Porcelain Tiles come away from Adhesive after 7 years

Hey guys, first time poster so be kind!

I had some porcelain tiles fitted in 2012, in the conservatory with underfloor heating. The same tiles have been laid throughout the ground floor of the property.

Recently, myself and my wife noticed a hollow sound when our daughter threw a tennis ball across the living area (open plan) through to the conservatory, we noticed a definite difference in the sound of the bounce when it got towards the conservatory. Typically the floor in that area has always been solid and this was new.

Upon recalling the tiler, he confirmed after lifting one or two of the tiles, that the tiles were pressured inwards and thus causing them to bow upwards. He first reaction was "that's, there's ground movement" - the reality is there has been no noticeable ground movement in the building outside of the norm, ie. there really hasn't been any that isn't usually tolerable as there are no cracks or signs of substance anywhere.

Upon lifting the few tiles to relive the bowing pressure, the cracking in the adhesive seems to be fairly consistent throughout. The tiler informed me that the process used to lay the tiles (which we luckily photographed at the time in 2012) shows the professional approach our tiler used to ensure the ground work for the UFH, boards and leveller all went on in accordance with the UFH mesh used then adhesive applied on top. Upon initial fitting, we adhered to the guidance of not switching it on for the first few weeks whilst it was still setting, it was switched on during the installation to ensure power and the heating mesh was working as expected. In summery, the Tiles are loose from the adhesive, but the boards are solid to the ground with no give unless you take a hammer to it. The adhesive is brittle and loose and comes away easily.

Below are some pictures that show the cracking in the adhesive. The tile came away quite easily from the centre of the conservatory-room where the main hollowness and bowing seems to be apparent. The few images after show how the tiles were laid with the UFH at the time.

I'm just an average consumer, any help in this situation would be very appreciated. Any feedback from the images would be great, the ones that show the laying process are ones from 2012 and the ones that show the cracking are from last month.

Loose Tiles:


Laying Process

1) it doesn’t look as though he back skimmed the tiles.
2) adhesive has cracked when drying, possibly UFH turned on too quick .
3) cant see any expansion joint between lounge to conservatory floor.

timeless john said:

1) it doesn’t look as though he back skimmed the tiles.
2) adhesive has cracked when drying, possibly UFH turned on too quick .
3) cant see any expansion joint between lounge to conservatory floor.

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Thank you for the quick response. It's nice to have another professionals view. He hasn't said it maybe down to him, but I also trust him (foolishly maybe) but the rest of the work around the house has been top class. Maybe I should ask him about the points you raised.

Thanks for your speedy feedback.

I also agree with @timeless john . No back skimming I would consider as the biggest issue . You don't need to turn heat to test its working this can be done with a multimeterto test continuity .
Also I would of put a levelling compound over the ufh before tiling but that is a personal preference .

What adhesive was used...???

Classic example of thermal shock in my opinion. Heating gone from cold to hot too quickly .perhaps not at the initial stage but somewhere down the line

Localtiler said:

Classic example of thermal shock in my opinion. Heating gone from cold to hot too quickly .perhaps not at the initial stage but somewhere down the line

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Just looked again and have to agree

Andy Allen said:

What adhesive was used...???

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I believe it was Arditex. I have copied the materials from the original receipt if it helps?

Localtiler said:

Classic example of thermal shock in my opinion. Heating gone from cold to hot too quickly .perhaps not at the initial stage but somewhere down the line

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Not heard of this one before. Interesting. I’ll look in to it. The conservatory area does get colder than a normal room would in winter conditions. But this UFH would usually heat up the whole area very nicely.

Localtiler said:

Classic example of thermal shock in my opinion. Heating gone from cold to hot too quickly .perhaps not at the initial stage but somewhere down the line

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Must agree Thermal shock can happen at any time but no skim to back of tile and no expansion joints as @timeless john says wont
have helped

If the adhesive was XR7, it has a short pot life. Is it possible more water has been added to a setting mix to extend pot life? Causing weaker adhesion...( or skinned over to early) The adhesive also looks thick, I can't see on the spec sheet the maximum bed thickness, generally max 10mm. With a brick bond setout, excessive packing up may have happened to get tiles flush???

It's rare but some tiles are contaminated on the backs if you have a box spare you could check this and eliminate this as a cause.

According to the original receipt,it's showing there are 5 bags & bottles of Arditex which is a levelling screed on it to encapsulate the UFH , maybe should have also used anti-fracture mat over the levelling screed as well

Agree with what others have said. When you say it was turned on during installation , I hope this wasn’t after the tiles were started to be laid? ......the job looks a bit rough too. Laying the Matt before the insulation boards adhesive has fully set, overlapping the heat Matt, heat Matt too close to the perimeter.

ardex give a 10 year guarantee contact them. most tilers will give you a 2 to 5 year guarantee.

Could go there but wouldn't be surprised if the came back with it's not our problem ,it's an installation problem again playing devil's advocate?