[quote=
tiler-101;34879]Sounds like a 4.8x4.8 unfilled travertine either noce or chiaro.
Get the ply screwed or nailed at 150mm centres, mark it up then prime with a suitable primer I'm sure there will be screams of Bal but its your choice and a pva will do it. To lay them I would use a rapidflex adhesive with a 6mm trowel making sure you remove an adhesive of the surface with a damp sponge.
When you are comfortable that they are dry then you can grout them. A mapei grout is ideal for this as its very fine and can be pressed info all the small holes (its also flexible and can be used to over 10mm grout gaps) . Its important you use a grout that is fine, most floor grouts are too course for travs and it doesnt get into all the pores. If u dont fill the pores they will turn black with dirt and washing, this applies to filled and honed travertine also, trav is a sedimentary stone and riddled with holes. Grout as u would normally with a little more care, often air gets trapped in the pores and so dont fill with grout.
When you have grouted go over the floor with a damp sponge or a sponge pad, grouted mosaic always finishes better with the pad. Now the excess is gone leave untill the surface of the mosaic looks dry and wipe again, mapei grout goes off in about 20mins so is good for this job. If after the second wipe there is some grout stuck take it off with a stanley blade. Wipe up clean when ur satisfied the floor is dry.
To seal it it needs to be dry and so should be left until then, give it a couple of coat of a good sealer and buff up when dry
This should do it for you
101[/quote]NOT PVA...With respect I followed the PVA brigade for years making good de- bonded stuff....Gaz