Cracked travertine over Wet UFH - help - TilersForums.com

[Jason20]

I would be grateful for any advice you could give me. I have recently installed 600x450 travertine tiles in a fairly large conservatory 6.5m x 4.5m over wet UFH. Used 8-10mm beds of flexible adhesive and flexible grout with 3mm spacers.

My father did the installation. He's a bricklayer so is very handy and had done a very good job. However....he has not used a membrane over the screed and has not installed an expansion joint. I have a manhole in the centre of the room. Naturally this is avoided by the UFH so remains cold. It's been tiled over. When I switched in the UFH a crack developed from the back of the house to the bi fold doors, through the middle of the cold spot.

i can take up the damaged tiles but I want to limit the chance of this occurring again when the tiles are relaid. I'm guessing my best bet would be an expansion joint -would 5mm of silicon along the fault line do the job? Any suggestions would be sincerely appreciated.

 

[Gazzer]

Did you commision the UFH before tiling? What type of screed is it ? How long after laying the screed did you tile ?
You say you switched UFH on, did you turn it up slowly ?

 

[Ajax123]

When you say 8-10mm beds of adhesive are you talking blobs of adhesive into which the tiles were pressed.

Natural stone, and particularly travertine, are relatively soft and fragile along the natural fault lines and as such require an uncoupling membrane over heated screeds.

It sounds like a few mistakes have been made and it will be Lmost impossible to guarantee that replacing the tiles won't lead to the same happening again. You might even be better off repairing the crack and living with it.

 

[cam_low]

Good posting as usual Alan. I always use an uncoupling mat worth natural stone.

 

[Jason20]

The floor's been down for 3 years so it's well established. Previously carpeted but that held in too much heat. Not sure what type of screen but it was pre mixed, laid by hand and is probably 75 to 100 mm in depth. It does have a fibre content. The heating was left off for a few days for the adhesive and grouting to set but was turned back on as normal not gradually.

No dot and dab. Adhesive was laid on the screed using a notched trowel and the back of the travertine was buttered.

yes with hindsight (or decent foresight!) matting should have been used but too late for that now so my question is will the creation of an expansion joint help?

I will try to live with the crack for a few weeks. It's not tha bad, but it's there! I would like to know what I should have done and what I can now do to mitigate the problem.

Thanks for your responses guys.

 

[Ajax123]

You should have uncoupled. It is unlikely that you can mitigate now as you would have to lift the tiles nd uncouple them. The bay is not big enough for an expansion joint but the fact you have a manhole men's you should hVe had a joint around it which reflected through the tiles. That would probably have looked horrid.