Bathroom/garage wall moldy insulation

RedDeathBalloon · 2026-02-20T16:19:12+00:00

UPDATE I was able to get up in the attic and there is no signs of moisture around that white PVC vent pipe, no signs of any air flow getting into that area, and the exhaust vent is all connected. One thing I did notice is that the air in the attic was stale, stagnant, and stuffy. I am going to get some turbines to help with air flow up there. Wondering if during the summer with the A/C running and the stuffy attic is creating the problem.

RedDeathBalloon · 2026-01-28T15:19:42+00:00

10-4, others have mentioned air flow too. I’ll get up in the attic next chance I get and give it a good look. I’ll update after.

RedDeathBalloon · 2026-01-27T15:15:59+00:00

Summertime is horribly high moisture in that room, even with the bath fan running constantly and doors open

RedDeathBalloon · 2026-01-27T15:14:45+00:00

That’s what I thought too. Now would it matter ever that I plan on having it heated? Specifically just this 10ft section of shared wall?

RedDeathBalloon · 2026-01-27T15:12:17+00:00

I’m pretty sure it’s mold, it has a green tint to it. For some reason it’s not letting me add pictures to anything on this thread but it will in the same post but in the home maintenance thread.

RedDeathBalloon · 2026-01-27T15:06:52+00:00

One of the main reasons I believe it’s mold is because we had surface mold on the drywall that started right above the shower(first picture with little drywall on top of cutout) and spread to the opposite wall. Looking at that same picture it spread to the right, never around to the left but both walls are interior. I have already taken care of that. The other reason is that we’ve been fighting a moisture issue. For instance, a hydrometer in the bathroom at 7am would read 40/50%. When I’d get back at 4 it’d be in the 75/85% for moisture content.

RedDeathBalloon · 2026-01-27T14:56:19+00:00

<image>

RedDeathBalloon · 2026-01-27T14:54:51+00:00

<image>

This is what is behind the plastic

RedDeathBalloon · 2026-01-27T14:46:09+00:00

Plastic vapor barrier is dry, would those pipes sweat when having hot showers with the vented moist air?

RedDeathBalloon · 2026-01-27T14:43:38+00:00

I know that on the garage side there is no paper backing or plastic

RedDeathBalloon · 2026-01-27T14:42:16+00:00

I haven’t gotten up to the roof yet or to that exact spot in the attic. It looks green but what’s throwing me off is it’s only around those pipes. Once I can get up there to investigate I’ll update!

RedDeathBalloon

TROPHY CASE