Hi all, I'm collecting a list of issues that are popping up around the house, and looking to find time this month to take care of these - hopefully myself. I'm not a handy person at all, but I'm trying to take care of these projects myself to learn. We have stone tile on our main floor, and I'm starting to notice the grout is coming loose and apart. A few of the main issues is at the bottom of the staircase - you can see the grout is either missing, or loose enough to pull out. I'm wondering what the best way to repair this, and if I should actually use group to repair it - or the caulk type material? Here's a picture for reference, but what would you think is the best (and maybe only) way to repair? Thanks all, appreciate the responses. Rob

[B][U]Background[/U]:[/B] The tiles in my shower around the faucets were cracked and glued back to one another in that area around the faucets. So they leak water to the next floor causing damage. Upon removal of these broken tiles, it appears a piece of drywall is was removed behind these tiles in the space around the faucets and up. I think a chunk of the drywall was removed from behind during some plumbing work at some point, and now the tiles have nothing to properly adhere to so they leak/crack. I just need to repair this long enough to have a working shower while my other bathroom is being renovated over the next year or so. It doesn't have to be perfect, but I can't have water damage from it. I will eventually renovate this one too, but after the other is done. [B] [U]What I've done so far[/U]:[/B] I have removed the rest of the tile and drywall on that side of the shower with the faucets. I patched the new piece of greenboard in where the missing drywall was, screwed it to studs, and mudded with 20 min hotmud/fiber tape. It came out solid! When I redo this bathroom, I will do all cement board, but for now, I used greenboard to match what is already around it so lets not argue this choice. [B]Here is where I need help...[/B] (1) To start, what kind of adhesive should I use for the shower tile? Thinset, though not as sticky as mastic seems better in showers but I hear tiles can slide... what do you do about that? If I go with thinset, what kind should I get? (2) Should I start from bottom and work up with tile, leaving a 1/4" gap for caulk and prevention of water wicking? Sound right (3) I will have more questions, but any other pointers/suggestions at the point I'm at? Thanks!!