finally found an underlayment that lasts - what's your experience?

Interesting you mention using peel-and-stick just on the eaves and valleys. I’ve always wondered about the long-term impact on the decking where it’s applied, especially with how aggressive that stuff is to remove. Have you ever noticed any extra rot or mold where the peel-and-stick was, compared to areas covered with synthetic? I’m always a little cautious about anything that doesn’t let the roof “breathe,” especially on older homes or those with less-than-perfect attic venting.

I get the appeal in heavy snow zones - ice dams are brutal - but sometimes I wonder if we’re trading one problem for another down the line. Anyone ever try one of the newer “eco” underlayments that claim to be both waterproof and vapor-permeable? I’m curious if those actually hold up in a real winter, or if it’s just marketing hype.

I’ve pulled up a few old peel-and-stick patches on my uncle’s place, and man, that stuff clings like it’s holding a grudge. Didn’t see much rot, but the wood underneath felt a bit “sweaty” compared to the synthetic spots. Haven’t tried the eco underlayments yet - still a little skeptical, honestly. The idea sounds great, but I’d love to see how they hold up after a couple of freeze-thaw cycles.

I get the hesitation with the eco stuff, but honestly, I’ve had more trouble with the old-school synthetics getting brittle after a couple winters. The “sweaty” wood thing bugs me too - almost makes me wonder if peel-and-stick is trapping more moisture than it should? I’m in the Midwest, so freeze-thaw is a big deal here. Have you actually seen any of the eco underlayments fail, or is it just a gut feeling?

The “sweaty” wood thing bugs me too - almost makes me wonder if peel-and-stick is trapping more moisture than it should?

Yeah, I've seen that sweaty wood issue crop up, especially on low-slope decks with peel-and-stick. In my experience, it’s not always the underlayment’s fault - sometimes it’s ventilation or the deck itself. Haven’t seen the eco stuff fail outright, but I’ve only used it on a handful of jobs so far. Midwest freeze-thaw is brutal, though. I’d trust your gut and keep an eye on it if you’re trying something new.

I’m always wondering if it’s the underlayment or just my old house breathing weird. I tried peel-and-stick on a porch roof and yeah, got some of that sweaty wood too. Is it worse with OSB than plywood? Or just bad airflow? I’m in the Midwest too, so winter’s a beast...