Crack in the screed with travertine.

[timburr]

Hi. I'm short on experience here so if I can have the advice before I screw it up that would be great:
Its a kitchen floor 'L' shaped currently 30 m2 but growing to 50 m2 next phase. The screed has embedded ufh pipes as yet pressurised but not commisioned. Its been airdrying for 5 months, is 80mm thick dry mixed with fibres, on celotex. A fine crack has appeared between the arms of the 'L'.
I was proposing to use travertine directly onto the screed in a roman opus pattern, but am thinking now that expansion joints I might have to provide will be difficult in this pattern?? I guess a silicon joint over the crack would be good but I dont see how to achieve it. Phase 2 joins a separate floor to phase 1 to make a tiling run 11m long, and will have a joint in the screed where the wall was removed. I've figured from reading various threads I must at least heat and cool the screed before I start laying, what else have I missed. I haven't bought the travertine yet. I'm a builder with experience tiling bathrooms mostly but this is my first big stone job.

[timeless john]

I'd always recommend an uncoupling membrane and an expansion joint will be required within your 11mt length, almost certainly at the join in the screed.
50mt is a good size area and for a first big stone job, I'd suggest you gather some input from a local experienced tiler and certainly further step by step information from the Best Tilers Forum around.

[jay]

some pics might help

[Diamond Pool Finishers]

good advice from john above, uncouple every time,and you will deffo need provision for expansion!!