underfloor heating...cracked tiles

[billozz]

hey guys,
major problem, i have put under floor heating in my bathroom ( the wire type ) and have then tiled over it, before i tiled i put some 12mm plywood over the old boards as they werent very good and used the flexible adhesive to fix them, no probs to begin with heated up great, but after about a week or so i was in the bathroom and heard a loud bang, i couldnt work out where it had come from as there were no visible signs of a crack, but when i looked more closely i could see a very faint line across a couple of the tiles they looked as if they had cracked but the surface of the tile (the porcelain) was not cracked, i am not sure why this has happened as we were assured that the tiles were suitable for underfloor heating, obviously i am concerned as to why it happened but, more importantly i am looking for a way to put it right, i dont think it is going to be easy to lift the tiles due to the wire which is under them, though the experts amongst you may be able to suggest something, i hope so the thought of having to scrap all the tiles and the heating wire doesnt bear thinking about hope you can help
thanks
Bill

 

[jefoss]

might be an idea to get the underfloor manufacturers along, it will cost you initially, but they will give you the exact problem and where to look for sorting it, i.e. if underfloor heating is **** or if the tile company told you lies. (im guessing the latter)

 

[joe-90]

Sounds like the flexible adhesive wasn't flexible. Did you keep the packet or remember the name?

 

[Jasonb]

How long until you turned the heating on, the adhesive needs 28days to fully cure. Did you use a flexible grout as well, how were the boards fixed down? Did you use a solid bed trowel so there are minimul voids under the tiles. Did you tile straight onto the lire or set it in self leveler first, not all SL's are suitable for UFH.

A few more details will help.

Jason