Tiles Coming Off Screed Re-tiling Advice

[Joss]

Dear all,

I need a bit of advice, about 2 month ago I had the kitchen tiled (600*600 porcelain tiles) on 50mm screed. Last week I started noticing clicking around an area and I could see the grout was breaking. After lifting a tile with the tiler we noticed that 3 things happened:
- The scree seem to have dropped by half a mill leaving a gap under one adjacent tile.
- The tiles was completely loose from the screed on the screed side
- A thin layer of dust seem to appear between the tile and the screed which can be scrapped of (look at the picture yellowish zone, vs white zone which I cleared) which I can't tell if it is screed or adhesive.
Broken Link Removed

I guess the tiles were laid on a not dry enough screed. Please jump-in if you believe that assumption is wrong.

Now the questions:
- Is there a way to re-lay the tiles by just scrapping off the "dust" coat (since the tiles are laid perfectly flat it would avoid the extremely painful job of removing the well glued adhesive on the tile side)?
- If so shall I just do the clicking zone or the whole room?

I'd really appreciate your insight.

Thanks,
Joss

 

[Andy Allen]

What type of screed was it?
Was it a gyvlon screed?

 

[Joss]

Yes it was Gyvlon screed.

 

[Andy Allen]

Was it sanded and primed?
And how long was it between the screed being laid and the tiling?
Did you check it was fully dry?

 

[Joss]

It was brushed but not primed.
The grap was 22 days with first dehumidifier and then gentle heater (not underfloor)
No it was not tested for moisture (electronically).

 

[Andy Allen]

O'dear so many things wrong.
I suspect the whole floor will eventually fail I'm afraid.
TBH your tiler should of known all this...sand floor..prime...check drying times.. etc..

 

[J Sid]

Yes it was Gyvlon screed.

🙁

 

[J Sid]

what adhesive was used?

 

[J Sid]

didn't the screed company leave you an information pack?

 

[Joss]

I know I kind of got to that conclusion, sadly... I took a hammer and hit the tiles with the back of the hammer gently I can tell something's wrong.
It's fascinating though that chemical reactions "chemical reaction such as expansive ettringite formation between the sulfate in the screed and cement based adhesives" can be so strong on "stable" material (all the yellow orange part that you can see on the back of the tile is I guess due to that reaction).
Now do you think it'll be possible to salvage the tiles in some way or I just need to start from scratch again?