No waterproofing in that back wall? It will be black mold and rot.

You need the proper installation to prevent water and mold damage.

There are prefab niches that should have been installed. Fire your installer and get someone who knows what they’re doing. These stories make me so mad that bad installers cause so many problems for homeowners.

As Joseph mentioned, the Redguard looks nicely applied to correct substrate (Durock Cement Board) but without that mesh tape and thinset that will not last.

When I first saw the photo I thought for once we had a good redguard application. Then I zoomed in...

He did use mesh tape on the seams on the walls. I don't think he used in on the back niche area because I heard him say something about the way the tile lays. So the Niche area, y'all are certain that 100% needs to be redone, no matter the maintenance from me (homeowner) and it being on the backside? I am paranoid about mold so appreciate the comments. But if there is a way I don't have to have them tear it out, that is preferred. So far no one has said it will likely work?

I asked a local person about this who said it may be fine if I use something like Saigers Super Sealer? Anyone know this product? Not sure about the comment someone made about the Redgard who thinks it was too thin or something?

found the pic of how the first guy left it. We had a delay waiting for a transom window and then after two months of waiting, just decided to eliminate the window. So contractor sent New tile guy as other one went on vacation for a month.

Improper taping before Redguard application. No waterproofing in the niche. Caulk is required where planes meet...yours appear to have those areas grouted (a HUGE no-no). Nothing can be done to make a shower waterproof after it's built, proper technique and strict attention to detail is necessary from the start. It's a total tear-out and redo. Take a long look at the shower in this post, although it appears to be fine...

https://www.houzz.com/discussions/3938449/shower-autopsy-warning-graphic

Get a proper installer and start over and BTW for get the niche in a guest bathroom I leave a basket full of shower items and space for their own to take into the bathroom and take out when done. The same could be for your son. Shower niches are the place where so many showers have leaks and honestly I have no idea why shampoo bottles should be on display.

The backwall photo shows zero tape and thinset (as a joint compound) quote obviously. And no, no "Super Sealant" can or will take the place of this or the balance of the proper waterproofing. As far as the thickness of the RedGuard it "appears" good but the only way to be sure is to use a gauge and check the mil thickness. And the un-wateproofed niche is a big mess.

Your contractor will not want to hear all this and will push back telling you that it‘ll be fine, he’s never had a call back, and he’s done it like this forever. But you should have a meeting. Ask him what all the waterproofing steps were and take notes. Post what he says here. It helps if you have more in-progress photos. Document all the notes from your meeting by summarizing and following up with an email to the contractor. If it’s not waterproofed right, no sealing or caulking that you do will change that for the long term.

@Karen Rod - Seek your new tile Pro reference from a real tile shop. Real tile shops do not have pallets of tile/tools/grout...just tile and maybe woods. The Pro you want to hire will be 6 weeks out and he won't come cheap. A great tile Pro has the eye of an artist and the skill of a surgeon.

I would also go online and check youtube videos about how to install bathroom shower tile. When you are in the know, there is no question.

You can go down a rabbit hole of misinformation if you go on YouTube to learn shower waterproofing and tiling. I did look at Sal Diblasi’s online videos. I stopped there because there’s a lot of bad info out there. Also look at the John Bridge forum.