Ceramic Wall Tile Failure - How?

[LarryTile]

Looking for some technical advice on these tiles please.

Our installers fitted this CaPietra Ceramic tile in Oct 22. CCL Wetroom floor, tanked plasterboard to walls. We believe they used a ready-mix adhesive such as BAL White Star as it looks too white from installation photos to be cement-based.

7 months later client reports marking. See video (good closeups towards the end).

CaPietra supplied more tiles from a different batch. Installer replaced 2 x runs to the bottom row end of May 23, regrouted and re-sealed. Client noted at the time that the new tiles were a different colour but they were told that they would dry out over time to match the rest. We heard nothing back after this.

Another 7 months later, client reports marking of the replaced tiles and additional marks to unreplaced tiles.

The tile is not crackle glaze but it does have a very dry body and the glaze only just lips over the edge. One of the showroom tiles actually has a fault to the face of it.

If anyone has seen failure like this, please could you let me know what it was put down to?

Many thanks, Laurence

 

[Dan]

Are the tiles warped at all?

 

[LarryTile]

We didn't notice that the tiles were warped. The installer only said they weren't cracked when he removed them.

 

[AliGage]

I've just done a shower room in a tile very similar to these.
@Dan I believe they are "warped" as such, they're not a flat face. Rustic and unrectified to give them a handmade look. They very well maybe handmade.

As it's the bottom row, and a long the back of the linear drain mainly, my answer would be water ingress. Changing the colour of the biscuit.
I can't tell from the pictures how the raw edge at the bottom of the tiles (behind the drain) are protected by this. The rest of the room has a bead of Silicon I can see.

As you show in the pictures, the edges of these tiles are, to a certain extent unfinished. Droplets/run off from the shower could be hanging on the edge of the tile and being absorbed up into the very soft biscuit.

Replace the bottom row and perhaps seal the edges of the tiles using an impregnating sealer.
Would do this prior to fixing any and make sure you don't get a colour change/bleed through the tile from it? 🤷🏻‍♂️

Hope this all makes sense, I'm nursing a hangover lol