That’s the thing—metal roofs are great until you realize they’re basically giant condensation magnets if the attic isn’t dialed in. I’ve seen folks spend a fortune on fancy vent systems, only to end up with more moisture problems than before. Sometimes less is more, especially if you’ve got good air sealing and insulation. Out of curiosity, did you ever try adding any rigid foam above the roof deck, or just stick with the vapor barrier and call it good? I’ve seen that make a difference in some of these damp climates, but it’s not cheap.
- Rigid foam above the deck can help, but yeah, it’s a pricey upgrade.
- I’ve seen folks skip it and just rely on a solid vapor barrier, but sometimes that traps moisture if there’s even a tiny leak.
- Curious—did you notice any difference in attic temps after your changes? Sometimes adding foam shifts the dew point enough to matter, especially in humid spots.
- I’m still on the fence about whether the extra insulation up top is worth it unless you’re doing a full re-roof anyway...
I went back and forth on the rigid foam too, mostly because of the cost. Ended up skipping it and just beefed up the blown-in insulation, plus a vapor barrier. Honestly, attic temps didn’t change much, but I did notice less draftiness in the bedrooms. Still, I worry about moisture sneaking in... especially after last winter’s ice dam mess. If I ever have to re-roof, I might rethink the whole setup.
Honestly, I get the hesitation with rigid foam—pricey for sure. But in my experience, skipping it can bite you later, especially with ice dams and moisture creeping in. When I switched to metal roofing with exterior foam, the attic stayed way drier and the ice dam headaches disappeared. Might be worth considering if you’re already thinking about re-roofing down the road... sometimes the upfront hit saves a lot of hassle later.
I get where you’re coming from, but I’ve had decent luck without exterior foam—at least in my climate (upper Midwest, lots of freeze/thaw). I went with a high-perm synthetic underlayment and good attic ventilation when I replaced my shingles with metal. Haven’t seen ice dams since, and the attic’s been dry. Not saying foam’s useless, but for folks on a budget or with decent roof pitch, there are other ways to tackle moisture and ice issues without that extra cost. Just my two cents from a few rough winters...
