I’m actually a little paranoid about moisture since I’ve got a metal roof with foam board underneath, and I keep checking for signs of condensation. Haven’t seen any yet, but I’m not 100% convinced it’s just about the install. My attic’s got decent airflow, but I still wonder if it’s enough, especially during those wild temperature swings. Anyone else notice weird smells or dampness after a heavy rain? Or am I just overthinking it...
I’ve seen a few cases where folks with metal roofs and foam board end up with hidden moisture, especially if there’s even a small gap in the vapor barrier. Sometimes it’s not obvious—no drips, just that musty smell after a storm. Had one client who only noticed when insulation started to clump. Have you checked around vents or skylights? Those spots seem to catch people off guard more than the open attic space.
That’s a good point about the hidden moisture—sometimes you really don’t see anything until it’s already caused a headache. I’ve actually run into this with a few rental properties, especially after those long, sideways summer rains. One place had metal over foam board and we thought everything was sealed tight, but then tenants started complaining about that damp, earthy smell. Turns out, the culprit was a tiny gap right around the bathroom vent pipe where the flashing didn’t quite sit flush.
Here’s how I usually check for sneaky leaks: First, I look for any discoloration or soft spots near penetrations like vents or skylights (even if there’s no visible water). Next, I’ll gently pull back a bit of insulation to see if there’s clumping or signs of mold underneath. Sometimes just running your hand along the surface can tell you more than you’d expect.
Curious—has anyone tried using those vapor barrier tapes around tricky areas? I’ve had mixed results, especially when it comes to irregular surfaces or older roofs that aren’t perfectly flat. Wondering if there’s a better way to get a tight seal in those spots without having to redo the whole section...
Curious—has anyone tried using those vapor barrier tapes around tricky areas? I’ve had mixed results, especially when it comes to irregular surfaces or older roofs that aren’t perfectly flat.
You’re not alone with mixed results on vapor barrier tape. Here’s what I see a lot:
- Tape works okay on new, smooth surfaces. Once you get into older roofs with bumps and dips, it barely sticks long-term.
- For weird angles or rough spots, I usually recommend a high-quality roof sealant (like a polyurethane caulk) instead of just tape. It fills gaps better and flexes with movement.
- If you’re dealing with metal over foam board, watch for condensation too—not just leaks. Sometimes the moisture is from inside, not outside.
Your inspection method is solid. Running your hand along suspect areas catches more than people think. I’d add: check for rusty nails or screws around penetrations—those are often the first sign water’s sneaking in.
Don’t beat yourself up over missing a tiny gap. Even pros miss them sometimes. Roofs are just full of surprises...
Tried that tape on my old shingle roof last year—honestly, it was a letdown. Stuff peeled right off the uneven spots once the weather swung from hot to cold. Ended up patching with some cheap caulk and plastic, which held better than I expected. Not pretty, but it kept the rain out. Sometimes I wonder if all these “miracle” tapes are just hype when you’re dealing with a roof that’s seen a few decades.
