Popping tiles

[Caly]

Just lifted an existing floor of 30 x 30 tiles laid onto 4mmm (?) ply with what appeared to be a non flexible adhesive and grout, it had been down 10 years with just one cracked tile.Lifted the ply also.

Now; modern methods.........laid 9mm ply screwed every 150 square (onto floorboards), primed, laid 60 x 60 ceramic using one part bal flexible and grout with flexible grout (bal again).

1st problem..noticed grout had actually shrunk back and cracked in quite a few places.

2nd, Some tiles have started to "pop", that is move up & down, you cant pull them out of their bed using suckers, but they will move.
I can actually put hand pressure on tiles and they will show movement, especially on corners.

Left the job over xmas and will obviously go and re grout, but concerned about long term effects.


Anyone with any advice, remedy ?

Caly

[kilty55]

h caly

despite the fact that the last installation was laid onto 4mm ply and it lasted doesnt mean these methods will be okay next time round i would call the customer lucky on that occasion

9mmply still isnt sufficient either it needs to be minimum 15mm

you said you laid 600s, did you back butter these or solid bed to ensure good coverage,my initial thought is that you havent acheived full coverage and they are lifting due to this possibly

i wouldnt back butter 300s but i would with larger formats like the 600s

what state was the floor in was there hollows etc and did you pack out or do the above?

[kilty55]

only remedy imo is rip the lot up imafraid if the tiles are moving your not going to save them by r grouting

[Sir Ramic]

15mm ply is min BS spec.
It should also be WBP ply. The trouble is these days is the quality of any ply available. Ply is ok to add strength ...but I dont and wont tile on it anymore withouth cement tile backer boards.

[Bri]

the ply is the problem here, 15mm is the minimum thickness that should have been used. Has the adhesive de-bonded fom the tiles or the ply?

[tfs]

As the guys above have said.

Also, you will probably find that it only the grout thats holding them in place at the minute. If you do proceed to lift them you will see exactly what we mean.

Sorry to hear the trouble your having.

[TF Ed]

i personally think if you have no chioce but to tile on ply, then the face of the ply needs to be suitably primed first. some adhesive companies claim you shouldnt prime the face, only the rear and side but imo, you provide a much more suitable surface if its primed and the suction is controlled much more effectively...

i dont like tiling directly to ply because it goes against everything ive learned since 1985. its too unpredictable/unstable and imo cement based products, even with polymer additives, do not adhere well to wood.

[Caly]

Many thanks for the replies. I have projected managed this job and draughted in "reliable" tilers (?)

I like to seek good advice and obviously did not find it with their advice of 6mm will be fine (ply) so being one that always takes responsibility, looks like its coming up.
Just when I closed at Xmas with a positive in the bank, now look where its going to go.

[kilty55]

oh dear,stick around caly you will find plenty good info on here for your next installtion

[tfs]

Hang around here caly and you wont need to ask any of those guys a question ever again