Tips for Shower tile Install with Mastic?

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We recently had a friend of my husband's help him install a shower system called Prova and tile our shower. While researching grout, I stumbled across something saying that you should not use mastic in a shower? That is what they used! We will have glass up to the soffit we build above the shower so the only ventilation from the shower will be an exhaust fan in the shower and a transom glass window above the shower door to ventilate the steam. I asked a tile friend of ours about this and he stated that he would rip out the tile(down to the studs)and start over! He said that you will have issues with mold and possibly having tiles fall off if they are exposed to too much moisture. What should we do?? We are ready to grout! We are afraid that if we spend the money on the marble pieces that are to go on the shower seat and shelves and the glass walls and door that we will have to waste them if we end up having to rip out the tile in the future. Help!!

  5 answers
  • Dee Dee on Jun 20, 2018
    This website will give you the answers you need about using mastic vs thin set.
    It can be used but not advised.//www.tiletools.com/mastic-vs-thinset-use/

  • William William on Jun 20, 2018
    There wer many instances that I and my crew used mastic in showers, around tubs, and on tub surrounds with no problems. If we were tiling a ceiling in a shower or tub area thinset will not hold to a ceiling so we used mastic for the whole job. Some customers did not have the funds to remove tub surrounds or one piece tub and showers but wanted tile. That is where we used tile mastic. Of course we couldn't guarantee the job but it worked. As long as the tile is grouted and grout sealed there should be no problem.

    • See 1 previous
    • Marti Sheehan Moon Marti Sheehan Moon on Jun 21, 2018
      We are just so concerned that if we spend the money for the marble on the shower seat, threshold and shelved along with the glass walls and door that we may have to tear the tile out later, those things will have to be trashed and purchased again. Its a total crap shoot. the marble and glass cost around $3000 alone! tearing it out is a total nightmare as well. neither option is good....

  • Your tile friend is correct. I am so so sorry. But better now than when totally complete. Is this a "remove and replace" job or a total remodel? Were permits pulled? Does not sound like it. You live and learn. Don't beat yourself up. Now you know to research thoroughly before starting your next project. This is an excellent learning experience, albeit a bit costly, but not the end of the world.




    Keep us posted. Sorry to be the bearer of not so great news.

  • Sharon Sharon on Jun 20, 2018
    You asked your professional tile friend his advice, and it sounds like you're doing a quasi steam room shower, and I agree with your friend..... sorry its not what you wanted to hear from both of us, but you could get a 3rd professional opinion.

  • William William on Jun 21, 2018
    I have not had any problems with using mastic when needed even in wet areas through the years. Since then technology and products have changed. Your concern is warranted. A lot of sites recommend not using mastic in wet locations. Your friend would be correct to remove everything down to the studs and start over. Use cement board over the walls, seal all joints with fiberglass tape and thinset. Then use thinset to set the tiles. You can also use a waterproof membrane over the cement board before tiling. Which are newer products.