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

 

[bugs183]

The best thing to do is explain exactly what you have, what each floor is, and what the height difference is between them etc, the more facts we have the better help everyone can give, otherwise we are guessing, pictures would be helpful.

 

[kaide]

I don't know whether it's a compound or concrete to level the floor. What is the difference? Our builder got his work man to level the floor and the next day, the tiler laid the floor tiles.
I really appreciate all your advice, so that my husband and I will know they should be doing tomorrow.

 

[kaide]

Hi Bugs183,
I have posted a picture of the kitchen floor but it won't show anything until they take the floor up.
Sorry I down loaded the picture twice. The concrete floor is nearly beyond the kitchen units on the left hand side. The plywood bit is the nearest in the photo. With the threshold, you can slide a screw driver underneath the tile.
As to height levels, we won't know until they take the floor up. Incidentally, the original floor had small ceramic tiles and they didn't move or creak.

 

[Martyn Leeds]

The builders are coming back tomorrow?
What does the builder say is causing the movement?
Obviously he thinks that changing the plywood is going to solve whatever the problem is,
but as you've seen already, there's a few other things to consider.

I think you should do a bit of detective work tomorrow, take some pics of the removed tiles and get a few on here.

Once the floor is removed, then describe the situation and assess best preperation methods on here, and with the info you've already got you can tell the builder to hang fire with the tiling untl its all prepped correctly..

Also, Usually you'd have to beg and argue for the builder to fix things - but by the sound of it he's happy to re-do it, maybe he know's something that we don't?

 

[bugs183]

As you say hard to tell, until it comes up, shame it looks nice and flat looking at the reflections
You'll have to dig a tile up and find out if it's dot n dab, if it is, no matter what the tiler says it's been fixed incorrectly.
Also i take the underfloor heating electric, if so did the tiler lay this out then level over this with leveling compound, if he tried to tile directly over the mat (dot n dab or with a trowel) it is prone to failure and also there can be hot spots in the matting where no adhesive has covered the mat.

 

[kaide]

Hi Martyn Leeds,

Thanks for your advice. We will definitely take photos tomorrow and post them.
We were surprised that our builder responded very quickly. Our builder works for the company director who owns the building company. Hope that makes sense.

 

[cam_low]

Tomorrow no works need to take place apart from questioning the builder as to what his methods of fixing the failure are and lifting one or two tiles to show tge fixing method.
Clearly you now know there are a few factors towards the failure.

I think this issue may go on a little longer than you anticipate. Hopefully the builder will comply on all levels and keep you a happy customer!

 

[kaide]

Hi Bugs183,
Thanks for your reply. The builder's work man did the self leveling. We think the self leveling is concrete. It's grey in colour. The tiler then tiled over the floor the next day. When the tiler re-placed a cracked tile, you could see the orange electric heating mat. How deep does the mat need to be? We understand that the heating mat will be damaged when the tiles are taken up. We will be definitely taking photos tomorrow when they take the floor up.

 

[Stef]

They must put the heat mat into a self level screed & it's sounds as though they haven't.
I bet when this is ripped up all tiles, or most of them, are dot dabbed onto the floor to get over the heat mat.

 

[bugs183]

Sounds that way doesn't it Robson, people look at me like i'm mad when i insist the underfloor heating has to be leveled over, 'sorry for doing your job properly!!'
I bet the builders man didn't prime the floor, so i bet all the self leveling he used is shot as well, it will be after the floor is removed.
Not sure what your asking, but you need to have a nice flat flat floor (hence the leveling already done), then you lay the mat out as needed, then you self level over the top of this, to cover and protect the cable, usually 4-6mm depending on the thickness of the wire. This is left overnight, then the tiler can tiler over the floor using a notched trowel 8-10mm to trowel the adhesive onto the floor, then each tile is back skimmed (adhesive spread out with a flat trowel across the tile back), then laid into the already notched adhesive, if the tiler needs to adjust a tile he adds or removes the adhesive needed, but NEVER spots adhesive, if he's prepared the floor correctly he should never need to dot n dab.