I've tiled my own two bathrooms and my kitchen backsplash, so when my adult daughter's shower sprung a leak at her "new" (circa 1950) home, DH & I came to the rescue. Ripped out the whole tub surround (it gave up without a fight), fixed the plumbing, reinsulated, added backerboard, taped, mudded and commenced to tiling. Got complicated around the tub; being an old steel tub, it has about a 1" flange around the top edges as though it's supposed to bolt to something? We ran the backerboard down to within 1/4th" of that flange, did the tape /mud/dry time thing and then commenced to tiling. When I got to the grout, I must say, the grout was a tad drier than I'd liked for it to be, but I worked quickly and thought I'd done okay. We spaced the bottom row of tile to cover that backerboard/flange gap, which it did okay. Then I left my daughters to finish grouting the normal 1/4th gap around the edge of the tub. I would have used caulk, but since the gap varied some, the girls used the regular grout to finish off that bottom edge and the corners. Are you with me so far? It looked really nice. Now I notice a lot of little tiny cracks in the grout all over and I'm thinking I'll be okay to just smash in another coat of it. (She hasn't used any tile sealer, yet.) EXCEPT.........she called tonite to say the whole bottom row of that grout is soaking wet, coming out in big soggy clumps and some of the tile with it. My thoughts are that she didn't let the tile cure enough before going in and using it, so now we need to pull out all the soggy stuff and redo it from there. So, the questions are: did we handle the backerboard/tile/grout around that flange right? Or is there just enough movement in a steel tub to disallow a grout (vs caulk) to flex. If that makes any sense.......And the second question is: am I on the right track to fix it? How long does it REALLY take for tile to cure enough to take a shower? Please tell me I don't have to take down this whole job.....this is a single mother with a TEENAGE daughter who will just DIE if she doesn't get to shower. Thanks for reading this far............. mm

Is the Platinum the Laticrete Platinum? If so what about Silver Shadow? It is a very soft gray that is almost white, but looks great with Platinum. Are you using cementitious grout or epoxy? I know many have used SS for their light or white tiles. Here is Silver Shadow epoxy on the bottom vertical grout spaces. The top area was grouted with a 50/50 ratio of Platinum and SS. The middle row was with Raven and SS. Note that there is a halo around the marble, like it is still wet. Epoxy can do that with marble, I just looked at my tile boards after over a month of drying and the halo is still slightly there with the darker grouts. But not as marked as in this picture. So that is something to consider. Here is the Silver Shadow epoxy with my bright white tiles. With these tiles the SS looks light gray, but with the tiles above it looks almost too white for my taste: I took Laticrete epoxy Platinum and mixed it with a little bit of Silver Shadow for an in between gray for my black slate floors. It is in a 3:1 ratio. The colors mixed very nicely. The grout sample on the left is the SS and the one on the right is the Platinum. It didn't take much SS to lighten it up significantly. If I did this over I would just have used Platinum. My DH really likes the combo. He thinks it ties in with the tub. It is relative isn't it, because it is not white at all but appears white. I will be having a marble listello, as seen above in the sample board, with my white tile wainscot. I might mask the marble off when I grout the white field tile with Silver Shadow. Then I would plan to come back and grout the marble with a reverse blend of Silver Shadow 3parts to Platinum 1 part. Nothing like trying to complicate things. That's one of the benefits with DIY. But if I was paying someone to grout, I would not consider these mixes.

Since the cracks are purely cosmetic you can use caulk to cosmetically fill the cracks. Do a small test to make sure the caulk visually meets your goal.

@ci_lantro I agree, the blue grout is not the right color blue for the tile. Re: floor tile, the floor in the picture in the unfinished concrete floor, ha! However, I am using Basic Cement Silver Porcelain Tile (Tile Bar) which is the same thing as Ivy Hill Essential Cement Silver Tile Porcelain (Home Depot) to tile the floor, and it looks very similar to concrete. The floor tile is actually the backing for the samples, so you can see that it is a silvery cement looking tile.