First problem in 10 years....

[Danj]

Hi all,

I'm new to the forum but ive been tiled for around 12 years with no major problems until today.......happy new year ‍♂️

So I finished laiding a floor on the 4th of December 40m2 in total, 32m2 onto a new concrete screed (not slurry screed) with piped Ufh and 8m2 onto existing contrete with no Ufh.

I do a lot of work for the builder and was assured the floor was dry.....

Over the Xmas break I saw a few other trades out and about, they told me some of tiles are loose and that the Ufh was turned on around 2 weeks after I finished. I always recommend 3 weeks. I've been to investigate this morning and the 32m2 onto fresh concrete is loose yet the 8m2 on existing is solid.....

Just curious to know if anyone has any other suggestions as to why they could be loose before I start rowing with the builder. As I said I've been tiling for 12 years with no problem, I used ultra primer and extended set flexible adhesive and grout.

Many thanks

 

[LM]

Hi Danj
Was the Ufh commissioned correctly before you tiled it?
Was it turned on at the correct rate and time after you tiled it?
What type of tiles and adhesive were used?
Has there been exspainsion joints factored into the floor and perimeter?

 

[Danj]

Hi lee,

The Ufh was tested before tiling yes.
Not sure on the rate at which the temperature was raised, I'm meeting the builder tomorrow to get more details.

The tiles are 600x600 porcelain I used ultra pro extended set flexible adhesive.

There are no expansion joints as the room is 8m at maximum length and 5/10mm parimeter. There arnt any raised areas only hollow sounding tiles over the heated areas.

Thanks for the reply

 

[Rookery]

Did you back butter the tiles?

 

[radim]

Lift a tile and see what is debonding - adhesive from concrete or adhesive from tile as it might be sign of too high temperature of UFH

 

[Danj]

I back skimmed them but find it too much of a coincidence that the un heated areas are fine.

 

[ttt tiling]

Last time this happened to me , the screed had failed .
Bi house in London , 100000 pound kitchen on top of 40m2 Travertine 40x20's . Turned out the customer had ramped up the underfloor heating until the floor was hot , she was happy then , not so happy when the floor cracked up.
During a meeting with the architect , the builder and my mate Allan Berks from Fired Earth , we took a tile up and a lump of screed came up with tie and adhesive attached to it > never did hear what happened , but we got paid .
Hopefully you'll find the same thing

 

[Flintstone]

See if there is any moisture when you lift a tile, that will tell you a lot. If the builder has ensured you it's dry and tile it then I would be pointing the finger at him. Also if you didn't specifically instruct the customer how and when to put the heating on, they will have ramped it up I'm sure.

 

[Chalker]

Looks to me like the screed wasn't dry. Never take the work of a builder. Always test. Even a full tin of paint with a price of polythene underneath, left overnight will tell you a lot. Builders will tell you it's tested. Thus can just mean it has been pressure tested! It needs to be heated before tiling.

 

[Flintstone]

Often to a builder if it's set it's ready to tile

 

[Danj]

The job was a rush from start to finish to be fair so I wouldn't be surprised if the concrete hadn't cured properly although I did think it would take more than 2 weeks for them to pop. The builder is the only one who's played with the thermostat as the customers haven't moved in yet......nightmare situation

 

[Danj]

Thank you all for your input, much appreciated

 

[LM]

You'll know a lot more once you've lifted a tile. Take a few pictures of the lifted tiles and the screed for us. Don't over commit yourself with anything you say to the builder until you've had time to consider the findings.
It would be helpful if the builder is honest about the timing of turning on the Ufh and at what rate. Another possibility could be a faulty thermostat in the floor, I've seen floors fail due to this also.

 

[Old Mod]

the builder is honest

Don't want to diminish the severity of this thread,
But I don't think I've seen both those words in a sentence before!

 

[LM]

Don't want to diminish the severity of this thread,
But I don't think I've seen both those words in a sentence before!

lol, he's known him for 12 years so he should be able to get a sense if his telling porkies and then that might indicate a bit better as to what happened.

 

[Old Mod]

known him for 12 years

You sure Lee?

Sounds like working out why it failed will only take as long as it does to lift a tile.

 

[hmtiling]

i'd be surprised if it's anything other than a wet screed.

 

[J Sid]

could be a multitude of reasons from wet screed to adhesive manufacture problem to incorrect heat up. Until the OP has lifted a tile to see what's happen, no point guessing imho.
I've had one fail due to adhesive manufacture fault, one due to builder turning the to max from cold and the last job of the year, which looks like it is ok but thought it would fail due to the sparks wiring the thermostat by the front door (cold area due to workers in and out, so asking for more heat) to two of the three pipe circuits in the lounge. 2/3 of the floor was 29 degrees and 1/3 was 17 degrees, plumber and electrician both saying all is fine.

so I would say a full investigation is need and don't take the word of anyone.

 

[Danj]

Ok so I've removed the tiles to find dark patches and water literally running off the underside of the tile. I'm presuming this can only indicate too much moisture in the screed......

 

[Danj]

The majority of the adhesive has come up with the tile not stayed bonded to the floor

 

[Bill]

Ok so I've removed the tiles to find dark patches and water literally running off the underside of the tile. I'm presuming this can only indicate too much moisture in the screed......

Are you sure the heating pipes aren't leaking?

 

[LM]

Sounds like too much moisture in the screed then. The Ufh may have been pressure tested but it doesn't sound like it's been commissioned.

 

[Flintstone]

sounds like the screed was no where near dry!
Have you confirmed it's not anhydrite as well?

 

[Danj]

Definitely concrete, when I say dark patches.....it's not wet just darker shades of grey. I'm convinced it was too green

 

[Flintstone]

If it's soaking wet under the tiles all over, the screed wasn't dry simple as that!

 

[hmtiling]

i'd be surprised if it's anything other than a wet screed.

Ahem

 

[Danj]

Yeah it's looking that way, I just wanted to put it out there see if there was anything else that could cause it as I do have a good relationship with the builder. Now I just need to find an extra 4 days.......as normal.......

 

[Danj]

Thanks again for all the replies, this is the first time I've ever done this......great experience

 

[Danj]

Time to buy a moisture meter.....any advice?

 

[spooner68]

I've always put the guidelines for drying times and how to commission UFH into my quote so its in black and white. As the years have gone by this has become a standard (lengthy) paragraph but on the 2 occasions there have been problems I've found that either the screed hadn't been left to dry long enough or the UFH had just been cranked up to 11 from the off.
I always get the client to put a piece of polythene down under a brick/tin of paint/tile overnight to do a rule of thumb check. Have had to postpone a few times as it was still wet mind!
There's a lot said about decouplers but I have never seen the need on a concrete screed. Thoughts?