Trebor thought you were a tiler m8 sorry on that score. If your sealer is a water based one then you could seal them before grouting fella if not you best wait untill they are dry, on average 3 days.
If the travertine is honed then go steady and grout it whiping the residue off the tiles when it turns cloudy. The trick is to rinse your sponge after each pass and keep it as dry as possible. When you are done walk away then go back an hour later and whipe it again.
Then you need to let it dry out before buffing it off with a dry cloth, hoovering then sealing.
So you see what I meant stone carries a premium of up to £15 a m2 extra to lay, in a lot of cases its difficult to see exactly what some tilers provide for the extra money which is taking the pi**
Be lucky if you need more just ask
tiler
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