Floor tile grout space/width with UFH?

[Orlando5007]

Hi all hope your well! 

I have to tile roughly 28sqm over a screeded floor which has water underfloor heating. The tiles are porcelain laminate wood effect tiles so thin and quite long. I want to keep the gaps to a minimum but have been told 3mm is the lowest I can go, is this correct? 

[Temp]

I've heard the same. Apparently the grout can crack and come out if the gap is too small.

[Mr Punter]

Yes and according to my tilers the tiles need to be really flat.  Try pairing them back-to-back and front-to-front to test this.  If they are a bit out they will be better if you reduce to, say 1/4 bond stagger. I have heard good reports of tile levelling systems which you may want to look at.

 

 

[nod]

You can drop down to 2 mil 

4 is better 

The Turkish and Chinese slats tend to have a camber So using a levelling system won’t help

If you pay a bit more for laser cut Italian or even Spanish you will find these to be very flat 

Regardless of what you use you will need to back butter each tile with the smooth edge of your float