Is this strictly an asthetic issue, or potential leak situation?

Although I wouldn't exactly say it's an aesthetic issue, if your shower leaks, you've got much bigger issues than cracked grout.

Bill,
What, if anything, would you do about these cracks?
Thanks for your help and advice.
Sharron

Carve out the grout and caulk them. All corners are supposed to be caulked for just this reason. No matter how many times you grout them, they're going to crack again, and there's nothing you can do about it.

What is likely to happen if the cracks are not fixed?
Get bigger? Cause some other problem?
I want to understand the implications to help me discuss with the installer, and to decide whether this is something I should fix myself if he won't.
Thanks again.

IF the rest of the shower is put together properly, it shouldn't do much. But I have a feeling that if this guy isn't willing to spend the time to caulk the corners, he probably didn't "waste" his time installing a vapor barrier behind the walls, either, which means over time, it WILL get in behind the walls and cause a problem.

Bill,
Thanks for the quick response. I'm pretty sure the rest of the shower was constructed properly with preslope, vapor barrier,etc. as I was lurking on this forum constantly and checking the work as much as I could. I'll look for the installation pics and post if I can find them. Frankly, I'm not anxious to disturb things IF they aren't likely to become worse (really, really hard to see the cracks right now) or cause problems.
Sharron

I found one photo that I think shows a liner under the metal lathe(?). It goes over the preslope and under/behind the cement board, right? If I'm right about the liner, then any moisture that gets into the hairline cracks in the grout should not cause problems, right?
(Fingers crossed)
Sharron
{{gwi:1458557}}

Bill, my guy did everything right (e.g. liner) except for caulk/grout issue, and I think he made the bad choice because of the stones we were working with (pebbles) - he had no clean line to keep open for the grout. Just so folks know that not all is lost if you discover grout rather than caulk in the cracks. I'm still cleaning out a line in the plane changes and putting caulk in, though, Sharron.

If I'm right about the liner, then any moisture that gets into the hairline cracks in the grout should not cause problems, right?

In the top right corner of your picture, you see where the studs are showing above the Durock? That should be covered with either 6 mil poly or tar paper behind the Durock. That would be your vapor barrier, which is obviously missing. I'd be concerned.

So you're saying it appears the vapor barrier didn't go up the walls as far as it should have, right? I guess then it's hard to know exactly where it ended.
The current cracks are all in the corners where walls meet shower floor, not going up the walls.
If I can get the installer to redo that change of plane with caulk, is that likely to be enough to prevent future leaks/bad smells? Or am I likely to have problems either way since I think I've read that some moisture goes thru the grout (thus the need for the vapor barrier and preslope in the first place)?
I might be confused, but what do you suggest now? Unfortunately, I was not at home when this part was done, and didn't pick up on the missing vapor barrier at the top of the durock.
While I def value Bill's expert opinion, and I know Bill that you're advising the absolute right way it should be done, I'd also like to hear from folks who had a similar situation and how it turned out (I think- actually, maybe I don't want to!)

Sharron-- youo're getting confused with the terms. What you have is a waterproof pan membrane, which should only go up about 8-10" from the floor. Above that, and before the Durock goes up, there should be either 6 mil polyethlene or 15 pound tar paper, where the bottom gets tucked into the pan membrane, and then goes all thw way to the top of the shower walls behind the Durock. This is what's known as a vapor barrier. It keeps moisture that might soak thru the tile, grout, and durock (which is NOT waterproof) from getting into the wall cavity and doing damage thru promoting mold growth.

Now, 99% of the water in the shower will SHED down the face of the tile, which is why the walls don't have to be waterproofed. But the vapor barrier should be there. And cracks in the corners could be problems if left alone.

I know you wanted to hear from others, but I wanted to answer anyway for those who might bring this thread up in a search. From here, I'll leave this thread alone.