Tiling natural stone onto concrete slabs

[Gordon@stone-cellar (UK)]

Hi All,

Got a customer who wants to tile 10 or 12 mil commercial travertine tiles onto concrete slabs to use as an exterior patio. This is to keep cost down and rather than use a thicker travertine slab outside. I have advised that I don't see it as a good idea.

Can I have any thoughts from the experts on if they have ever done it and if not why not?

Thanks