The grout needs to be completely taken out and a very good quality caulk put in. I too, wonder about the quality of the water proofing, since a reputable tile person would have known to caulk.

The photos with discoloring indicate subsurface moisture. Orange bacteria in my area is an indicator of excessive moisture.

Your shower maybe a remove and replace.

As others have said, grout was the wrong material to use. Change of plane or change of material = caulk. Remove the old grout, clean the surfaces well, allow to fully dry, and use a good quality 100% silicone caulk.

Excessive moisture may just be an indication of poor ventilation, not necessarily installation. If you have a exhaust fan, make sure you are running it for 15-20 minutes after you shower. Sometimes adding a timer makes this more convenient to do. If you don’t have an exhaust fan, think about adding one.

Thank you everyone for your replies @live_wire_oak @cat_ky @User @mike_kaiser_gw.

I don't have an exhaust fan but after showering.. i open the window and leave the bathroom door open as well.

Do any of you have any recommended products for the caulk and the dremel? I'm assuming i have to use the dremel to remove the grout.

I've never done grout/tiling work but want to learn more about what to do just in case if i try to tackle it on myself or if I need to "double check" the work of another (hopefully not shotty) contractor.

Thank You everyone!

"Shotty"? Is that a cross between "shoddy" and the nastier word that rhymes with "pity"? :\

You really ought to find out what's behind that tile. It might be good insurance for the future of your place's structure to open up a couple square feet of wall from behind, in the next room over, and have a good look. If everything looks nice and dry, just close it up. If you find dampness, possibly mold and/or the beginnings of rot, this might be a good time to have a little chat with your lawyer about your options.

As David suggested it might not be a bad idea to open the backside of the wall and see what you have. Assuming it’s drywall, it’s not difficult to patch.

As for removing the old grout, there’s several ways to do it. The cheapest is a grout saw, available in any Home Depot for $10 or less. Just requires more elbow grease but is the easiest to control. I might be inclined to use an oscillating tool and a carbide grit blade meant for grout removal. A Dremel would also work, maybe invest in their little grout adapter to help control depth of cut.

The enclosure should be waterproof without the tile and grout. The caulk is a decorative accommodation to mediate the different planes of movement. Without a flex joint, the hard joint filler will continue to come out. In other words, time and the change of seasons will allow most of it to remove itself without aid. I’d wait for another season’s change and plan to do this in late spring.

Also take the opportunity to have a ducted bath fan added. 100% of topical mold and mildew issues are attributable to insufficient ventilation.

While a vented bathroom exhaust fan might not be possible in your building, you might want to consider a small table top type fan on the floor, in the doorway, that will move the air around to help facilitate faster drying. Better than nothing.

This is what we use in the summer

Thanks everyone for your replies. I guess i'll start watching some DIY videos for a while and try to tackle it myself. Hopefully it's not that long.

I just plan on doing those two lines from the connecting panes of the walls.

If you have a curb, you will have the cracks develop there, too. and where the walls meet the floor. Anywhere where two different materials meet or where one surface meets another that is in a different direction (known as "change of plane").

My contractor still grouts such places, too. But I did a solid surface shower that he could not do wrong. I am keeping an eye on the place where the floor meets the shower pan, all other places are in dry areas. So there it is just cosmetic.

I would guess that water can get behind your tile with those cracks. If properly waterproofed it is fine, but if not, I would get to this as soon as you can. A lot of shower builders do not use waterproofing, even though it is now required. If you do a search on this forum for "Shower waterproof," you can see many discussions about it and learn what is and is not waterproof. (Redguard yes, Durock no, for instance.)