Also...just to note...I read through all of the similar questions I could find on here, and none of them specifically addressed the top of the tile being open against the wall.

I am confused where the close up pic is. Can you back out a little and show a penny or dime for scale? If at the very top, ? seal with a clear silicone caulk ?

Agh. My last comment didn't post. But yes. The close up pic is a picture of the gap at the top of the tile against the wall. It is about 3/4 inch wide. I can fit my whole fingers in there with room to spare. I'm at work so I'll try to take better pics later, but this is another angle of the gap along the top of the long side of the shower.

I'm new to this...but seems a bit wide for just caulk. It would be A LOTTT of caulk to fill that gap. Sorry for the newbie questions!

I *think* I understand what is going on now.

Looks like there is a small gap between the drywall and the foam tile backerboard. Caulk that gap with a good paintable caulk. Big Stretch or Lexel, both available at Lowe's or Amazon. Then prime and paint with a good quality mildew resistant 100% acrylic paint.

The white topper tile is a crown tile and what you're calling a gap is really a ledge??

Appears that the foam backer was installed over drywall creating the ledge.

After you caulk and paint, you should keep a close eye on it for any developing problems with condensation running down the wall. Water won't be a problem for the foam backer board but could cause problems at the seam between the drywall and backer board. Make double sure to do a meticulous caulking job with no gaps. Tool the caulk smooth and with a rounded cove.

Did you inherit any left-over matching tile w/ the purchase of the house? How much? Enough to remove the crown tile and tile to the ceiling? Can you buy more of the tile to have on hand in case you need to tile to the ceiling? (If you have leftovers in a box w/ the info you need to match.) Or get that info from the former owners?

Another option would be to add another layer of dry wall over the shower area to eliminate the ledge. Use J-Bead on the visible raised edge of the drywall. And L-Bead where the drywall butts up to the foam backer board to stop any capillary action of condensation wicking into the drywall. Caulk, etc., there, too.

What does the side look like? I'm not understanding how there's a gap at the top and not at the side...

They filled in the same gap/ledge on the side already. It's filled in with something and topped with painter's caulk. If you look at the picture that shows the front view of the shower, and zoom in, you can see a slightly yellowed area on the side running vertically down the wall where they already filled it in & caulked. Except I wasn't the owner when they did that.. so I wasn't sure what they used or if I needed to do the same thing along the top.

ci_lantro, thanks sooo much for your advice. I think you are exactly right. It feels like a ledge, like I could wrap my fingers around the back of that crown tile at the top and just pull the whole thing down (if i had superhuman strength of course.. lol).

It's a pretty big gap, probably 3/4 to 1 inch in width (between the top edge of the crown tile and the wall). Would I need to fill it with backer rod or anything before I attempt caulking such a huge space?

They finished & caulked the sides but I wasn't sure if I needed to do the same thing at the top because of the way water might collect there from condensation on the wall or ceiling. Wasn't sure if I would need the same materials.

I would love to tile all the way to the ceiling. It would look so much better and be easier to keep clean. I will have to ask the prev owner if they know what tile was used.

Okay..now it makes sense.

Before worrying about the gap, which is totally fixable, I would worry about the stability of the top row of tiles. They really should be affixed their entire width (top to bottom as shown) in order to be stable.

Fortunately, they won't be subject to pressure so that's a plus. Unfortunately, they will be subject to pressure at the sides (people will lean on them occasionally) so here's hoping that the backing is bigger along the sides than the top...you can tell by looking at the corner.

How much of the width top to bottom do you think is unsupported? Are they four by eight inch tiles?

cat_ky, yep, it was inherited from the previous owner. I am hypervigilant about mold so I will definitely keep an eye on it. That is part of the reason why I was so worried about this top edge.. I don't want anything "unsealed" before I really start showering in there. The home inspector did tell me that there was a whole new subfloor under the bathroom... so that's either good or bad depending on how you look at it. haha. Good because it's a whole new floor so hopefully that means they did things right... OR bad because they NEEDED a whole new floor.

Mel, No, not gobs of caulk up there. Just caulk in the very small gap between the foam board and the drywall. So water doesn't trickle down between the foam backer board and the drywall. Then paint and keep an eye on it...for water damage to the drywall.

I was wondering how the side was done and you've explained that. Lots of caulk.

With that new info, I would look at 'chair rail tile' and see it the part of the tile that returns to the wall is sufficiently deep to 'cap' the edge of the backerboard.

Or you could remove the crown tile and 'frame' around the tile with a build-up of PVC trim mouldings.

Thank you so much. So you don't think it will be a problem if the top edge of foam backerboard is still exposed, as long as I just caulk the space where the drywall meets the foam (And watch it!)?

All of your other ideas are fantastic too. I hate feeling like it's "unfinished".

For what it's worth, they did a really good job with the gap on the sides, it's very clean and looks neat and professional.

@pennydesign, I really don't think much, if at all of the sides are unsupported. ill have to take a good look at the top corner tonight, though, to see how far out the foam backer board extends.

I don't see why you couldn't continue this to the ceiling if you wanted to...

Probably the tile was purchased locally, so you could take a quick look around at subway tiles..

I wouldn't worry too much about using the shower and water getting in there in the mean time. You would have to use it for years before it became a problem imho...Use your fan and take a peek at what happens after you have a shower.

So you don't think it will be a problem if the top edge of foam backerboard is still exposed, as long as I just caulk the space where the drywall meets the foam (And watch it!)?

No, water isn't a problem for the foam. Caulk it and then paint over the drywall where it looks like it isn't painted. Or prime, caulk, paint, in that order. It's the drywall that needs the protection.

And, yes, do keep a watch.