Newbie looking for advice on tiles lifting!

[Benc]

Hi all, I’m new to this and tiling! Looking for advice!
Basically we built a 30sqm extension on our house to move the kitchen into it so we could have a larger living space,
It was recommended to use underfloor heating in the extension and a cement based liquid screed! (Rest of the house is heated by rads)
We went for 1.2m x .600m porcelain tiles!
The floor between the house and the extension wasn’t level being the extension was a bit lower than the original floor!
Anyway got our tiler organized and he told us the floor needed sealed with a primer and that the underfloor heating should be on for two weeks an off for at least a week before he started! All this was done!
Tiler started and when he was finished we where well impressed with his work!
Three weeks later when the new kitchen was being fitted they noticed a loose tile and the tiler blamed the type of screed! All the tiles in or 30sqm meter extension are loose but the rest of the house is fine! The ufh was switched back on 10 days after it was tiled at a low level! Will upload a few pictures so can can get advice on what we need to do to solve the problem!! Thank you ben

 

[Italy]

you have to tell the tiler to change the job,
better if it goes to sell ice cream

 

[WetSaw]

Tiles that size need a perfectly prepared substrate. Are you sure the screed is cement based? Clearly the adhesive hasn't bonded to the substrate, whether that is because of the wrong primer being used or the screed needing sanding before.
How long has the screed been down and how thick is it?
The floor should also have been levelled before tiling rather than trying to make up the depth with big blobs of adhesive.

 

[hmtiling]

Wet screed, possibly gypsum based. They're is no fix unfortunately. The job needs doing from scratch by someone who knows what they're doing and has testing equipment

 

[Andy Rhodes]

shocking, no anti-fracture matting used but don't think it would have made a difference, might as well not used the notched trowel with the number of adhesive spots on the back of the tile. What did they prime the floor with PVA or acrylic based?
You defo need to get them back to redo the floor at a cost to themselves

 

[Qwerty]

Looks like a full rip out required

 

[Benc]

It’s definitely a cement based screed and no instructions from the supplier of the screed or the pourer to sand the floor! It was primed with a pva sealer! Far as I know all the tiles are buttered on the back an then dot an dabbed! Yeah all the tiles have to come up and be re done but what’s all your thoughts to why this has happened? Is it the dot an dabbed??

 

[Benc]

The cement liquid screed is 50mm thick and was poured in 6 months ago!

 

[J Sid]

pva...... Really?

 

[Benc]

Should the pva not have been used on the liquid screed?