There will be a bit of ambiguity in my answers...because there's no true right or wrong way. But here I go anyway: 1. Is the decision to go with epoxy or non-epoxy grout based primarily on resistance to mold and/or staining or is one type better than the other as far as preventing water penetration? Epoxy grout will allow less water penetration than a cement-based grout. Being non-porous, it'll also be less liable to staining. I consider epoxy to be overkill in residential showers, unless you're into dying your hair in the shower, etc. One other thing, you have a kerdi shower. That will limit water penetration, so it's sort of one more reason that epoxy could be considered overkill. 2. If we don't go with an epoxy grout in the shower, would the Polyblend grout used on the floor be suitable or would you recommend something different? Polyblend or any other manufacturer's cement based grouts would be fine. I use product from several manufacturers. Some people are preferential to just one manufacturer. 3. I think I'm confusing "caulk" and "silicone"... Are they used in the same applications? If not, what is the difference? Think of silicon as a type of caulk. There are, in general, three types of caulk typically used in residential shower construction; latex, siliconized-latex, and silicon. Latex is easy to work with, but the least durable and the most prone to mold and mildew staining. Silicon is the most difficult to work with, but has the best water-repellent capabilities. Siliconized-latex is a hybrid, it's in between the other two. In a well-built shower, any of the three could work fine, though I usually use caulks with some silicone in them, either S-L or 100% silicon. Look for a caulk that is color and texture matched to your grout, that way the caulk will look like your grout. Some 100% silicon's are only offered in color-match, but not texture. Since you mentioned Polyblend, here's a link to Custom's Color Matched Caulk. 4. Is caulk and/or silicone necessary in a Kerdi shower? I have nightmares about mold forming on my caulk (or silicone?) and having to tear it all out. The only proper way to avoid caulk completely is to do a floated mud shower with reinforced corners. Other than that, properly pitched surfaces, proper ventilation, and 100% silicon caulk will give you the best chance. 5. If we do caulk/silicone, I've heard that it should be done at every change of plane. Would this include areas that would not be taking a direct hit with water or having standing water on them? Correct. In lightweight shower construction (tile backer board over wood framing, for example), adjacent surfaces can move independently of one another. Caulk will flex. Grout could crack. Now you have a Kerdi shower, that works in your favor, as water can only penetrate to the membrane. But in general, yes, for lightweight construction, caulk all changes in plane. 6. Specifically which product would you recommend? A caulk that is color and possibly texture (sanded or unsanded) matched to your grout. A caulk that has some silicon in it. So the brand of caulk could be related to the brand of grout used if your goal is to color match. 7. Although our tile is porcelain, we are using a travertine base molding that has many nooks and crannies that will need to be filled. I understand that they get filled in by grout. This base molding is lighter that our wall and floor tiles and the matching grout that we're using there. Can I use a lighter grout for just the base moldings? Yes, you can change grout colors within the wall itself. 8. Finally, would you recommend sealing everything once it is done? Or just sealing the travertine pieces? I'd just seal the travertine. Porcelain is already non-porous. Sealing grout can be an adventure within itself. Regardless, use a penetrating, vapor-permeable sealer.

If there is latent water behind the crack, I suppose a latex or maybe even a siliconized-latex could taking a while to set up. For silicon, the only time I've heard of it not setting was when it was an old tube, a bit past its prime. Even if the crack wasn't cleaned well, the silicon might lose it's grip, but it should still cure. Sorry I don't have better info for you, fortunately it's not something I've had to deal with. Mongo

Mom2reese: First of all - congrats on the new babykins... Second, way COOL faucet! Third - your question: Yes... you can remove the caulk - a razor blade and alot of patience will be needed. HOWEVER - unless you get WAY back and scrape out ALL of the coloured caulk - when you reapply the clear - the CLEAR will transfer a small amount of the colour through - kind of like a shadow of the shade... the only want to do it right - and this is going to be about as easy as getting your gumbs scraped - is to remove the sink from the stone - you'd have to "drop" the sink down from it's support system.... Then....... scrape off all of the coloured silicone and apply a new bead of clear silicone before you raise the sink back up into position and re-attach it to the supports (clips or sink setting cradle - ie - undercounter mounter - sink setter, etc) re-set the sink, and use the clear silicone to do the new seal - do NOT use the silicone ONLY to attach the sink to the underside of the stone....... ON THE OTHER HAND...... You COULD live with what's there now - to echo everyone else's opinion - and I concur... it looks really good as it is......... It's just how much does it bug YOU - as YOU'RE the one that's gotta LIVE WITH IT..... hth kevin

We have the same sink you're getting, black (anthracite) silgranit and we didn't didn't want to see the caulk or the chrome drain, so we bought a flat black drain and then used black caulk....you can see a photo of an example at the following link. http://stores.channeladvisor.com/bobsfaucets/items/item.aspx?itemid=1771866 We didn't purchase from this vendor but I wanted to quickly find a photo for you....It turned out great... Here's our sink...