Tiles not set and falling off?

[Riker007]

Have done tiling myself many times and never ever had this problem. For some reason tiles won't set properly on wall, two have fallen off and a lot of moisture is present. When pulling off spacers that are stubborn a tile might come off, that was two days ago but customer rang to tell me two tiles have fallen off allegedly on their own on the top row. I think they are ceramic tiles, can't tell difference between ceramic and porcelain as didn't buy them, can check packet when I go back! About 200mm by 300mm so not huge tiles. Wall was painted surface in cloakroom, used ready mixed adhesive as always and this time they appear not to have set. Used this stuff many times before and stuff always set nicely after even after a few hours. Half of tiling I used the Cerafix (?) adhesive, other half was Wickes own brand heavy duty stuff which from memory set better than the other stuff. Until I go back and have a better look, I'm told its the tiles that were used with the Cerafix stuff that haven't set. Is it feasable to remove these tiles if haven't set and reapply another adhesive so they won't fall off again? Or replace tiles also? Could it be damp from this one wall (though was bone dry) or is it a funny paint I've tiled onto?
No didn't use any primer, never had to before when tiling straight onto a wall. No brown biscuit backing either. Whats the remedy for the wall now if reappling tiles, assuming they won't set if I wait long enough?

 

[Matt]

I would imagine it is due to the paint. Tubbed adhesive needs the moisture to be sucked out of it before it dries. With tiling onto a painted wall, the moisture won't have anywhere to go apart from the tile

 

[Deleted member 9966]

hi Riker

did you use a primer on the paint before you tiled? and did you sand back/score/key any of the paint before you tiled?

:welcome: to the best tilers forum by the way

 

[White Room]

Did the tiles have a brown biscuit back, they would be ceramic. I would have used powdered ahesive for that size tile, if they were porcelain and the walls are painted it has no where for the moisture to dry the addy will dry on the edges but the middle will remain damp for a long time.
If the paint was a vinyl silk it will not take any moisture whatsoever

 

[Sean fsy]

make sure the wall has not had any wall paper on it previously as we all know that the paste on the wall just goes back moist when adhesive is applied on to it.

 

[DHTiling]

How thick did you apply the adhesive..?

 

[Riker007]

Used standard wall trowel, whatever that size is. Plenty of adhesive all over tile. Covered all over tile evenly, and at the time they stuck nicely to wall and didn't move off at all..

 

[White Room]

How long have you been tiling out of curiosity ??

 

[Riker007]

Been tiling about three years. Plumber by trade, sometimes do tiling... So anyone any pearls of wisdom?

 

[White Room]

The tubbed gear has to be 3mm max bed, also the paint may have released itself from the wall due to the moisture from the addy.

I would visit the job and check the tiles, if they come off easy you may have retile.

The adhesive will come off the tile easy, use powdered from now on with the bigger tiles.