Tanking and adhesive compatibility

Discussion in 'Tilers' Talk' started by ThreeDog, Jul 17, 2021.

  1. ThreeDog

    ThreeDog New Member

    Hi experts,

    Im having my bathroom tiled in a few weeks. When the tiler was here for the quote I mentioned that I intended to use the mapei wall tanking kit (see pic) before the tiles go on as the existing walls around the shower are dot and dab plasterboard with plaster skim finish. He said the tanking wasn’t really necessary, just an added expense that won’t make any difference as the adhesive and grout are both waterproof anyway, and that if anything it will be less reliable as the tiles will then only be stuck to the tanking, and not the wall itself. Any thoughts?

    I think after reading such good reviews on the product I am leaning towards using it anyway, belt and braces type thing. If I do, do I have to ask the tiler to make sure he uses Mapei branded adhesive to match the tanking? Or would any brand of adhesive be fine on top of the mapei tanking system?

    All advice appreciated.
     

    Attached Files:

  2. pppmacca43

    pppmacca43 Super Member

    I used bal tanking kit on mine, really easy to use. Tbh I’m kind of the same opinion of the tiler, if water gets behind your tiles, is the tanking kit really gonna make that much difference!? But like u I went belt and braces.
     
  3. ThreeDog

    ThreeDog New Member

    Thanks for replying. Do you know if your tile adhesive was also bal brand? Or something different?
     
  4. pppmacca43

    pppmacca43 Super Member

    Yeah it was bal adhesive and grout. Like u I wasn’t sure of cross compatibility so went for the same tanking kit as the adhesive I already had.
     
  5. ThreeDog

    ThreeDog New Member

    Just to follow up on this:

    Tiler informed me he would be using ‘ultra tile fix’ branded adhesive, so I got the matching brand tanking kit the other day, applied it tonight. This kit specified ‘no priming required’. While applying it I noticed some small hard bits in the mixture, no real bother, I thought I’ll let it dry and then pick them off after. About half an hour after applying the first coat the tanking was dry so I started to pick these little bits off of the wall. In picking them off it left a small bubble in the dry tanking, so I picked at this bubble… (couldn’t help myself, I hate seeing an un-stuck edge) and one thing lead to another and 3 seconds later I had peeled the entire sheet of tanking off of the wall in one big wall sized piece. Very easily I might add. Couldn’t believe how easily it came off. This was a plastered wall. Definitely dry. I’ve now lost all confidence in this tanking stuff on plastered walls. One of the walls is bare plasterboard, no issues with that wall, it’s bonded nicely with the paper surface. Anyone else had a similar experience? I know under normal circumstances once tiled, the tanking would never be able to peel like that, but it just doesn’t seem right that it came off so easy, didn’t seem to have bonded to the plaster very well at all. (I did wipe the surface with a damp sponge before tanking to ensure no dust was sitting on the surface and then let that dry). Maybe all tanking peels off like that if you try, and I’m just the only one stupid enough to do it?
     
  6. AnotherTopJob

    AnotherTopJob Screwfix Select

    It doesn't sound right, however you only let it dry for half an hour, which doesn't seem very long.
     
    Last edited: Jul 29, 2021
    pppmacca43 likes this.
  7. pppmacca43

    pppmacca43 Super Member

    I primed my plaster wall before tanking, that was the bal kit tho
     
  8. ThreeDog

    ThreeDog New Member

    I tried it again this morning after drying overnight, still peels off just as easy…
     
  9. AnotherTopJob

    AnotherTopJob Screwfix Select

    You could try sanding or lightly scoring the plaster and maybe priming but I'm not sure if it would help.
     

Share This Page