Cracking glaze months later

[Perfect Tiling]

Hi all. I've recently tiles a kitchen splashback with 300 X 100 X 8mm johnsons ceramic tiles onto a solid wall. 3 months later the customer calls me to say 2 tiles are cracked. Looking at the job I find 4 further cracked tiles but it's the glaze that's cracked. The cracks run in different directions.....like a crack in a windscreen. I thought it was the heat from the hh o but then found another one cracked away from the hob. I then remembered a job I did last year with the same tiles and went to look at it.....finding some tiles with the same issue. Walls were primed and adhesive was BAL SPF white. The cracks weren't there when I had completed the job. Any ideas. I'll try to add a pic.....but you'll need to zoom in. Thanks

 

[WetSaw]

"Johnsons tiles" is the answer.

 

[One Day]

Did you breath near them?!

Serious answer - Johnsons 8mm (more like 6mm) are very weak tiles.
There are loads of instances of them fracturing simply from the stress of adhesive curing underneath.
I'd suggest that BAL SPF is too strong for the tiles and a super-rubbish ready mix would have been "gentler".

 

[Perfect Tiling]

Ha.....that's what I said to the supplier. I usually tell customers not to buy british tiles as they are usually crap. They were 8mm thought.....they used to be 10mm and I'm certain they were the Savoy range. The problem is.....who pays to redo it.....cos it's not my fault apart from me agreeing to take on the job and using good quality materials......apart from the tiles....which were customer supplied

 

[WetSaw]

If I'd fitted them I'd repair it. You had the opportunity to refuse to fit them. As said, use a dispersion adhesive and they'll probably be OK. Possibly too thick bed of bagged adhesive and a little shrinkage is enough to crack poor quality tiles.

 

[J Sid]

don't know these tiles, thankfully, should they have sealed, before fix or after?

 

[Waluigi]

Another case of the wonderful British Tile Manufacturing Industry.

 

[J Sid]

ok, I'll put it another way..... Did you sealer them?
is the problem happening near a wet area or cooking / steam area?

 

[Time's Ran Out]

Crazing is an inherent feature of all ceramics. It says it on all the boxes!

 

[One Day]

Crazing is an inherent feature of all ceramics. It says it on all the boxes!

No it's not. Just those made by bct!
I've read the same rubbish...

 

[Perfect Tiling]

I didn't seal the tiles as they weren't crazed. I've used crazed tiles many times and seal both before and after grouting.....but you wouldn't seal uncrazed ceramic tiles as nothing to seal!!!! Customer doesn't want the damaged tiles replaced as he says the others will probably go same way. Most tiles are above the hob and one above the toaster so heat probably to blame as well as crap tiles.