Help!: A big flooring problem!

[hpandlou]

Hello - apologies from a complete techno-phobe, so if this is in the wrong place, please advise! This is also my first visit and I am hoping someone may be able to give some much-needed advise!

As part of a kitchen extension (5mx4m), a new concrete floor slab was laid by a builder at the beginning of last year, with all requisite insulations etc. Piped water underfloor heating was installed to manufacturer's instructions and my plasterer/screeder recommended a floor screed with fibres to improve strength etc. This came pre-mixed in August and was duly laid to a depth of 65mm. Screed was left to dry and u/f heating was gradually turned on after approx 5 weeks - as we were recommended - to a max room temperature of 18 degrees. Tiler - highly recommended by a number of trades and shops as being 'the one you have to have' - came to lay the floor in mid-October. He was unhappy with the number of small hairline cracks in the surface of the screed and recommended we use 'Ditri matting' (spelling could be completely wrong!) so that tiles etc would not be affected by ant movement of the floor slab/screed. We followed advise and it was stuck down with appropriate adhesive and left 24hours to dry. Then he laid Brazilian slate tiles - 60x60x1cm - using a flexible adhesive and grout. Each tile was brushed/wiped on the reverse and seemed to be properly bedded down. Expansion gaps were left at all edged. U/F heating was not turned on until floor had been down for 4 weeks, and then turned on gradually again.

The floor appeared absolutely perfect and then, just after New Year, (so floor laid for 2.5 months approx), I noticed a slight noise when we stepped on just one tile and only when we stepped on a particular spot. I just assumed it was loose - no evidence of grout cracking or anything. Phoned tiler who was due to come back to attach slate skirting board, who was very surprised at the prospect of a loose tile but promised to look/sort etc. When he came one week later, 2 more tiles were noisy - a creak/snap/crunch/pop - but still no evidence of cracking. This week, half the floor is noisy, there is very small hairline cracks in the grout all over, and some tiles are very noisy. Most also sound hollow when tapped. The tiler thinks the screed has blown - I'm wondering if the adhesive has failed?

Any thoughts would be so welcome - apologies that I appear to have rambled!

Many thanks!
hpandlou

[Sir Ramic]

Do you know the name of the screed, Andryhite, Gyvlon or a sand and cement screed.

[Alberta Stone]

Sounds unusual given the ditra install.
Without detailed pictures it will be difficult to say more.
if a tile is loose then it would be prudent to pull it up and take some pictures close up of the back of the tile beside the spot it comes from.
But don't clean it before you snap the shot as that is part of what needs to be seen.

If the ditra mat is also loose then use a sharp knife to cut the square of matting out and take a shot of the condition of the screed surface as well.

Again, shots as you go with no clean up of the debris.

[doug boardley]

do you know if tiler back skimmed/buttered the tiles as well as spreading adhesive on the ditra?

[hpandlou]

Thank you for the response! As far as I know, it was a sand and cement screed with fibres - plasterer is coming this evening to have a look, so he may have something else to add!

[hpandlou]

Thank you! I'm sure that's going to be the next task, to actually pull up a tile, although at the moment, none are popping up or completely free. I think that would have to be done by the tiler as well, perhaps with my plasterer here.

[hpandlou]

In all honesty, I don't know - I did see him spread adhesive on the ditra with a trowel, but didn't take that much notice. It wasn't a quick, rush job - the guy has been tiling for over 30 years, and it took 7 days to prepare and lay/grout/finish the floor! I will see if I can find out and let you know - thank you!

[Max@ableskills]

If ditra had NOT been used i would have said that the tiles had uncoupled from the screed. It could be that the ditra has uncoupled from the screed. As doug says do you know if the tiles were back skimmed.

[Sir Ramic]

Are you sure it was Ditra tooo, Can you remember the colour ?

[hpandlou]

I don't know, unfortunately, I can only ask! I shall keep posting the updates!
Thank you

[hpandlou]

As far as I'm aware, it was - it was bought direct from a trade supplier - although I can't get hold of my husband to confirm at the moment! It's yellow - I was told by the tiler it can be blue or yellow - I can see it at the threshold to the next room where we haven't yet sorted a cover!
Thank you

[Scott]

Was the screed primed prior to the mat going down?

[Sir Ramic]

If its Yellow it could be Dural.

[hpandlou]

I don't honestly know because I was at work - I know we had to pay an extra £70 for specialist adhesive and it's a matting the tiler has worked with many times before. In fact, if we hadn't taken his advise and used it, I think we would have been asked to sign a disclaimer. It was left 24 hours for the adhesive to dry - don't know any more than that at this stage!

[Sir Ramic]

I don't honestly know because I was at work - I know we had to pay an extra £70 for specialist adhesive and it's a matting the tiler has worked with many times before. In fact, if we hadn't taken his advise and used it, I think we would have been asked to sign a disclaimer. It was left 24 hours for the adhesive to dry - don't know any more than that at this stage!

Ahhh now you see we would need to know what this special adhesive was as when I lay Ditra or similar I use single part flexible tile adhesive .

[timeless john]

Great thread - and intriging.
Ditra is bright ORANGE.
Special adhesive!
Everything sems OK but ..........tiles are loose.

[hpandlou]

Husband just walked in! It is Dural and was stuck with Topps' single part flexible as you suggest - could be rapid set!
Thank you

[mikethetile]

Like Tj im intrigued by this as everything seems to be done correct even down to the selection of tiling contractor

[hpandlou]

Thanks for all the replies. Should we have used a 2-part flexible adhesive?

[doug boardley]

a one part flexi is fine, well it's what I use anyway!

[Sir Ramic]

a one part flexi is fine, well it's what I use anyway!

Same here.
So now we need to know if tiles are debonded from Dural or Dural from the floor....unless I have missed that part.

[hpandlou]

Thank you to everyone who has posted so far - having spent a lot of money and taken every bit of advice given, all I want to do is get the floor right again and make sure the problem isn't repeated. Plasterer coming at 7.45am to do some kind of 'density test' for screed, and we will take it from there. I shall post any findings tomorrow if I can!
Thank you!

[Scott]

At least you are in the hands of a competent tiler who has from the information given, followed the correct methods and procedures.
Unfortunately for him and yourselves its failed in this instance.

[hpandlou]

Unfortunately, it seems so - just not looking forward to all the upheaval - again - that looks as though may be coming! Onward and upward I shall post any further news as I have it - thank you.

[Brinkley]

was the floor dusty . was it primed adhesive will stick to dust andnot bond to the floor

[TF Ed]

tiles lose there grip by either movememt or lose/insufficient bond.

the floor was laid early 2010? then tiled october 2010? i think scottley is barking up the right tree regarding sealing the floor.

thats a long time to leave the floor prior to tiling (ie to dry out), especially after the ufh had been commisioned..i personally think that the dural/ditra has lost its bond in places causing loose areas. this has caused hollow spots and the tile/tiles have been able to move up and down when walked upon and eventually debonded where the ditra has lost its grip to the screed.

thats the only thing i can think of unless alan (ajax) can read this and give his opinion on the fibers used in the screed. although fibers strengthen, if they allow no movement, then the screed can stress.

thats the best i can offer on this given the info provided
ed

[Phil Hobson]

As above I am totally confused everything seems to have been done correctly, Dural is a good product imo. I will be very interested to know if the tiles have de-bonded or the mat?

[hpandlou]

Floor was dusty, but I think it was cleaned/primed before adhesive used - I don't know for sure, but tiler and I have talked about the need to prime different surfaces, eg. slab when screed is laid, so I am making an assumption.
Thank you

[Dave]

Hi..

Can i ask was this screed laid as one piece or was it tied into an original floor area. and were the tiles over the old and new areas..?..

So what i mean is this 2 separate floors.. old and new.. or just one new floor area.

[hpandlou]

One new floor area - the floor slab was laid in 2 'hits', but the screed was laid over the 2 at the same time. The loose tiles are all over.
Thank you