Adhesive bulging problem

[Andy Allen]

@Paul C. Could probably help..

 

[Italy]

It was a quick set powder adhesive
Uniflex White Wall & Floor Tile Adhesive 20kg

I got the tiles and adhesive from wallsandfloors. I understand many, many tiles of this make and type has been sold without any issue. I have tested the tiles for expansion and contraction and wetting them so see if I can detect any movement, but I can not detect anything. I would say the tiles are ok as far as I know. Well! I hope so because I have bought some more to redo the showers with a slow set adhesive and a different tiler so I can cut out all the elements I can change in the hope the issue will not be repeated. I am not blaming the supplier here or the tiler for that matter as it remains somewhat inconclusive.
I do feel that if the adhesive is so susceptible to whatever this issue is, then I question its use and purpose or at least there should be some highlighted warning on the bag directing the tiler to specific use instructions. I understand Norcros make the adhesive.

try with the hot and cold shock.
put them in the freezer and check the planarity
Then the heat and check the flatness

 

[Old Mod]

I do know one person that could possibly shed some light on this issue.

His name is Colin Stanyard, he’s a technical guy at Domus Tiles Clerkenwell, he also worked as a tech guy at Mapei Adhesives, so if anyone may have an insight, it could be Colin.
I’ve no idea if he would or even could advise because of their corporate policies, but I’d say it was worth a shot.
There’s no real point making the call myself as there will be questions I just won’t be able to answer, and then it just gets complicated.
But that’s exactly where I would start trying to unravel what’s happened.

Domus - https://domusgroup.com/

Please let us know if this avenue of enquiry proves fruitful, it would be interesting to know Colin’s thoughts on it.

 

[Bruce Watt]

The tiles are flat. I have tried the hot cold treatment and there is no change to be detected visually.

 

[Bruce Watt]

Does that mean you’ve consulted with
Walls & Floors, what was their take on the situation?

Wallandfloors were very helpful, they organized the Norcros tech guy to come out to view the issue. Please see first posting for their initial reply. The tech guy would not comment formally, his job was a fact-finding position only, so I was told, and I would have to wait for the formal lab tests. Apart from the issues stated in the first post which he did state was not the issue that caused the problem. However, when the report came through it was just reiteration of the tech guys informal site comments. There was nothing technical within the report or lab reports done that I was aware of. I was very disappointed with the Norcros report, it was very inconclusive with lots of 'could be the issue' suggestions. I believe Norcros probably know exactly what the issue is but refuse to state it as it might make them liable, but this is a guess. I can only draw a conclusion from how they have responded. I did respectfully reply to their report and they did not respond.

All I can say is like many people here I have never seen anything like this before and it is a shame I can not get a definitive conclusion to the issue.

Thank you all for your help

 

[Time's Ran Out]

With the photos that you’ve shown us, and I don’t think anyone on here can quite believe what we are seeing, IMHO it is certainly a tile issue!
No ceramic should bend like that so it must be a manufacturing issue and they are the people that need to do the tests and are liable.
TTA and name and shame if no conclusion drawn.
I can see this going further to your benefit.

 

[Waluigi]

Has it only happened on the outside wall?

 

[Bruce Watt]

With the photos that you’ve shown us, and I don’t think anyone on here can quite believe what we are seeing, IMHO it is certainly a tile issue!
No ceramic should bend like that so it must be a manufacturing issue and they are the people that need to do the tests and are liable.
TTA and name and shame if no conclusion drawn.
I can see this going further to your benefit.

Well, I have purchased the same tile again from the same supplier, ( so they must be confident it is not the tile, I assume) to redo the showers using a different tiler and adhesive. With the process of elimination, I will get closer to the problem.
I will report back once the showers are redone and let you know if the problem returns.

 

[Bruce Watt]

Has it only happened on the outside wall?

no. external and internal walls, masonry and timber stud walls. it makes no difference.

 

[widler]

Was the plaster dry? How hot is it in the house, ive seen plaster and render bulge internal with excessive heat and drying far too quick?

 

[Waluigi]

This is what I was thinking, very porous tiles, rapidset and a huge amount of shrinking.

Unlikely that it would happen so long after installation though IMO.

No idea. Baffling. It’s all just speculation on my part.

 

[Bruce Watt]

Was the plaster dry? How hot is it in the house, ive seen plaster and render bulge internal with excessive heat and drying far too quick?

It's a newly built house, everything was bone dry. It was tiled in the summer so just normal summer heat here in the UK. The tiles are not in direct sunlight.

 

[jobdone]

I have seen this before. The first time was a wall above a bath which backed on to the airing cupboard.
The paint was not removed (young and inexperienced) Weber rapid set was used.
The paint delaminated from the wall and left nothing for the adhesive to hold on to so it curled the tile. It was very bulged.
It did not appear to start for about 3 months. It started to be noted when the glaze cracked like a crackle glaze tile and continued until full desalination.
The adhesive was up to 7mm in the centre of the wall due to uneven plaster.

 

[jobdone]

The paint is the culprit here.

 

[Spud]

I think it is an under fired biscuit on the tile with a excessively thick bed of adhesive which has caused the tile to bend, the poor prep work ( mist coat) didn't help but didn't cause the tiles to bend in my opinion

 

[Bruce Watt]

I have seen this before. The first time was a wall above a bath which backed on to the airing cupboard.
The paint was not removed (young and inexperienced) Weber rapid set was used.
The paint delaminated from the wall and left nothing for the adhesive to hold on to so it curled the tile. It was very bulged.
It did not appear to start for about 3 months. It started to be noted when the glaze cracked like a crackle glaze tile and continued until full desalination.
The adhesive was up to 7mm in the centre of the wall due to uneven plaster.

Thank you Jobdone,
So the quick set adhesive shrinks as it dries. If it does not have anything to grip onto, it naturally shrinks on the none grip side creating the bulging effect. Thus, I think it must follow that the adhesive must grip onto the surface first before it shrinks. interesting! That does make some sense in explaining the situation. Thanks again to all.

 

[Tile Shop]

@Paul C. Could probably help..

Sorry Andy, just seen this so thanks for point it out. I'm amazed at how much the tile has bent without it breaking completely.

I haven't read the full thread in detail but have skimmed over it so apologies if I have simply repeated anyone.

Ok, so yes the paint was a very bad idea. But regards to the movement joints in the corner, although they should be siliconed, i don't think it would have made much difference. A tiny amount maybe, ultimately it still would have failed.

The main thing that Norcros would have been better off mentioning at the time..... As others have said about the depth of adhesive, the thicker it is the more shrinkage in rapid setting adhesives will occur. The Uniflex is a C2F and is only designed for a maximum 6mm final bed depth. Norcros say it can go to 10mm but only in small isolated areas. Based on the images it is 10mm (or more) everywhere. The only reason you would need to go that deep in one hit is if the wall was so far out of true of if there were dents that needed filling, but if that was the case, it would be best practice to correct the wall first before attempting to tile it and aim for a thinner 3mm full coverage.... unless you had an adhesive designed for much thicker beds.

Jobdone has hit the nail on the head as to why the curling happened, the adhesive gripped the paint, but the paint didn't grip the plaster. However at that increased depth bed, even with a correctly prepared surface, I would still put money on a class BIII lightweight ceramic tile cracking under the stress of the rapid adhesive shrinkage. A BIa porcelain tile may be able to withstand it far better and eventually settle but tile type alone would not be a reason for such a vast depth.

Unlikely the tile is faulty, it just has a very low biscuit density so could bend to some extent, but as I have never seen a tile bend like that in 20 years, I would be interested to find out how that happened without shattering into lots of small pieces.

 

[Bruce Watt]

Sorry Andy, just seen this so thanks for point it out. I'm amazed at how much the tile has bent without it breaking completely.

I haven't read the full thread in detail but have skimmed over it so apologies if I have simply repeated anyone.

Ok, so yes the paint was a very bad idea. But regards to the movement joints in the corner, although they should be siliconed, i don't think it would have made much difference. A tiny amount maybe, ultimately it still would have failed.

The main thing that Norcros would have been better off mentioning at the time..... As others have said about the depth of adhesive, the thicker it is the more shrinkage in rapid setting adhesives will occur. The Uniflex is a C2F and is only designed for a maximum 6mm final bed depth. Norcros say it can go to 10mm but only in small isolated areas. Based on the images it is 10mm (or more) everywhere. The only reason you would need to go that deep in one hit is if the wall was so far out of true of if there were dents that needed filling, but if that was the case, it would be best practice to correct the wall first before attempting to tile it and aim for a thinner 3mm full coverage.... unless you had an adhesive designed for much thicker beds.

Jobdone has hit the nail on the head as to why the curling happened, the adhesive gripped the paint, but the paint didn't grip the plaster. However at that increased depth bed, even with a correctly prepared surface, I would still put money on a class BIII lightweight ceramic tile cracking under the stress of the rapid adhesive shrinkage. A BIa porcelain tile may be able to withstand it far better and eventually settle but tile type alone would not be a reason for such a vast depth.

Unlikely the tile is faulty, it just has a very low biscuit density so could bend to some extent, but as I have never seen a tile bend like that in 20 years, I would be interested to find out how that happened without shattering into lots of small pieces.

The finish adhesive thickness is circa 7 to 8 mm. I understand the tiler is known for thick adhesive bedding.

The tile has bent far beyond that of normal. The adhesive is holding everything in place and when the tile cracks generally the adhesive does not until it gets to a point it can not, so the adhesive is bonding all the cracked tiles together. The whole wall of tiles is shattered and the adhesive is holding everything together.
Before the tile cracks, it is amazing to see the extent of how much bend/bulge the tile can withstand with the reinforcement of the adhesive stick to the back of the tile.

 

[Tile Shop]

Can you post some pics of the cracking/shattering?

 

[Bruce Watt]

Hello Paul,
The cracks are very fine and do not photo very well for you to be able to see.
However, I feel with all you helpful tilers out there, you may like to try this for your selves. Select a large-ish tile and apply 7mm plus of quick set adhesive to the tile back, do not apply to the wall. Put to one side somewhere and over the following weeks and month watch and see what happens. If the theory is correct you should be able to reproduce the effect.
I believe for weeks and even months later the effect does grow even when you think the adhesive is dry and set.