I had a leak in my shower. The caulk on the interior of the shower had failed. I cleaned and replace the caulk, and as far as I can tell, there is no more leak.

I'm now trying to repair the water damage to the area on the exterior of the shower. I cleaned out the discolored joint compound covering (roughly in the area circled in red below) and let it dry for a couple days. I then tried covering the area with new joint compound to prep for painting, but within an hour, I saw more discoloration. (The discoloration pattern corresponds to the gaps in the curved vinyl bullnose underneath. EDIT: I added an Image 4 showing what it looks like after sanding.)

I repeated the removal and drying process again, and when it happened again, I thought I needed to do a more complete dry-out of space inside the wall. And that's where I possibly made a bad error. I cut a hole in the drywall (the green arrow in Image 1, closeup in Images 2 and 3), and I apparently cut through something that might be the shower pan liner? I wasn't expecting the liner to be immediately on the other side of the drywall, so maybe it's something else? We've taken multiple showers since and I don't see any water accumulating anywhere in this area.

Bottom line, I'd welcome thoughts on:

  1. How do I more completely dry out the leak area, and
  2. What do I need to do to repair my hole (aside from drywall patch).

Image 1: Shower exterior: Shower exterior

Image 2: Closeup of discoloration:

closeup of discoloration

Image 3: Closeup of hole in drywall:

closeup of hole

Image 4: Closeup after sanding: enter image description here

  • 1
    Image 3, is your humidity barrier, not bad, yo can replace that pice
    – Traveler
    Commented Dec 11, 2022 at 2:02
  • 1
    Image 1- insert a lath horizontal or vertical that is longer that the hole. Screw it with screws. Not you can screw the pice of drywall to it so it will hold.
    – Traveler
    Commented Dec 11, 2022 at 2:06
  • 1
    Image 2-- try to sand it off
    – Traveler
    Commented Dec 11, 2022 at 2:09
  • Thank you! After I sand off the discolored area, how long do I need to wait before building it back up? I waited a couple days last time but the discoloration came back within an hour of applying new joint compound. Does that mean there's still moisture behind here?
    – Andrew
    Commented Dec 11, 2022 at 4:26
  • 1
    got it, will give a heat gun a shot. thanks!
    – Andrew
    Commented Dec 11, 2022 at 19:21

1 Answer 1


If you use a heat gun you can accelerate the drying.

Do not hold it too close so not to create burn marks on the drywall.

It might take a while so have patience.

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