"Tom" wrote in message
om...
Hi, I recently noticed that in some spots my travertine floor
(exterior and interior) has a white flakey build up in certain spots.
If I broom it off, it comes back after a few days. Someone told me
that this is a natural occurence of oxidation in the natural stone. Is
there anything I can do about it and is it a problem? Thanks.

I don't believe it is natural oxidation.
You might check for moisture under the tiles that show this buildup,
especially if the rock is installed over a slab base. Travertine is an
extremely porous and sometimes permeable limestone rock that when in contact
with a moisture source will wick up the moisture along with dissolved
sulphate or carbonate salts from the rock itself or from the mortar
underneath. Efflorescence - look this up! - occurs when these wicked
solutions hit the air at the surface of the floor, and the evaporation
causes oversaturation, and the salts precipitate out . One test for
moisture might be to put a piece of newspaper on the freshly cleaned tile,
then cover the paper with a weighted piece of glass, then check the paper
after a week or so. If wet, then you have a seepage problem.