On 2007-10-25 02:01:39 +0100, "
said:

I have a bathroom (not installed by me) which is lined with Travertine
tiles. Due to some plumbing problems, I've had to break a few around
the bath and they're now being replaced. Of course, this has uncovered
other problems - my tiles have not been sealed, and apparently with
porous rock this is a bad idea since it lets steam through to soften
the tile adhesive.

There are also other opinions:

http://www.marblecleaning.org/phpkb/question.php?ID=85

My tiler said he would seal all the tiles for an extra £50, which
doesn't seem like very much but it's a lot when you're already laying
out for everything else and it may not be necessary. Any thoughts?

Peter

Yes it is a good idea to seal the travertine because it is otherwise
difficult to impossible to remove marks and stains, splashes of
products used in the bath etc.

The tiles should have been sealed after installation and before gouting
and then again after grouting. If they weren't done before grouting,
then at least you could do that now.

This is a very easy DIY job but certainly doesn't need to cost £50.

The best product to use for the purpose is Lithofin MN Stainstop.
www.lithofin.de
You can obtain this from any good tile shop. It may seem expensive
at around £30 a litre but unless you have a palace, 0.5 or 1.0 litres
is probably enough for a bathroom.

It's important to follow the instructions and to use a suitable
brush/roller that doesn't leave foam and then to wipe off excess after
the suggested time, using more material if needed. The objective is
not to leave any sign of the sealer after drying.