Crack in shower wall

In My Humble Opinion
1

I went to take a shower this morning, and discovered a crack in my shower wall.

I’ve already left a message with my plumber, but his hours are Monday - Friday, so I don’t expect to hear back from him for a couple of days. I’ve also contacted my insurance agent.

I’m looking for opinions on what this might be, as I know nothing about this stuff. When I press on the wall around the crack, I can tell there is something behind the fiberglass causing it to bulge out. Which apparently broke through. I gently pried the crack open a bit, and I can see there’s a stud right behind the crack. There’s also what looks like battery corrosion (the bulge). There’s no way to get a picture of this, though.

My theory is that a nail has worked its way loose. Which means the stud is waterlogged. I’m hoping against hope that someone will tell me I’m wrong, that I’m worrying over nothing…

In case it’s relevant, in the past we’ve had issues with water leaking from the bathroom upstairs. We had the issue fixed, and there hasn’t been any leaks in years. About a year and a half ago, we discovered a bunch of water damage beneath the tub in the downstairs bathroom. We were told by the restoration company that came out that it was a combination of cracks in our bathroom floor tile, and the previous leaks from upstairs. We had the whole bathroom remodeled, and we were assured everything is all good. There’s been no issues with water leaks since, that we’re aware of.

2

I wonder if it’s expanding foam insulation (ie Great Stuff). They may have filled the stud bays with it to keep the shower walls from flexing. I know it’s done under tubs so they don’t move when you’re standing on them, I’m not sure about the walls though.
Some expanding foams do get turn an ugly orangeish/rustish color after a while.

Can you get in there with a screwdriver or something to pick at it with? You’ll probably be able to get a better idea of what it is, even just based on the feel/sound and what it looks like if you can break the top layer off of it. Or, at least, if it’s foam insulation, it’ll be more obvious.

3

Also, is that an interior or exterior wall?

4

It’s the fiberglass shower insert, inside the shower.

5

But what’s beyond it? Another room or outside?

6

Oh! This is a townhouse. The other side of the wall is the neighbor’s bathroom (and shower/bathtub, I would assume).

7

Interesting! Wonder if something is up with your neighbor’s plumbing? I once lived in an apartment in a building that wasn’t quite level, and there were a couple of times when I found water that had originated from leaks in my neighbor’s apartment.

8

There is no repair for this.

You are looking at a complete redo of the entire shower, after correcting the issue behind it.