Said It Here

Ceiling drywall bubbling after rain above the shower

Bubbling drywall and failing patches after a rainstorm usually indicate a roof leak, often caused by a failing plumbing vent boot. This traps moisture behind the paint and prevents simple patches from adhering, meaning the exterior roof penetration must be fixed before repairing the interior ceiling.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    Attempting a patch with normal paper tape and mud
  2. 2
    Inspecting the attic for nearby plumbing vents or roof damage
  3. 3
    Cutting out the damaged drywall to inspect the area
  4. 4
    Climbing onto the roof to inspect boards and look for water entry points
  5. 5
    Calling a roofer to inspect and potentially replace decking

In their words

Unedited, most upvoted first, each linked to the thread it came from.

About a week ago I noticed a small bubble in the ceiling above my shower. Poked it and discovered this little hole in the drywall (couple inches).source ↗

I attempted a patch with normal paper tape and mud. It seemed ok for a few days until a rainstorm last night. My "repair" was all bubbled up.source ↗

Deadite_4_Life · r/HomeImprovement · 3 upvotes

I had this same problem, and it was a plumbing vent with a failing boot around it (on the roof).source ↗

binarycow · r/HomeImprovement · 1 upvotes

I cut a patch out of some drywall that was showing a wet spot, it would happen during heavy rainssource ↗

Own-Assistant7441 · r/Roofing · 1 upvotes

Where this came up

People with this problem also raised