This sounds remarkably like our current situation (I believe it actually could be our sceanrio)...
We purchased black Quartz tiles (composition of 93% quartz and 7%polyster resin binder) from a supplier and had them fitted by a well regarded and recommended tiler in the area. He fitted them onto Under Floor Heating, however prior to completion it was recommended that we didn't actually have the UFH connected/wired in as apparently this has in the past caused problems with this tile type so we reluctantly agreed to have wall mounted heaters installed at a later date)
Approx 6 weeks past and then we noticed that 5 of the tiles had risen so we subsequently called the tiler and he re-visited and carried out the replacement of two (both bowed considerably). These tiles do actually have sun exposure via French doors in the kitchen and when the sun is out for a period of between 8-1pm. The tiles do become warm I can concur.
We have now experienced the same at the other end of the kitchen, however these 7 tiles are not exposed to any sun at all. We have the usual kitchen appliances (cooker, WM, DW) however all were brand new and insulated after consulting with the suppliers. I have taken the temp around them and it raises by a maximum of 3 degrees so my opinion would be that heat is not the issue here, however am open to ideas.
The method the tiler used was:-
- Tiling was done using 10 mm notched trowel
- Tiles were skimmed back with more adhesive to solid back over underfloor heating cables
- underfloor heating is not connected and was never turned on
- The sunlight beams through patio doors and proportion of the area gets warm between 8am-1pm & on sunny days the area gets rather warm.
- Two out of five raised tiles warped (like banana shape) where the sun has hit
- The tiles also pop up where there is no sun exposure (this is an area more affected)
- Cooker might give heat from the bottom, however is insulated (manufacturer says) by 3 degrees (the tiles located closest to cooker have not raised)
- 20mm expansion gap were left all around the room
- The adhesive used is Palace Chemicals part flexible adhesive grey
- The grout used is Bal flexible wide joint (5mm grout over the entire area)
Really look forward to your professional opinions here, however the tiler has arranged for Palace Chemicals to send a representative now for their opinion. Sorry for hijacking the thread if this isn't our scenario (we just want a flat floor).
