travertine sealer for bathroom

[sparkybaz]

ive just had my bathroom done in travertine and the tiler has made an absolute balls of it to say the least.he used ltp ironwax to seal the tiles but when ive read the bottle it says it should not be used in wet areas's,is this right !.
also is there and form of waterproofer that can be used in the shower area or is the ltp ironwax good enough.
all advise appreciated

 

[sparkybaz]

the walls are dot and dab plasterboards,i removed the old tiles but due to the surface being too rough i first applied a gypsum bonding base coat"glue particles"then applied a finish coat over that to give added strength,rather than just a finish coat over the old rough boards.the tiler then used a sealer to seal the bare plaster to stop the adhesive drying out too fast.
as i say it looks ok and all feels solid it was just the aspect of making sure the tiles are 100% waterproof and nothing is going to penetrate the tiles or grout and attack the wall causing future problems