Tile – How to adhere edge of bullnose tile to drywall as trim for shower/tub surround

bathroombathtubceramic-tiletile

I'm freshening up a bathroom and replacing some bullnose tile that covered up the edges of the tub/shower surround. I am also a complete tile novice. To be completely clear, there's no tile in the shower itself at all.

I understand that the "right" way to adhere tile to walls is with mortar, but the only part of the tile that actually makes contact with the wall is the 1/4" edge of the tile so that doesn't seem like a reasonable solution here. The original contractor seems to have just used construction adhesive, and while I understand that's the "wrong" way to do it (and as you can see I definitely made a mess of the drywall prying it off), I'm honestly having trouble coming up with a better option.

Is there a "correct" way to handle a situation like this other than Loctite?

UPDATES FOR CLARIFICATION

Totally understand the need for separation and silicone grout between tiles, but I appreciate you all making sure. My question is mainly about how to adhere it to the wall though.

I should be clear that there was never any adhesive or sealant between this tile and the tub. It was simply glued to the drywall and appears to be purely decorative (i.e. not water-tight). With my rudimentary knowledge my assumption is that I should put things back the way I found them when making changes, but I'm open to the idea that this may be a bad assumption in this case.

MonkeyZeus asked for a zoomed-out picture to help picture what's going on a bit better. The previous tile covered up where the surround is screwed into the wall, and I'm just trying to replace that with a nicer looking tile. It went all the way around the outside edge of the surround, so five "strips" of the bullnose tile (up the y-axis, in along z-axis, across on x-axis, back out along z-axis, back down along y-axis). I get that might be hard to visualize, but it's already too late to photograph mine and I can't find anything similar on the internet that isn't also tiling either the shower or the wall. It is not surprising to learn that the builder engaged in some wild improv.

enter image description here

Best Answer

The correct solution leaves a small gap at both ends of the bullnose to silicone to those surfaces. The correct way to adhere the bullnose is thinset in the hollow portion of the tile but that doesn't seem totally feasible in this case, you could reattach with polyurethane construction adhesive down the center of the bullnose or something like schluter kerdifix which is a tile specific adhesive using a small 1/8"spacer to keep the tile off the two surfaces. Then 100% silicone along the gaps at the drywall and tub face