Hi All I am just about to start laying Travertine Modular Mosaic(Turkish) natural stone in my bathroom.I have started preperation by repacing all new Joist and all new floor boards, solid as a rock.

Q1 What ply 9mm or 12mm?
Q2 Do I PVA the ply or what would you recomend?
Q3 Do I seal the tiles before laying or after?
Q4 What adhesive should I use? Please state if ready mixed or not.
Q5 How long should I wait before grouting?
Q6 What grout should I use? Please state if ready mixed or not.

Thanks in Advance

Cheers Kenny And a Verry Merry Christmas to you all

Hi Kenny.
I presume it is just the floor you are tiling?
Anyways in answer to your questions
1) id use 12mm exterior grade ply, screwed down at 20mm centres. (secrws to be shorter than the total thickness of the ply and floorboards-saves screwing into pipes or wires). Other chaps might recommend thinner cement boards, saves lifting the floor so much.
2) No pva, ever. Prime with a suitable primer, consult you tile stockists not a DIY chain.
3) Depending on the area, if it was small i would seal the tiles before laying, then pre grouting and finally post grouting as well. A good impregnator rather than sealer would be my choice as well, again consult your tile stockist. IF it is a large area, say more than 5 to 10 m2 the it would mean setting out too many tiles to seal before laying and just make sure you work clean and do not stain tiles with adhesive.
4)Do not use ready mixed, use flexible powdered gear, possibly 2 part for extra flexi. Bal do a really good one. Some guys might recommend a decoupling membrane like ditra matting because of the fragile nature of trev. I must say i havnt used it and had no problems.
5) The bag of adhesive will state how long to wait, if you use the most common floor addy, it will be rapid set, ie groutable in a few hours. Id aim to tile one day and grout the next if you havnt done it before. Sealing inbetween.
6) Ready mixed grout is only sold by DIY chains, if your buying gear there then forget it. Use a flexible powdered grout for floors, ususlly wide joint as supplied by a known tile supplier.

A few other things to think about. Are the tiles calibrated, ie are they all the sme thickness and size. If not the open up the grout lines to compensate. If they are the 3-5 mm would be fine.
Are the tiles filled/honed ie are there holes in them or are they pre filled? IS there a glaze on them. If they arnt filled then the holes will be filled with grout when grouting and shouldnt be sealed before hand.

Good luck.

Originally Posted by davy_G

1) id use 12mm exterior grade ply, screwed down at 20mm centres.

I'd read that as 200mm centres Kenny.