Shower leaking downstairs intermittently

[enochian]

What are all the possible causes?

The caulking looks fine.

Could it be the Moen cartridge?

Picture of shower:

https://image.ibb.co/mjCAx6/IMG_20171217_194421254.jpg

 

[Jadnashua]

Does the floor of the shower flex when you step on it? Does it have spider craze cracking? Often, it will end up leaking around the drain. If you take a level, are the edges level? If it isn't level, it can end up leaking. Is the floor outside of the shower wet at all? Any evidence along the walls, either in the bathroom or in adjacent rooms of things getting wet? Last thing, you may need to cut out some of the ceiling beneath it and look. While not as common, depending on the piping, it could be holey or cracked.

 

[Sponsor]

 

[LikeABigFriedEgg]

How do you know it's the shower and not something else that's leaking?

 

[Dj2]

How do you know it's the shower and not something else that's leaking?

You will need to find the source of the leak by opening the ceiling below.

Guessing may not work.