I insulated my shed roof under EPDM a few years ago, thinking it'd be the perfect solution for temp swings. To be fair, it did help with the heat, but moisture became a bit of an issue. Nothing catastrophic, just noticed some dampness on colder mornings and a bit of mold starting to creep in around the edges after winter.
I think the key is ventilation—it's easy to underestimate how much airflow you actually need. I thought a couple small vents would do the trick, but clearly not enough. Ended up adding some extra ventilation later on, and that seemed to sort things out.
Makes me wonder though...is EPDM more prone to trapping moisture underneath compared to other materials? Or is it just about how well you ventilate regardless of roofing type? Curious what others have experienced.
I've been wondering about EPDM myself—seems like a solid choice durability-wise, but moisture buildup is something I hadn't considered. Maybe it's less about the material itself and more about how airtight it ends up being? I'm planning to redo my garage roof soon, and now I'm second-guessing EPDM. Has anyone found metal roofing better at handling moisture and ventilation, or does it have its own set of issues?
"Maybe it's less about the material itself and more about how airtight it ends up being?"
Exactly—ventilation makes or breaks it. Metal roofing handles moisture pretty well, but condensation can still pop up if airflow isn't dialed in. Just make sure your vents are solid and you'll be good.
"Just make sure your vents are solid and you'll be good."
Good point on ventilation, but I'd add a couple caveats from experience:
- Metal roofing is durable, sure, but it's not bulletproof against extreme weather. Seen plenty of cases where high winds peeled back panels—especially if installation was rushed or corners cut.
- Agree airflow matters, but don't underestimate seal quality either. Even tiny gaps around flashing or fasteners can let moisture in during heavy storms. I've seen roofs fail because someone assumed the metal itself was enough protection.
- Also worth mentioning: hail damage. Metal roofs generally hold up better than shingles, yeah, but large hailstones can still leave dents or compromise coatings. Had a client last year who thought his new metal roof was indestructible... until golf-ball-sized hail rolled through.
Bottom line—no single solution covers everything. Good materials + proper install + regular inspection = best bet for wild weather.
Good points overall, but I'd push back a bit on the hail concern. Yeah, metal roofs can dent, but in my experience those dents are usually cosmetic rather than structural. Had a pretty nasty hailstorm two years ago—roof looked like a golf ball afterward, but zero leaks or real damage. Insurance adjuster even said it was mostly aesthetic. Still, you're spot-on about installation quality...seen way too many "bulletproof" roofs fail because someone rushed the flashing details.
