Tile adhesive still wet

[sparky3659]

hi all

About a week ago, I tiled my bathroom using big 600x300 porcelain tiles. In the shower area, I waterproofed it using the Mapai waterproofing kit, and decided to use a different adhesive to the screwfix own brand, for that area. I bought and used ' unibond shower adhesive for large tiles'. Now, imagine my disappointment when I checked them today, and found the tiles have a squidgy sound to them when I pressed them. Basically, the adhesive hasn't set at all. Surely it can't be because I waterproofed the area using that Mapai stuff?? Any ideas? I don't really want to remove them all and do it again, but I guess I'm going to have to. If I do, what adhesive would work well with the Mapai waterproofing?

 

[joe-90]

You'll get all the usual suspects saying "Unibond is rubbish". That's not the problem. Tub adhesive sets by the water in the mix being removed, wicked away by tile and wall.
If you have large, low absorbency tiles and a waterproof wall then that cannot happen. The water remains in suspension like in the tub and the adhesive doesn't set, which is what you have. What you need is a powdered cement based adhesive that will set by chemical action regardless of the surface. Unibond do one that is fine, I use it regularly.