yet another tiling on ply question

Discussion in 'Tilers' Talk' started by erus, May 25, 2007.

  1. erus

    erus New Member

    Hi all,
    I am in the process of tiling inside the shower, we have made a stud wall of 3/4" marine ply (on the advice of our builder), we then sealed it with PVA, I have used unibond tile on walls waterproof adhesive (which states to seal ply with pva before use) with 9" x 6" mosaic effect tiles but for some reason they are coming off, what can i do, should i score the board to get a rougher finish, but then wont that defeat the purpose of sealing it all first, they seem to grab ok but for some reason are falling of within about 1 hour of being fitted, fortunately i have only done 18 tiles so if i have to rip them off to sort then its not too much hassle, PLEASE HELP ASAP as I am about to smash it all up
  2. jasonb

    jasonb New Member

    Smashing it up would be the best option, replace the ply with a tilebacker board, tank the shower area then tile with a powdered adhesive.

    Whats failing is the adhesive comming away from the PVAd ply or are the tiles comming away from the adhesive, if the latter then either the tiles are dusty or more likely in this hot weather the adhesive is skinning over before you press the tile into it.

  3. Morphine

    Morphine Member

    Hi Erus

    Agree with most of JasonB's points - Do a search on PVA in this forum and you'll soon find out it's a no-no!

    You've basically stuck the tiles to a wafer thin layer of PVA - probably why they're falling off.


    1. Remove any tiles you've laid

    2. Sand every inch of the plywood with decent sandpaper - only way to get rid of the PVA.

    3. Buy a Tanking Kit (BAL W1 I think?) from Topps Tiles or wherever. It's not cheap at £75 but if you follow the instructions to the letter is worth it's weight in gold.

    4. Tank the shower area.

    5. Buy a waterproof / flexible tile adhesive in POWDERED form - ready mix is Krap.

    6. Start tiling again.

    PS - If you're using mosaics as a border, put the upper layer of main tiles on first - Mosaics will follow any deviances in the walls, and you'll end up with ridges.

    Good luck.

  4. Dream Home Tiling.

    Dream Home Tiling. New Member

    Just to add, if you keep the ply in place you need to prime with an acrylic primer, deffo NOT Pva.
  5. starlight tiles

    starlight tiles New Member

    go over the pva with gypbond/green in colour,has sand in it.tiles will stick to it like ***** to a blanket.
  6. Spyder

    Spyder New Member

    Sorry to elbow in on this thread but I would value the forums opinion on a bathroom I'm doing.

    I'm in the process of clearing out the old fixtures and removing the floor tiles. I have had to use an sds hammer drill to remove the floor tiles and basically most of them have come away smashed and pulverised. The thing I would like to understand is this: the flooring is tongue and groove green chipboard, the floor has been sealed with a latex type product and the tile adhesive is a cement based product. If the tiles I'm having laid stick half as well I'll still be happy. Any ideas?

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