.

Can anyone provide insight as how to handle this. Any links to resources (such as ANSI, or local standards) would be fantastic. We live in California, Santa Clare County. Thanks, Kevin

  • How does one install tile without mortar? Was grout used as mortar? What plaster are you referring to?
    – isherwood
    Dec 14, 2015 at 15:23
  • There are plaster mixes that can be used to bond tile to pools. Shit the ancient romans used to do it all the time. I doubt your contractor has the plaster mix to support this and I doubt he is an ancient roman - I kid because plaster is still used in very high end finishes to this day. I would assume that the plaster mix he has would dissolve and fail.
    – DMoore
    Jan 13, 2016 at 17:37

2 Answers 2


A Google search for "ansi A108.5.2.4" (no quotes) finds a PDF as the first hit containing: screenshot

  • Thanks! The contractor has suddenly changed tack and seems to be willing to take responsibility (fingers crossed). Kevin
    – Kevin Y
    Jul 17, 2015 at 18:55

Take a look here . I know it is not your county but it may close.

  • Thanks WarLoki. There was a lot of details about the construction, but very little about tile except where it needs to be. Nothing about how the tile should be installed. I heard from someone that ANSI A118.5.2.4 discusses specific installation of ceramic tile mosaics in a wet environment, but I have been able to find the exact text. I tried searching for it, but keep landing on product info. Can anyone lead me to the relevant text? Thanks!
    – Kevin Y
    Jul 16, 2015 at 4:49
  • 3
    -1 Link only answers become useless when the link goes bad and are frequently confused with spam. Be sure to provide context around the link and quote relevant content in case the link goes bad. See how to answer for more details.
    – BMitch
    Jul 16, 2015 at 13:07
  • Sorry, just trying to help.
    – WarLoki
    Jul 16, 2015 at 13:49
  • Thanks WarLoki. Can anyone post the ANSI text from A108.5.2.4 ? I have been told this specifically addresses installation of ceramic mosaic tiles in a wet enclosure (ie, spa, pool, shower, water play feature, etc...). I don't know where to find them. Thnx
    – Kevin Y
    Jul 16, 2015 at 19:54
  • Thanks for your help. After my last conversation with the contractor he admitted that it appears that the turtle was not installed correctly. Apparently they set mosaics into the plaster and then set them by troweling the top layer of plaster. This is why the loose pieces are in the center and not the head or fins.
    – Kevin Y
    Jul 17, 2015 at 19:18

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