Large format popped around edges

[Gary Lee]

Hi guys I wonder if anybody can tell me what's gone wrong. We have laid a load of 1200sq porcelain tiles using the retailers recommend adhesive. The ufh was fired up a week later and temp was raised a couple of degrees per day and every tile has lifted around the edges. They are still stuck firm in the middle. We used the prolevel levelling system to help align the joints. It might be worth noting corex sheets were taped over the top fee a couple of weeks and locked a fair bit of moisture in. Before I approach our public liability company I'd like to know what's caused it. Thanks in advance.

 

[Time's Ran Out]

What was the substrate?
Any decoupling/crack mats used?
Adhesive type?
Adhesive bed depth?
Solid bed fixed or have the levelling clips pulled the edges up?

 

[Tile Shop]

how many square metres is "a load"?
how big are the grout joints?
Have you used expansion joints or left a perimeter joint?

 

[Tile Shop]

also, is the adhesive still stuck to the tiles, or the floor in the affected areas?

 

[Italy]

instead I want to know:
how big are the tiles and the thickness

 

[Gary Lee]

Hi thanks for the replies. They were laid over a flowing 40mm screed that had been down for two months as instructed by the company. No decoupling mats were used, the adhesive was norcros S1 standard set flexible Norcros Standard Set Flexible S1 Grey Tile Adhesive - Norcros Adhesives, trading division of Norcros Group (Holdings) - https://www.ribaproductselector.com/Product.aspx?ci=27063&pr=NorcrosAdhesives-NorcrosStandardSetFlexibleS1GreyTileAdhesive they were laid with a 10mm notched trowel and clips were used, there was a curve along the edges and most corners pulled when the clips were tightened. The room is 8mx8m and joints are 3mm and 10mm around the perimeter. I haven't lifted a tile yet as they are all still fixed in the centers. They are 1200mm X 1200mm x 12mm porcelain

 

[Waluigi]

‘A week later’

Too soon IMHO

 

[Tile Shop]

BS5385, part 3, C.2.4:
"Once the floor tiling is installed, the heating system should not be run for at least 10 days in order to allow the tile bedding to cur/dry thoroughly".

3 days too soon shouldn't make too much difference, but the cold temps we've had recently would drastically slow the curing process.

 

[Dumbo]

Did you back butter the tile , most on here would advocate using at least a 10mm trowel on the floor and a 6mm notch trowel on the tile with the ribs running in the same direction .

 

[Tile Shop]

Hi thanks for the replies. They were laid over a flowing 40mm screed that had been down for two months as instructed by the company. No decoupling mats were used, the adhesive was norcros S1 standard set flexible Norcros Standard Set Flexible S1 Grey Tile Adhesive - Norcros Adhesives, trading division of Norcros Group (Holdings) - https://www.ribaproductselector.com/Product.aspx?ci=27063&pr=NorcrosAdhesives-NorcrosStandardSetFlexibleS1GreyTileAdhesive they were laid with a 10mm notched trowel and clips were used, there was a curve along the edges and most corners pulled when the clips were tightened. The room is 8mx8m and joints are 3mm and 10mm around the perimeter. I haven't lifted a tile yet as they are all still fixed in the centers. They are 1200mm X 1200mm x 12mm porcelain

Laitence removed?
Primer used?

Still no mention of back buttering, so chances are you lifted the tile out of the adhesive. A 10mm serration on its own is insufficient on large format tiles.

 

[Time's Ran Out]

40mm poured screed!
Possibly a gypsum based screed with a standard set s1 adhesive!
Surprised if there is cover on a liability insurance for workmanship.

 

[Dumbo]

BS5385, part 3, C.2.4:
"Once the floor tiling is installed, the heating system should not be run for at least 10 days in order to allow the tile bedding to cur/dry thoroughly".

3 days too soon shouldn't make too much difference, but the cold temps we've had recently would drastically slow the curing process.

Maybe covering with the corded may have slowed the curing time also . So possible accumulation of factors there .

 

[Gary Lee]

The radiators were on in the house and it was fairly warm. The ufh was only opened up very slightly we didn't notice any warmth for the first few days. The backs of the tile were not back buttered which I first thought could be the problem although it wouldn't explain the edges only popping. I can't actually find a datasheet for the adhesive. It's not even listed on their website, I will email. The smaller cuts around the perimeter seem to have stuck well. Thanks for your help guys.

 

[Gary Lee]

Yeah the floor was pretty wet when we lifted the cordex. The tile shop recommended adhesive based on the floor screed spec and tiles they supplied. Could they have issued the wrong stuff. I have a feeling not buttering the back of the tile is possibly the problem here. Apparently my pl covers workmanship so my partner says but we'd rather not make a claim if possible. Willing to hold my hands up though. Laurence was fully removed and primer also recommended by the tile shop was used. I'll have to find out what it was .

 

[J Sid]

as TJ says, 40mm flow screed. Exactly what is this screed?

 

[Dumbo]

Was the heating commissioned prior to tiling

 

[Gary Lee]

It was anhydrite and the heating was commissioned beforehand

 

[J Sid]

what rh reading did you when tested?
was Laitence removed?
what was used for priming?

 

[J Sid]

sorry, you have answered the 2nd and 3rd questions

 

[Dumbo]

Did you do a moisture test on the screed prior to tiling

 

[Time's Ran Out]

Ok me too!
Did you do a moisture test on the screed and what was it’s RH reading?

 

[Gary Lee]

Yes laitence was removed. This is the primer we used.

 

[Waluigi]

Usually the tiler says which adhesive to use and knows which primer was used before the question has been asked.

 

[Gary Lee]

We didn't take a reading but it was a good 60 days on a 40mm screed

 

[Gary Lee]

I didn't do the tiling myself I'm just trying to get to the bottom of it.

 

[Old Mod]

Who are you then, the client or contractor?

 

[Old Mod]

60 days is in no way a guarantee that the screed is ready for Tiling.
Was it force dried with ufh?
How many coats of primer were used and to what dilution?
Tiling an anhydride screed with cementitious adhesive requires an in-depth knowledge, and is not something to be taken lightly.
Sounds like tile supplier needs to do more research.

 

[Old Mod]

I’m in no way suggesting that it’s all the fault of the supplier either.
The tiler could be just as much at fault.
The installation technique isn’t going to win any awards either.
If these are 12mm pieces, how can you tell they’ve de-bonded around the tile perimeter exactly?
Sorry if it seems a dumb question, it’s not something I’ve come across before, only lifting around edges.
What first alerted you to it, how did it present?
Are you saying the tile itself was con-caved or
con-vexed?
If they were con-caved, installation techniques would have added to the problem for sure, as well as less than favourable materials, it wouldn’t have made this a standard install.

With the industry moving more and more in the direction of extra large format tiles, a lot more education needs to take place, and that applies to right across the building industry, not just installers.
And retailers need to get their act together too, just selling this stuff isn’t good enough any more.

 

[Bill]

Need photos of this phenomenon ......not seen anything like as described so it could be that the description is wrong.

 

[Gary Lee]

I'm the contractor. We can tell because we removed the grout on a couple and tried to lift them and they were stuck fast. I'm not really trying to point the finger at the supplier I just don't want it to happen again. And for the reason you mentioned above I would assume we will be fitting a lot more of this type of floor in the future. They were concaved a level would rock over the edges. All tiles were the same. I first noticed couple of joints cracking but now they are terrible and it seems some of the tiles have straightened out when I put a level across them. That's impossible for a porcelain tile to do right?