Rip that out and install new, correctly. You can’t tile on that.

Can you please explain? im not sure what you referring to when you say to rip out, the entire tile backer board? this one is specifically for tile installation, residential wet, it says right on it.

What is the black on the board? Waterproofing?

You can tile over the joint between backer board and gypsum board at the top as there's a slim chance water will get to there. However I see a few other problems; the backer board should overlap the tub flange, the joints in the backer board should have thinset applied to them, not drywall compound, and (just guessing) I assume there's no waterproofing behind the backer board. There should be polyethylene sheet behind the board and over the flange or one of the modern surface applied waterproofing like Red Guard.

Hello, I think he just installed that board to the studs. the joints, I applied caulking as to seal it up as spiders and bugs were coming in...Yes, I researched that and saw mine does not overlap the tub flange...shoot...i dont know why he did that. My husband said he had a reason why when he did it.

Giant fail. Remove and start over.

@User thank you, real constructive...NOT!

If you just tile it as is, it will be better than many installations. However, I would remove as much of the drywall mud that will be in wet areas of the tile before you start. Drywall mud turns to mush when it gets wet.

@Seabornman thanks for the response. That is caulking on there, no drywall mud. Also, toilet paper to temporarily plug around the fixtures so bugs didn’t come in. Was going to add additional backer board to the top...we paid a lot of money for the tub and shower tile to be torn out and this installed.

That looks nothing like an installation of waterproofing pursuant to codes. Have you searched for threads in the Bathrooms forum about correct waterproofing of showers? All the information you need is there. Please read a big number of them, and don't waste any more money with this looking like this. You need to read up on correct waterproofing.

The reason the pros comments are sounding terse to you, is that this type of question is asked so much, that it gets old to re-explain, and re-explain the principles of waterproofing and to point out the errors. I think you will be glad (later) that this is pointed out to you at this stage, rather than after you tiled, etc. Whoever put that stuff on your wall is probably unqualified. I believe the guidelines they need to follow are TCNA. So, you can find a new person to do the work who is veeeeeery familiar with those.

I didn’t look up waterproofing because I hired someone who is licensed and had all 5 star reviews so i guess i assumed they knew what they were doing. If I knew how I would have done it myself. No one in this forum mentioned what the actual problem was besides the flange or asked me what materials were used, just to tear it out.

I think I’m going to seal up the edges with the mesh or sealant tape and be done with this. thanks everyone for input.

"I applied caulking as to seal it up as spiders and bugs were coming in"

Yikes.

@JC, I totally understand what you're expressing here: "I didn’t look up waterproofing because I hired someone who is licensed and had all 5 star reviews so i guess i assumed they knew what they were doing. If I knew how I would have done it myself."

From seeing numerous tile fails in this forum, I've learnt that the key to a successful bath reno is the waterproofing system. Tile and grout aren't waterproof. Here's a YT video from Home Reno Vision DIY that goes over 4 waterproofing systems for a bathroom. Jeff is an Ottawa-based contractor with over 30 years of experience. His stance is pick one system and follow each step to the letter. Not a super short video so I choose the 1.25 playback speed to save a bit of time. Annoying that homeowners need to learn the correct build methods before hiring Pros but it seems essential. Good luck!

If you move forward with that, you will be funneling water into your walls. It won’t last a year. And the damage will be extensive. The backer must overhang the tiling flange, with correctly integrated waterproofing. That has none of those things. The caulk will only make things worse. It is not an acceptable installation at all. You must remove it all and start over.

This house was built in 1991. in the neighborhood, the contractors just stuck the tile to the drywall, no waterproofing at all, zero. So, there was some mold beneath the tiles on the bottom 1/3 of the shower wall at the back and the right side. thanks for the comments from those who were respectful. the others, i just dont think it is right to make of people..there were openings and it has been this way for months so naturally insects could find their way in, so i applied caulking, how is that yikes?! i will sort it out, look like it has to be moved further down and i will keep thise other tips in mind, too.

Caulk on a temporary basis is ok. However those joints are required to be taped with a non-alkaline mesh tape and spackled with thin set with waterproofing then applied over the top.

I've ripped out dozens of 30 year old tubs with tile walls. Not one of them was built the "right way", and rarely has there been any damage. The tub is waterproof, the walls will be water resistant with cement board, thinset, and tile. You can paint on some liquid caulk (Red Guard). Ignore Josephine, she's been banned here numerous times under different aliases.

You can choose to listen to those who are experts on this forum even if they're a bit harsh in how they say what needs to be said, or you can listen to people like Ksc who obviously thinks it's ok to do things improperly because to quote, "rarely has there been any damage."

I personally don't want to be one of the rarely's. I'd rather do it right the first time so I don't get mold, etc like you had with your poorly done shower. This time you may get another 30 years out of it, or you may wind up having to redo it in a year or two if you do it incorrectly. Seems to be quite expensive to have to redo every couple of years.

Most people don't want to live with mold inside their walls.

JC. Most commenters above see USG in your photos and relate to USG cement board. Which is not what you have. The following from manufacturers site.

USG Durock™ Glass-Mat Tile Backerboard is a water-resistant, easy to use panel for walls, floors, and ceilings. Durock™ Glass-Mat Tile Backerboard consists of a treated water-resistant gypsum core that is covered with a coated fiberglass mat facer and back and has a proprietary surface making it ideal for use in wet areas as a tile substrate. Durock™ Glass-Mat Tile Backerboard combines the tile bond of cement board with the handling and ease of use of a Sheetrock® Brand panel.

Contact USG directly for installation instructions would be my recommendation.

As for the tub flange. Is there a return flange that goes up behind the board? I believe there may be. If that is the case there are no issues here as the tile will end on the top exposed tub splash. It appears to stand proud enough all the way around to accommodate the thickness of tile. If there is not a flange behind the board then full stop. This detail needs to be established before providing any advice.

@Creative Tile Eastern CT thank you for the information. I don‘t believe there is a return flange, I could be wrong, but I don’t think so. I tried looking up a photo of the tub online: Brand: Duravit

Architec 60" Alcove Acrylic Soaking Tub with Right Drain and Overflow

Model:700355000000090, I may have to go look more closely.

I believe before I applied caulking it just appeared black behind there, like into the opening behind the wall. i texted the contractor today to ask why and he said he prepped for a float system...if the walls are floated before tiled it works, I’m unsure what that means. Thank you

I'm just a homeowner, not a pro. But I do know that if your shower is not properly waterproofed it will cost you more bc you'll have to tear it out and redo it probably pretty soon. My tile pro told me that you can actually take a shower (in a properly waterproofed shower) before the first tile is even placed. I didn't know this before he explained it. The reason is that the waterproofing is all the stuff that is underneath the tile. Tile and grout are not waterproof. Like most things in life, the preparation is the most important thing: cooking, painting, building a shower, the list goes on and on...

Pretty soon? The OP claims their old shower/tub was 30 years old, with tiles over sheetrock and zero waterproofing.

@josephP proceeds to show a non compliant diagram LOL. @houzz

@josephP "proceeds to show a non compliant diagram"

@Mint tile Minneapolis: Could you explain what's non compliant about the diagram, please?

ksc36

OP said this:

"So, there was some mold beneath the tiles on the bottom 1/3 of the shower wall at the back and the right side."

...30 years later. I'm sure if you hired a mold specialist they would find mold in every bathroom. I'm not advocating improper installation, it just isn't the catastrophe ignorant houzz's make it out to be. 30 years, sheetrock....