porcelain floor tile movement

[kaide]

Hello,
Looking for some advice. Had our new kitchen fitted last October. The floor is half concrete and half wooden. The builders replaced the floor boards with 18 mm plywood and leveled the whole kitchen floor with self leveling compound. We also had electric under floor heating put in as there is no radiator in the kitchen.
The porcelain floor tiles move over the plywood area. Also, when you tap the tiles, a fair few of them sound hollow over the concrete area of the kitchen. The builders are coming back tomorrow to rip the floor up and replace the plywood with 22 mm and do the floor all over again.
Can any one shed any light as to why the tiles sound hollow on the concrete sectioned and movement on the plywood section please. The tile adhesive they used was called setaflex and is the correct adhesive.
The under floor heating was put on 3 weeks later after the floor had been laid. The builders gave me no instructions as how you are supposed to gradually increase the temperature. I had initiallty had the temp on high for the first 24 hours until they told me otherwise.
Any advice much appreciated.

 

[cam_low]

When you say they move do you mean they wobble?

The hollow sounds could point to the old and very infamous builders dotndab technique. Which is completely the wrong way to fix a tile.

with you turning the heating onto full may have thermally shocked the tiles however I'm guessing that they have not implemented any expansion joints from one substrate to the next. I'm currently in the bath (best place to catch up on here!!) so will reply fully when I'm out however someone will more than likely beat me to it !!

 

[DHTiling]

As above was there an expansion joint put where the 2 substrates meet and how did you/builder commission the under tile heating.. ?

 

[Andrew]

Get it ripped up, replacing the 18mm for 22mm will not rectify the problem! Once it's ripped up insist it is re tiled by a professional tiler and not a builder who thinks he is one! I am kept in work by re doing builders incompetent tiling, but equally frustrated that builders get away with such shoddy work!

 

[Perfect Tiling]

As the other guys say. I know you probably don't want an expansion gap across your floor but you can't tile over 2 different sub floors as they react differently. The hollow sounds are definately a sign of loose tiles which could be related to them being laid wrong or due to thermal shock from the heating being turned on too fast and too high. How long has the concrete been down...it could still be green (wet) which will stop the adhesive getting a full bond. Replacing the 18mm ply with 22mm ply really isn't going to solve the problem. What I would be asking is if they are builders.......are they really tilers. Lots of builders, plumbers, joiners etc say they do tiling.....but if you want it done right you really need to get a tiler to look at it...hence tilersforum!!

 

[Perfect Tiling]

Oops...I must have been typing as Andrew put his reply in. As you can see...two of us "tilers" are saying more or less the same. Its up to you.

 

[kaide]

Thanks ever so much in replying to my post.
The floor tile movement is a slight up and down when you walk on them. This has meant that the grout between each tile has cracked and crumbled.
As far as expansion joints, I don't know. Incidentally, what are expansion joints and what do they look like.
The tiler did replace a cracked tile before Christmas. The old tile looked like 4 blobs in each corner of the tile. I hope he hasn't used a dotndab technique.
Thanks

 

[White Room]

4 blobs in each corner, dos'nt sound clever:yikes:

 

[kaide]

Our builder has employed a professional tiler and it's the same one that is going to re-tile the floor. The tiler laid the floor tiles down less than 24 hours after the self leveling concrete. Our builder has even suggested getting a structure engineer to check the joists.

 

[DHTiling]

It now seems to be a de-bond due to lack of adhesion... this along with stress from UFH and 2 different substrates t hat expand at different rates...

Your tiler and i use this term loosely, needs to be called back and tell him he has need fixed the tiles in accordance with BS5385 .. and watch his face.

 

[cam_low]

Take a Stanley knife or a grout rake (bnq,topps tiles) to the grout and post some pictures up of the back of the tile.

 

[bugs183]

Sounds like classic dot and dab if you can see blobs. If your tiles sound hollow it could also be that the leveling compound is loose, you said the builders did it, and they never do it right i always tell any customer to let me do the leveling not the builder.
To be honest this job isn't sounding too promising.
I wouldn't use ply wood again either i'd be tempted to overlay the concrete and wooden floor in cement board such as Marmox. This is much more stable than plywood, is a much better surface to tile too and it's insulated so the underfloor heating will perform much better.

 

[bugs183]

When you say self leveling concrete do you mean leveling compound or have you had a self leveling concrete floor poured and then the tiler went straight onto it????
These are two very different things.

 

[kaide]

Thanks Dave,

My husband is now googling BS5385. As we have two different substrate levels, does that mean we cannot have a porcelain floor and keep on having problems?

 

[Mr T]

I think and expantion strip would more or less look like a door strip running straight along where the 2 substrates meet