UFH tiling problem - Tile Advice

[Jokerit]

Hi everyone I need some advice from the collective mind.
I've tiled a kitchen floor which has water UFH the tiles were 30 so metres of 1200x600 porcelain the adhesive was single part flexible rapid, grout is bal flexable grout i also fitted idrobuild anticrack matting i used a 15mm notched trowel and buttered each tile prior to laying. Now comes the problem 2 tiles cracked both tiles were check outs at different corners of the room. I replaced those tiles and 2 weeks later same thing has happened again same tiles I replaced previously plus one more around the island again another check out. Also customer is saying the grout has cracked all over the floor. To be honest I'm at a loss as to why this is happening its obviously something to do with expansion from the UFH but I've not had this happen before and I've been a tiler for 38 years. Customer is looking for answers to why its happening and I have none so any thoughts you may have would be welcome

 

[Dave]

Hi.
how tight are the L cuts to the wall etc. ?
grout cracking .. was the heating commissioned properly after tiling. ?

 

[Jokerit]

Hi.
how tight are the L cuts to the wall etc. ?
grout cracking .. was the heating commissioned properly after tiling. ?

Let a 2 mm gap to door frame and filled with silicone to match grout colour and the skirting hasn't been fitted so good gap to the wall. I think your right to assume the heating wasn't commissioned right but their saying it was but I have my doubts it my word against theirs

 

[Dannyl]

Hi, i am recently having the same problem,and also a first for me after 15 years of tiling, i tiled a 60m2 floor over ufh ans sand cement screed, mapetex de coupling, 12mm trowel and back buttered tile too, 6 days later the floor was grouted and i had zero concern that i would be called back, 5 weeks after underfloor heating had been on i now have a de-bonded floor, i took a tile up and found pools of water and the smell of damp, client is now taking legal action saying i should have tested the screed, although i did but only using a moisture meter, results were low at 7 to 9% prior to tiling, am i at fault? Totally stressed at the moment😅

 

[Dave]

Hi, i am recently having the same problem,and also a first for me after 15 years of tiling, i tiled a 60m2 floor over ufh ans sand cement screed, mapetex de coupling, 12mm trowel and back buttered tile too, 6 days later the floor was grouted and i had zero concern that i would be called back, 5 weeks after underfloor heating had been on i now have a de-bonded floor, i took a tile up and found pools of water and the smell of damp, client is now taking legal action saying i should have tested the screed, although i did but only using a moisture meter, results were low at 7 to 9% prior to tiling, am i at fault? Totally stressed at the moment😅

How long had the screed been down ?

 

[Ajax123]

Hi, i am recently having the same problem,and also a first for me after 15 years of tiling, i tiled a 60m2 floor over ufh ans sand cement screed, mapetex de coupling, 12mm trowel and back buttered tile too, 6 days later the floor was grouted and i had zero concern that i would be called back, 5 weeks after underfloor heating had been on i now have a de-bonded floor, i took a tile up and found pools of water and the smell of damp, client is now taking legal action saying i should have tested the screed, although i did but only using a moisture meter, results were low at 7 to 9% prior to tiling, am i at fault? Totally stressed at the moment😅

Always a tricky one. The standards generally say that moisture resting should be carried out but not who should do it. That said as an "expert" you should be able to offer advice. That you tested it is to your credit. That you went ahead at 7% is debatable in its wisdom as sand cement screed should be below about 3% or 4% to be dry. 60m2 in one single bay us too big and you dont mention movement joints. If there were pools of water and a damp smell it does not sound like a damp screed but something more significant like a leaking pipe or two. If you want to fight the court action you need expert technical advice however based purely in your limited description it's likely you are at fault.