Ceramic tiles crazing ? Baffled ? Advise please !!!

[Gez2312]

Hi , thanks in advance for reading and replying !

Im in a bathroom fitter and I've been in the trade since leaving school , time served and about 15years experience

recently I tiled out a bathroom in ceramic high gloss tiles . Nothing out of the ordinary , used the same adhesive I always use, (ultra white flexi rapid) and tiled onto plaster walls which have been pva'd first and patched with board in some places where plaster was loose. The window reveals were a mess so I boarded them out with 6mm hardi board, I tiled as usual , wall had the usual bellys etc so adhesive was deeper in places, and if it's really deep I sometimes pack out with tiles cuts.

A few weeks later customer called and said tiles are crazing , called back , 90% of tiles had crazed on all walls !? Head scratching ! Sales rep from tile supplier came and saw and agreed faulty tiles , they were replaced and they paid me to retile (a nightmare job ! )

a few weeks later again and customer calls to say it's happening again !!!! Tile supplier now says it can't be the tiles , and refuse to even go and see the job.

im a loss as to why this has happened. Never seen it before or heard of it. Obviously don't want to leave customer unhappy , and will offer to retile again , but dont know the cause ! So do t want to waste my time and their time.

i would completely reboard room to eliminate plaster causing problem but wall is tight to door casing with room for adding (door latch nearly catches wall)

any advise would be great as I'm completely scratching my head , I've got some spare tiles and would love yo have them tested but can't find anywhere that will do it .

Ive never had an issue like this before and as I say same techniques I always use so can't see what's causing the problem

many thanks in advance for any help , hoping someone can shine a light on the situation !

 

[Ian]

Have you any pictures please?

 

[nybor62]

certainly sounds like the glazing has failed ,reasons for this .

thermal shock. poor manufacturing process,

some of your methods of tiling are wrong , imo . but saying that would'nt cause this problem

 

[Andy Allen]

Could be that your packing out the tiles to much using rapid set adhesive....when its drying it shrinks and on cheap tiles can cause them to crack...
Walls should be prep prior to tiling so only the recommended thickness of adhesive is used..

 

[Simons70]

Is Johnson tiles?Try to put one tile in watter for 24 h and see if happend again.Anyway,not PVA.....

 

[nybor62]

ive never had a probs with johmsons, done thousands of m2 with them

 

[Simons70]

We have a similar problem with glazed ceramic,if I'm not wrong was 450mm x250 mm.

 

[Dave]

Morning.

what size expansion joints are at the perimeters of the tiling. .?

Also some high glazed tiles with a soft biscuit can be prone to crazing and when you use a fast set adhesive this can as mentioned above
cause glaze shock as the adhesive cures/hydrates quicker than say a dispersion or standard set cement based.

 

[Gez2312]

They are 400x250 white granite look tiles , 3mm grout joints . Adhesive was rapid set , but never had problems before and tiled deeper ! Have tried a massive blob of adhesive on a spare tile but nothing ! Anyone know of anywhere to have them tested ? They weren't even that cheap ! About £30 a metre ! But are just ceramic white backed horrible bent, out of shape rubbish!!

 

[Andy Allen]

Did you put dabs of adhesive on the tiles and stick them to the wall?

 

[Gez2312]

No , not dabs fully covered the back of the tile and adhesive not deeper than 20mm . Can't see any reason for the crazing , even if they were dabbed ? I'm fuming that the tile suppliers have admit fault first time with no real queries , but now will not even go and look ! Surely if it was faulty tiles first time it can happen again ? And to blame me to the customer is wrong especially when they can't explain why it's happened!

 

[Diggy]

Manufacturer?

 

[Andy Allen]

The adhesive shouldn't be any thicker than 6mm on walls.....because the adhesive is rapid set it can dry to quick cracking the glaze...try using a slow set adhesive.....or ring the adhesive company tech depot tell them your fixing method and see if they can shed some light. .

 

[Gez2312]

They are a BCT granite white , I have got pics but don't know how to load them .

 

[Gez2312]

According to manufacturers , adhesive can be up to 20mm thick , I've used loads to this adhesive before and never had a prob with it. I've put it on deeper before and not had problems. It's just strange how this has done it twice now ? I'm happy to go and re do it again but don't want to waste my time if it is a problem with the tiles ! Anyone know of anywhere I can send the tiles to have them tested ?

 

[Diggy]

So are they Johnsons???????

 

[Gez2312]

British ceramic tile , had to ring and ask supplier ! I've used Bct before and not had problems (apart from being bent and out of shape!)

 

[Dave]

I use a lot of BCT tiles , which one is it ?

 

[Gez2312]

It's 'white granite' 400x250 ish , they agreed to replace them within 3 days of complaint going in which makes me think they have a had a problem . I kept some of the removed tiles as I thought someone would want to see them but got told just to bin them !

 

[Simons70]

One big construction company have the same problems with same tiles,in Hackney,if you want some details after was tested,please pm me and I give you all details.Anyway,is not the adhesive,in Hackney was used ready mix.

 

[Jelthetiler]

20mm adhesive? Would've been cheaper and quicker to re-skim with plaster! What's the name of the tile manufacturer?

Primer/SBR to seal stick areas. I was told that Mapei (for instance) will not guarantee their adhesive if it is stuck over PVA.

 

[Gez2312]

They were British ceramic tile .

20mm adhesive was not everywhere ! A lot of it was tight back to the wall , but it bellied in the middle. Can't see how this would make the tiles craze though ? And co incidentally the tiles are crazed more away from the deeper adhesive , also when I said pva'd I did mean primed ! Just force of habit saying pva !