Cracked tiles?

[sean@silverfern]

Hello everyone.

I have an issue with a bathroom floor I have laid.

Bathroom floor was rotten and replaced by the joiner, who was also acting as ‘sort of ‘clerk of works on this residential refit. He said the floor was solid and all fixed. I could see it was overlaid with 18mm ply, so believed him and went ahead.
I laid the tiles back in June. A few days after they were laid the grout around a few near the door started to crack. The joiner inspected, said they were loose and needed to be replaced. I thought I'd made the grout mix too wet but anyway agreed and replaced the tiles that he indicated as loose. About 4 altogether. None of them appeared loose, one did have a small cavity but I cracked several removing them as they were hard down. But the job was done anyway.

Now seveal of the tiles, including some of the ones I replaced, are cracked. Customer called me back to the site and I saw that the crack was in a straight line thought 4 or 5 tiles. Tiles near the door appeared loose too with grout cracking around them. I lifted these tiles and discovered that there was a crack in the adhesive running in line with a joint in the plywood. See photos 2 and 3.

I believe that there is movement on the floor or stress in the floor somewhere, propogating at the join of the 2 ply sheet. I have looked closer, as in photo 4, and I think the 18mm ply is directly on the floor joists.

I believe that if I lay further tiles down again they will soon crack and that the problem is with the floor. There is no sight or feel of movememt in the floor.
What do you all think? And what do you think is the best course of action?

Single part flexible adhesive was used. Ardex X7R first, then when I replaced the tiles, weber rapid-set. Just because I had run out of the Ardex. The tiles I replaced I ensured were well stuck down, as you might imagine. There are no other problems with the floor elsewhere, including under the bath. All other tiles are solid.

 

[J Sid]

The ply is moving due to movement in floor or moisture getting into it. Was the back and sides of the ply primed as per instructions on the adhesive bag before chippy put them down? Still can't believe people tile straight into ply when for a small cost in a room that size a uncoupling membrane could have been used and this would not happen. See it so many times and so often the so tiler just walks away. Good on you for trying to sort it out. This will be a rip up and start again. IMO.

 

[pete f]

yep as julian says take it up and redo ittimber floors need overboarding with 6mm hardiebacker boards glued and screwed 150mm centres

 

[Protilers]

I think it is likely that there are no "noggins" in the floor and therefore the joists are flexing individually. If it was me I would lift the lot, insert noggins @400 centres, install 18mm wbp and cover in schulter ditra....and tile it again!!!

Best of luck

Lee

 

[Martyn Leeds]

Agree with all above, and I don't see the point in tiling direct to ply when there are numerous products out there..

I'd want to know a bit more about this 'Joiner' bloke and what exactly is under this floor, as by the sound of it, only he knows??

 

[cam_low]

where does the blame lie ?

 

[J Sid]

Hi cam, the blame must lie with the tiler. He should have checked the surface was good enough to take the tiles.

 

[Protilers]

in the U.S tiling is just a "laminate" and therefore the blame would lie with the "joiner".....in the E.U if we (as Tilers) accept the surface as suitable to tile on and tile it.....the blame lies with us!
seems a little bit odd as we cant see "under the floor!".......under that lovely 25mm Fermacell board is only a couple of joists and they are 4x2's!!!!!.....scary!

 

[sean@silverfern]

Thanks for your replies everyone. Will wait and see what the joiner has to say about things. He's already said if it's the floor he will hold his hands up to it. He is a qualified joiner with more than 20 years experience and seems a good bloke. I have been tiling for 7 months.
Thanks again.
Sean.

 

[Bathfix Bob]

Hi Sean.......I'm sure his floor was solid enough but really as a pro tiler you should have treat it as a base and gone further a field with the prep. Three years ago I had exactly the same thing happen to me straight over the ply joins, in that case I removed the offending 4 tiles and fired extra screws along the joins and replaced the tiles. They never rang again and they are a friend of a friend so I would have heard if they failed.

Learn from this as I did....don't tile on any more wood as it will expand and contract and curl up and lead to exactly this, always lay cement board (Hardiebacker) on 6mm bed of tile adhesive and screw down, you will not have any more problems if you do this.

 

[steve187]

never trust anyone else's prep, why the small cut under the rad.

 

[sean@silverfern]

never trust anyone else's prep, why the small cut under the rad.

Yes, I have now learnt that lesson.
Small cuts due to customer wanting the mosaic strip at a certain height. I have learnt a lesson from that too.