Expansion Joints

[Mr Blobby]

GF tiles have arrived and we are a week away from the tilers coming on site. 

Tiler says there is no need for expansion joints, he just leaves a gap and fills with silicone and then they are almost invisible.  I'm naturally concerned.  And I suspect that the only reason to run a bead of silicon is to save money on the expansion strip.

 

Tiles are 120x60 on KORE slab.  And its a big area, about 120 m2 total.  Unlike screed there are no expansion breaks at door thresholds where I think the expansion strips would probably go.

UFH in slab but uniform low stable temps.

 

Do I need expansion gaps and if so then should I insist on proper aluminium (or stainless steel?) expansion joints instead of a line of silicone?

 

 

What are the best ones to get? The schluter are twice the price of genesis.  And how wide, 8mm?

 

And should the floor be primed first?  I think a uncoupling mat is probably unnecessary?

 

[Mr Punter]

If there is crack control breaks in the slab you will need to follow these in the tiles.  If not, you should be OK with nothing.