Help, Some tiles are falling off the wall!

[Chemlagh]

My husband has been tiling our bathroom. It is a new build house. The walls are gypsum plaster coated with acrylic primer (Larsen). The tiles are ceramic 300 x 400 mm and the adhesive is Profix adhesive standard set flexible wall and floor tile adhesive (white). Some of the tiles have started to fall off the wall. They have been on the wall for about 6 weeks and nothing has been grouted yet. Any advice would be helpful. We are using the adhesive as recommended by the shop. What are we doing wrong? How can we sort the problem out?

Thanks

 

[Ian]

Welcome along to TF. Has the tile come away from the adhesive or adhesive away from the wall?

 

[Diamond Pool Finishers]

Hello and welcome to the forum , did he spread the tile adhesive on to the wall with a come patten ?

 

[DHTiling]

Are the walls painted..?..

 

[Chemlagh]

Adhesive away from wall. Adhesive stuck firmly to tile

 

[Chemlagh]

Adhesive was spread onto back of tile using a comb using a 6mm comb spreader.

 

[Chemlagh]

No, its a new wall in a new build house. The walls were plastered last August and tiled in January. Gympsum plaster wall sealed with acrylic primer applied as per instructions, diluted with water 1:1 first coat, second coat - neat, tiles stuck when tacky.

 

[DHTiling]

There is the problem... if the primer skinned then you have no grip to the plaster capillaries.. and the skin is the only thing holding the tiles in-situ.

 

[cam_low]

I'm sure my Ardex says only one coat ?

 

[White Room]

Hi and welcome....

 

[Chemlagh]

Thank you. What can we do to sort this out? The adhesive instructions say when tiling onto plaster use a suitable primer.

 

[DHTiling]

It all depends on how much the plasterer polished the surface of the skim coat, this will affect the way the primer can soak in without skinning ... sometimes you have to key the plaster surface before hand...

Also just to say , the 6mm trowel is not a deep enough notch.. as for a resolution, then sand the walls , prime with 2 coats of primer at 4:1 water to primer ratio, that will be sufficient to prevent ettringite..

 

[Chemlagh]

Thank you very much for your advice, we will give that a try . We probably should have painted the walls!!!

 

[bugs183]

Did you say you combed the adhesive onto the tile? Did you comb adhesive onto the walls as well?
If you haven't combed adhesive to the walls then there is no mechanical key for the adhesive to bind to the plaster, this is why it has fallen off.
And no you shouldn't paint walls that are to be tiled, you prime according to the manufacturers instructions.