Porcelain floor tiles direct to screed on wet UFH without DITRA

Hi Guys,

I had my kitchen floor tiled a few weeks back. The floor is a screed slab of approx. 24m2 over wet UFH pipes clipped to Celotex.

This screed was “hand mixed” vs ready mixed off of a truck and laid around 100 days ago of a thickness of 60mm.

Around 45 days ago the UFH was commissioned and set on a low heat and slowly cranked up and has been running on a stat since then. The screed did not crack in any places and the screed itself remains extremely strong and hard wearing.

The UFH was switched off a few days before tiling commenced so the slab was “room temp”.

So the tiler came in the morning, hoovered the screed, primed, then laid the porcelain tiles using BAL one flex adhesive directly onto the screed without the use of a decoupling matting. Tiles were laid on a full bed of adhesive (I don’t believe they were back buttered), Mapai colur plus grout was used – at this time I thought nothing of it.

So its 2 week roughly since they were laid – great job in terms of cuts, neatness and they feel solid under foot.

Before I switch the UFH back on I thought I would do a bit of research on the best practice method with turning it back on when I stumbled across some info which says that a DITRA/Decupling membrane should be used in these circumstances to better insure the tiles don’t crack/pop up.

I spoke with the tiler to get his opinion on it, and he said that it will be fine as long as I slowly crank up the UFH to running temp over the next week or so as per guide lines. He said he has used a good flexible adhesive and we are using porcelain tiles and that no cracks in the screed before starting and definitely dried out fully, so if any cracks were going to form, they would have by now. He said that he would only ever ditra UFH screed if the customer was using natural stone as this can be prone to cracking due to the natural lines in the stone itself are prone to cracking.

Clearly nothing can be done about it now other than wait and see and to be honest this post is pretty pointless :relaxed:- however I’m a little nervy about switching UFH back on.

What’s the verdict on this matter with the pros on this forum? Likely going to be fine or more likely to fail in the months/years ahead?

FWIW my UFH water temp does not need to be much more than 40 to 45 degrees to sufficiently warm the room, so the actual heat of the floor under foot is subtle.
 
I agree with your tiler. No uncoupling necessary. It does no harm to use it but all things being equal theres no need.
 
only putting your heating on will tell.
i personally would of used ditra like a similar job to yours i started today.
whats the tilers guarentee.?
 
Also any future failure cannot simply be attributed to the lack of Ditra as there are so many other things that can happen to a floor to cause tiles to fail.
 
Cheers gents, has put my mind at ease at least for now.

I guess if i had an option to do it again i would take the belts and braces option and have DITRA laid. i mean for the amount i have paid for the floor, tiles and agro if it would have ever needed to be pulled up again could be justified in my circumstances.

anyhoo its done now, fingers crossed and i guess time will tell
 
it seems to me your still not happy with your tiler for not fitting a decoupling mat, even though he has saved you hundreds of pounds, you can't win with some customers!

im not saying i am unhappy with my tiler... im simply saying i might have preferred to lay ditra for extra peace of mind to better handle any movement or cracks that may (or may not) develop over the months/years ahead is all.

@RayTheTiler has said he would have suggested to us Ditra if it was his job so im not sure as to how you think what i said was unreasonable.

That said with all the feedback i have got from the pros to my thread has put my mind at ease and i am appreciative for the input.
 
I'd rather have customers like you that are open and willing to these products than the ones that are not wanting to spend it when they are actually required.

As for screwing folk out of money is it really a screw over when the mat is physically there and the labour has been provided to install it? What have they been screwed out over? Hardly a great money making scheme installing a mat. Isn't a great earner for me anyway 🤷‍♂️
 
I'd rather have customers like you that are open and willing to these products than the ones that are not wanting to spend it when they are actually required.

As for screwing folk out of money is it really a screw over when the mat is physically there and the labour has been provided to install it? What have they been screwed out over? Hardly a great money making scheme installing a mat. Isn't a great earner for me anyway 🤷‍♂️
Very good earner for me 😃
 
I've just fitted mat supplied by the customer , adhesive supplied by customer , £5 psm labour , not really going to be bothering Rothschild any time soon . But I believe in belt a braces approach .
 
I'd rather have customers like you that are open and willing to these products than the ones that are not wanting to spend it when they are actually required.

As for screwing folk out of money is it really a screw over when the mat is physically there and the labour has been provided to install it? What have they been screwed out over? Hardly a great money making scheme installing a mat. Isn't a great earner for me anyway 🤷‍♂️
bit it isn't needed, in this situation is it...?
99% of tilers on this thread have said it isn't needed, or are they all wrong..?
if your on about different makes of tiles, then this isn't what this thread is about, is it.
some tilers do screw customers over using ditra with PORCELAIN TILES when it's not necessary.
and it's not just the fitting cost, you have the cost of the mat, and the adhesive, you may not make much out of it but the customer is still getting screwed for the extra cost.
 
No it isn't NEEDED with the PORCELAIN TILES however i'd class being screwed over as being charged for something that isn't there or hadn't been done, or at an inflated price even, the mat is still physically there. The customer said in passing he would have still have perhaps liked the mat now he knows about it and still got jumped on about money saving, it's just the flip side we get when trying to tell people to use mat, for the sake of helping prevent any issues it will only be x amount to help protect your tiles, it's now just the customer saying it and now us.

In this exact situation i didn't say it was needed nor did i say everyone was wrong, if like in this situation ( albeit hindsight now) the customer had suggested he wanted matting before i'd still happily fit it not thinking i was screwing them over because its not needed with PORCELAIN TILES, they aren't being screwed when it's something they have given the option to pay for and chosen it. That's my point
 
I'd be interested to know if the customer would still want it and be happy to pay the £25 to £30 m2 extra
 
The op here has already said in hindsight he would have fitted it for belts and braces approach, i'm just assuming they looked at the product and seen the cost of it and it wasn't an issue to them.
 
Sounds like the tiler did the right thing. My only question would be on incorporated movement joints across the floor. Was this done, as if not, a heated floor can certainly cause fractures?
 
Only a couple of small things I would’ve done extra ..
Your tiler didn’t seem to sand the floor with a square buff sander ( hire shop )to take off the residue (scum) that tends to happen on curing with a lot of liquid screeds with UFH or after vacuuming I would have washed it with clean water to remove any dust the vacuum didn’t get , allowed to dry and then prime ...
Turn that heat on gently and ..
Hopefully you don’t have any problems with it
 
Only a couple of small things I would’ve done extra ..
Your tiler didn’t seem to sand the floor with a square buff sander ( hire shop )to take off the residue (scum) that tends to happen on curing with a lot of liquid screeds with UFH or after vacuuming I would have washed it with clean water to remove any dust the vacuum didn’t get , allowed to dry and then prime ...
Turn that heat on gently and ..
Hopefully you don’t have any problems with it
Never heard of a "square buff sander". Is that special?
 

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