Advice Please : What Has Caused Fine Cracks In Bathroom Tiles?

[A274]

I'm a customer not a tiler but seeking advice please:

I had two bathrooms fitted in Jan/Feb and in late March noticed some tiles had cracks in - fine cracks in the glaze in webbed patterns (NOT directional cracks that you might see where movement has occurred in wall behind tiles). See attached image. In some places the cracks are even worse and seems as though the whole tile has cracked not only the glaze.

I called the builder back and he is blaming the tiles. However I don't think this is the case as the problem only occurs on some of the walls and not others (all walls were tiled from the same batch of tiles).
The difference between the surfaces that have cracked and the ones that haven't is the thickness of the adhesive used. Where it has been thinly applied - (<6mm which is the max depth you should use according to the instructions on the adhesive packet - 'Topps Rapid Set flexible') the tiles are fine, but where it has been used at greater depths (in some places as much as 24mm has been applied) there are cracked tiles. About 13 m2 of tiles are affected.

I would greatly appreciate any advice on what the cause is and how to fix the problem.

Additional details:
Tiles are Topps diamond white matrix tiles which I know are 'cheap' but I used them in a previous bathroom and inside the shower with no problems at all (installed by a different builder/tiler).
Tiles have been applied to a variety of surfaces: wedi board, waterproof ply, waterproof plasterboard, existing plastered walls, but the walls were not made level / square at this point in the process, instead the builder relied on thick application of tile adhesive to correct.
The cracks have only occurred where the tiles were applied over wedi board or plywood, not to any of the existing plastered walls or 'boxed in' structures built from waterproof plasterboard.

 

[Kevbos]

I would say it's a hard one because if tile joints are not giving. But the tile is. Then the tile is the problem. You gave multiple surfaces to tile on all of which. Expand differently to each other. The glaze has failed not the adhesive used

A high gloss glaze does not have any flexibility

Thick bed adhesive has shrunk and tiles are soft with a very thin glaze. Part fixer error and part poor tiles.

Tilers always get blamed for the preparation. The glaze would not crack unless they cheap and under stress. No matter what glue used if the joints have not cracked. Which is weaker than a tile then tile at fault

 

[One Day]

Poor quality tiles which are unfortunately showing up poor fixing. Had they been a porcelain tile, you wouldn't have had this issue.

 

[Kevbos]

Poor quality tiles which are unfortunately showing up poor fixing. Had they been a porcelain tile, you wouldn't have had this issue.

Joints would have cracked instead I reckon

 

[Kevbos]

Poor quality tiles which are unfortunately showing up poor fixing. Had they been a porcelain tile, you wouldn't have had this issue.

I'd say if tiles are not falling off and joints not cracking. But glaze is. Then maybe the tile needs a fixing guide attached. As a tiler I hardly ever get perfectly flush and flat walls to tile over. Adhesive suppliers always say depth you can fix tiles onto. Tiles do not. If they are still stuck and joints not cracking. Then tiles at fault

 

[macten]

I'd say if tiles are not falling off and joints not cracking. But glaze is. Then maybe the tile needs a fixing guide attached. As a tiler I hardly ever get perfectly flush and flat walls to tile over. Adhesive suppliers always say depth you can fix tiles onto. Tiles do not. If they are still stuck and joints not cracking. Then tiles at fault

24mm bed of adhesive. Sort wall out first.

 

[Kevbos]

Topps Rapid Set can deal with that depth. Not that I'd ever use rapid on walls. Not being funny. But customer seemed to know alot about prep and the depths of adhesive. Walls were not flat or prepared properly. But if tiles are not coming off or joints cracking. Then the tile which was stated as cheap probably Chinese or Turkish. Is the problem. You can't say you knew there were many different substrates and exact depths of adhesive used. Yet tiles still stuck. And blame fixer after. Sounds like a multitude of sins. I would have refused to tile it. But I reckon alot more to that story

 

[Kevbos]

Topps Rapid Set can deal with that depth. Not that I'd ever use rapid on walls. Not being funny. But customer seemed to know alot about prep and the depths of adhesive. Walls were not flat or prepared properly. But if tiles are not coming off or joints cracking. Then the tile which was stated as cheap probably Chinese or Turkish. Is the problem. You can't say you knew there were many different substrates and exact depths of adhesive used. Yet tiles still stuck. And blame fixer after. Sounds like a multitude of sins. I would have refused to tile it. But I reckon alot more to that story

24mm bed of adhesive. Sort wall out first.

I learnt my mistakes early as a tiler. Tiles are now harder and harder to keep straight flat etc. I wont touch such jobs with a barge pole for this reason. You go cheap this is what happens. Client saw the poor prep said nothing. They tried to make good job. The tiles have crazed. Who do you blame

 

[macten]

Topps Rapid Set can deal with that depth.

Really?
Tiles couldn't deal with it though.

 

[Kevbos]

Really?
Tiles couldn't deal with it though.

Looks like it as they not falling of or joints cracking. Quite simple really.

 

[jobdone]

I have seen this before due to bed depth being to deep and stressing the tile but it was over painted walls so had delaminated, dried, shrunk and cracked the tile.