I'm bumping this message since I am having a similar issue with my Travertine & grout. I thought I'd seen messages in the past outlining best practices, but am not searching correctly or in too big a rush. My primary problem is I probably have not sealed often enough -- will change my habits once I can correct this problem!! -- then DH decided NOT to suck the cool, air- conditioned air out this summer so he began turning off the vent as he walked out of bath. We have a very nice in-line vent installed in the attic space above our vaulted ceiling Master Bath with a timer on the vent!! (Not sure where he got the idea he was saving electricity?! We live in GA so its pretty humid & he grew up in Louisiana . . .) So now I'm attempting to get back before sealing again. I have a issues with a few "pores" that have mildew where a razor sat, so also want to clean that out. There is mildew on some grout which seems more stubborn (or is stained). My primary cleaner that works well is TileLab "Everyday Cleaner". It does a great job with the orange gunk & soap scum (even for water spots on the glass door & walls). I use a soft vegetable brush on difficult places & soft toothbrush on "sanded" grout. I have read that Hydrogen Peroxide or Tea Tree Oil will kill spores & clorine bleach will bleach the color. I know I shouldn't use clorine on my Travertine, but am interested if I used the Clorox Bleach pen on the grout & washed soon & completely if I'd be safe or if Peroxide or tea tree oil will hurt the travertine. Some threads suggest an Oxy-Clean solution, as well there are Non-clorine bleach pens that might be helpful. I want to be expedient & correct my problem before it gets worse. Thanks for any advice you can give me.

I've never heard of this product, and I'd like to see an MSDS (on the grout cleaner) before I pass judgement on it. However, one thing I did see was the following: Since the Sealer actually bonds to the grout, it is able repel water, food, grease, mold, mildew and more keeping grout looking new! It is colorless and protects the natural color of grout against stains, Ultimate Grout Sealer contains no harmful solvents. Two things wrong with that quote. First, sealer shouldn't repel water. Any sealer that repels water from getting in, will also SEAL moisture from getting out, giving mold and bacteria a chance to get started. This is the whole reason why the best sealers on the market are breatheable. Secondly, it touts the fact that it's not solvent based. This is kind of a kick, because solvent based sealers are known to be much better than water based. They penetrate deeper into the stone, and therefore, last much longer than water based sealers. It would seem to me that this product is targeted toward DIYers and end useds, because no one who knows what they're doing would use such a sealer.

I built a surround, mantel and overmantel using MDF, various moldings and honed travertine tiles (filled). I don't know how to post pictures, but, if you e-mail me I'd be glad to send you some. To answer your questions: You can install the travertine directly on the drywall using fortified thinset (don't buy the pre-mixed kind). Just make sure the drywall is well anchored, I drove some extra drywall screws into the studs before installing the travertine. I didn't seal my tiles, but, the honed finish is smoother than what you have. The reason to seal before grouting is that the sealant acts as a grout release and makes it easier to clean the grout from the tiles. With rough tiles I've found it helps to keep a water spray bottle handy which you can use to flush out any grout that gets in the holes before it sets. 1/8" spacing is good, however, if your tiles have rough edges you may have to go to 3/16". On the hearth you need plywood for strength and then you should put down some wonderboard or hardiboard. This is because code usually requires at least 1" of non-combustible material on the hearth (check your local code to be sure what the requirement is). You meet the requirement by calculating the thickness of your tile plus the thickness of the thinset (1/8' - 1/4") plus the thickness of the cement board. You should err on the high side. Hearths can get pretty hot, so the thicker the non-combustible layer the better (it acts like an insulator). Also remember to check your local code on the required clearances from the firebox opnening to the mantel and surround. In most jurisdictions this is 12" (for non-combustible materials). I used some corbels that are closer but I bought some made out of molded stone that are non-combustible.

We had a similar situation with our house. I ended up having a professional stone restoration company come out and clean the tile and grout and then seal the floors. They first used a cleaning solution followed by an oxalic acid solution and a 200-400 grit honing powder prior to sealing and buffing. I must say our floors and grout came out beautiful and were well worth the money spent. It was extremely important to me that our floor and grout were as clean as possible prior to their first time being sealed.