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?

 

[Albert]

You should not use pva on any screed that is to be tiled

 

[Old Mod]

The colours on your images are not very clear, it’s hard to distinguish between them.
The fact that the floor is immaculate and all the adhesive is stuck to the tile would suggest improper preparation.
Is there a thin layer on the adhesive that is a similar colour to the floor?
As if the adhesive has pulled a thin film of the floor up?
Your floor may have been down 6 months but was the house water tight when it went in?
I know how agreeable the weather can be there. 😀
Were your patio/bi-folds doors fitted, or was the back maybe sheeted out instead?
There is no guarantee it was dry, it should have been tested for moisture.
And yes PVA primer is completely incorrect as a primer for your floor.
Use the primer stated on the back of the adhesive bag, that’s why the info is on there.
And yes it does matter, if only to ensure your product guarantees remain in tact.
Was your floor sanded before the floor install?
Even liquid cement floors can need laitance removal first.

 

[Benc]

Yes it looks as if it had pulled a thin layer off the floor alright, I’m not sure why they used pva sealer on the floor! The house was 100% weather tight! All new windows and doors had been in place long before the screed had been poured! No preparation was done on the floor apart from being sealed!
The tiles all have to come up but does anyone know the proper procedure now to stop this happening again! The tiler doesn’t seem to think the floor needs sanded

 

[Andy Rhodes]

If that's was the case and your tiler did no prep work the 5 P's motto comes to my mind, poor preparation **** poor performance

 

[Tile Fix Direct]

You mentioned the tiler had back buttered the tile (good) but then laid onto dot and dabs (bad). The tiler should have achieved 100% adhesive coverage to the floor, but the image shown shoes a coverage of about 60%. A professional tiler would not lay these tiles using the dot and dab method, irrespective of back buttering the tiles. However, the way the 'dabs' have lifted cleanly is suspicious. Triple check the floor is not gypsum/anhydrite. Suggest you use a de-coupling membrane next time such as the new BAL Flexbone 2 Easy;
BAL Flexbone 2Easy Matting - https://www.tilefixdirect.com/product/BAFBONE-2EASY

 

[Old Mod]

The tiler doesn’t seem to think the floor needs sanded

Well to be honest, can you trust his judgement?
And “doesn’t seem to think” is exactly the definitive answer you require.

I’ve recently laid over 100m2 of 120 x 120 x 6mm thin tile on to a liquid cement based screed, and all the information supplied stated laitance free, and does not need sanding.

Un-sanded.


The darker patches are surface laitance, you can not adhere to this, it will separate at some point.
You mentioned a thin skin on the bottom of the adhesive!!
This does not mean it no longer needs sanding, for peace of mind I’d still want it done.
A 60# grit copper disc on a floor polisher type machine should work easily enough.

Sanded.
If you expand the image you can see the aggregates in the screed, that’s what we prefer to see before sticking even a mat to it.
When I say we, I mean the crew I personally work with.



Priming is an exact process too.
If it’s applied in coats that are too strong, it can form a skin instead of soaking in to thescreed.
Then you’re sticking to the skin and not the floor.
First coat should be very weak, 5/6-1 with water.
Second, slightly stronger.
If it’s still drying instantly, it could have another coat.
But it must soak in and not pool on the surface.

But your tiler should know this.

I would also insist on a 1mm antifracture mat on top of the screed too, before it was tiled.


As far as the product suggested above, Bal Flexbone 2easy.
Personally have no experience as yet with it, so I can’t comment on its suitability I’m afraid.

But it’s all assumption, very difficult to pin point all the reasons it’s failed without seeing it in the flesh.

 

[Benc]

Still no reason as to why the tiles have lifted! Waiting on a report from the rep of the screed product! The rep said that with having a liquid screed in the extension and normal sand cement screed in the house we will need an expansion joint to stop the tiles cracking! Our tiler has suggested using the anti fracture Matt but can this be used between the sand cement screed and the liquid screed?

 

[J Sid]

a mat will be good but will definitely need a expansion joint across ufh in new area. Would of expected there to have been an expansion joint put in by screed contractor between new and old.

 

[Dumbo]

Still no reason as to why the tiles have lifted! Waiting on a report from the rep of the screed product! The rep said that with having a liquid screed in the extension and normal sand cement screed in the house we will need an expansion joint to stop the tiles cracking! Our tiler has suggested using the anti fracture Matt but can this be used between the sand cement screed and the liquid screed?

Anti fracture mat if used would be over the whole area not just the join . But it is not a substitute for an expansion joint.

 

[J Sid]

I wouldn't put it over joint.

 

[Dumbo]

I wouldn't put it over joint.

Yes . Expansion joint should continue from the screed up through the tiles uninterupted

 

[Andy Rhodes]

In the extension on the UFH & cement screed, I would have laid anti-fracture mat to were it meets the original floor, dependent on how wide that room was I may have put an expansion joint through the middle of the room if it 3m2 or more , but defo left 10 mm round the walls just to give me piece of mind in case of any movement. as for between the original floor & the extension was I would have used some kind of movement joint either mastic or a trim type,but again from looking a the pictures you supplied I don't think in would have made any difference

 

[Benc]

Tiles are all lifted and the floor is being sanded this week! Going to use a acrylic primer! Can anyone tell me the proper procedure for laying this primer please?

 

[Benc]

 

[Benc]

Floor ready for sanding! Part of the floor is very uneven and a self leveling compound has to be used to bring it up to the correct level! Also laying an anti fracture Matt plus an expansion joint between the two floors

 

[Flintstone]

That floor looks to have suffered some cracking, it needs an antifracture mat.
If a screed is pumped - it needs sanding, simple as that, I've never seen one that doesn't need sanding.
The reason for the failures are-
PVA
Fixing method
Not sanded.
The tiler needs a reality check, don't let him fob you off !
I'd be calling the screed company too and demanding an answer and a resolution as to why there pumped in self leveling screed is not level !

 

[Benc]

He won’t be fobbing anyone off this time!!

 

[Flintstone]

Are you letting him have another attempt ?