Old caulk can cause problems. I've never seen caulk "crack" though. I have seen, when it is put on too thick, too much at once, or when it's put on an unclean surface, or put on a surface that was previously caulked with 100% silicon... In those instances I've seen it pull away from one side of tile. Normally due to shrinkage as it cures. But I've never seen the bead itself crack. For deep gaps you can use foam backer rod to "fill" part of the depth of a deep gap. Then you can caulk over the backer rod. New construction it could be house movement, caused by wood shrinkage. The baseboard is shrinking in the dry, less humid winter months, and "pulling up" away from the floor. If the caulk failed due to shrinkage, then you can sometimes go over it with new caulk and blend the two applications together. But it's hard to diagnose if it's excessive house movement or bad caulk. Since you've caulked before it's probably not operator error. If the caulk was bought recently at a store with good product turnover then the caulk was probably fine. So it could just be the first-year construction settling in during a dry winter.

I'm extremely disappointed in Fireclay. Why aren't they forthcoming about appropriate uses for their tile? It's not cheap, I'm willing to pay whatever...but why are they the only manufacturer that says crazing is ok in wet environments? If they had a proprietary improvement in their tile, I'm sure they would share it! I don't think they do. I had a custom tilemaker tell me that their tile is perfectly fine to go into the wet environments...followed 30 minutes later in conversation by saying there likely will be some soap scum in there and to be very careful because the grout will go into the crazing (so don't use contrasting grout). So, to me, that is NOT perfectly fine! Tile - especially at Fireclay's prices - should not have ANY of these issues - and because they will, Fireclay should be forthcoming about the technical specifications and appropriate uses. They even say their tile can go in swimming pools!!! That leads me to believe it's sealed - but then there are these issues with the grout seeping into the crazing, even after sealing upon install, so clearly it's not. Bar Keeper's Friend?! After paying a RIDICULOUS amount for their tiles and WAITING for it to be custom made...not being told the proper technical information, then being told use Bar Keeper's Friend?!!?! Wow. Gosh, Lisa, I'm so sorry. Fireclay's website has a beautiful steam shower with gloss tile with crazing ON THE FLOOR of the shower. Every tile manufacturer and salesperson says not to do that - and common sense agrees - it's gloss and you'll fall on your booty! I tried to research applications on Fireclay's website because I wanted to be assured that the tile is ok. Their new Essentials line - the blog posts are clearly computer generated (same exact bathroom with different color tiles). The tile I wanted in a hotel - couldn't call the hotel because they have no phone number. Shady. Oh, and I Googled "Fireclay complaints" to see if anyone was unhappy with their crazing or the durability of the tile. No consumer complaints, but I did see a settlement with the State of California for violation of environmental regulations (i.e. polluting). That was the cherry on top for me, as SO MUCH of their literature is how good they are for the environment. Fireclay makes a truly beautiful tile. I'm very disappointed that I will not be moving forward with them. I wish they were just honest about proper applications - I'm shocked they wouldn't be. Wouldn't you want happy customers?!?!?! If there wasn't a series of red flags, I would have bought it for the whole house!

We are doing a product from Sentrel aka Flexstone. It is very nice looking and easy to work with. Our shower is 48" wide by 34" deep (the pan). We got the 96" tall panels to go to the ceiling and their 48" by 36" kit along with their upgraded niche with a shelf and corner seat. The corner shelf came with the kit. There is also trim for the top and sides. We are only going to use the side trim and just caulk the top to the ceiling. All in with swanstone pan, new trim, grab bar, shower head and Sentrel aka Flexstone we expect to be about $2K for a DIY. They have an installation locater on the web site. Don't know how much it would be to get installed. https://www.sentrelproducts.com/ It comes in alot of different patterns. We are almost done but have been hung up by an odor from the drywall work that was done and are waiting for some sealing primer to try and eliminate it before we get to final trim and paint. They give you corner seams that you glue in place before placing the panels so that there is extra water proofing behind the corners. I have a thread that shows all the details of the kit if you are interested. https://www.houzz.com/discussions/5918286/flexstone-sentrel-panels-calacatta-white-pictures#n=9

Proper material is silicone and its to fill a proper TCNA ANSI movement joint To give you advice id need to see photos of the tub flange detail and how the walls waterproofing is tied into the flange, id want to know how the tub is ledgered and fastened and that it is also set in a solid mud bed or supported per mfg properly. Mold begs more questions, any movement at that joint is a serious concern.