Marketing makes it sound like synthetics breathe, but when you dig into the numbers, most are way tighter than felt.
Yeah, that’s what tripped me up too. I always thought “breathable” meant, you know, actually letting moisture out. But when I checked the perm ratings, synthetics are like plastic wrap compared to felt. I’ve slipped on that stuff more than once—especially on a cold morning. Anyone else notice felt gets wavy if it’s humid, though? Not sure which is worse: a slick synthetic or a wrinkled felt under shingles...
That’s the thing—felt gets all bunched up for me too, especially after a humid night. I’ve had to smooth it out more than once before laying shingles. But then again, I’ve seen some synthetics just shred in high winds if they’re left exposed too long. Has anyone tried those newer “breathable” synthetics? Curious if they actually handle moisture better or if it’s just more marketing talk...
Breathable synthetics are a mixed bag in my experience. They do handle moisture better than old-school felt—less wrinkling, and they dry out faster if you get caught by rain before shingles go on. But you’re right about wind. If you don’t get them nailed down tight, or if you leave them exposed for more than a few days, they can tear up just as bad as the cheap stuff. I’ve had better luck with the heavier grades, but they cost more. Honestly, nothing’s perfect, but I’d take a good synthetic over felt in humid weather any day. Just gotta watch the install and exposure time.
Honestly, nothing’s perfect, but I’d take a good synthetic over felt in humid weather any day. Just gotta watch the install and exposure time.
You nailed it—install and exposure are everything with synthetics. I’ve seen jobs where folks left them uncovered for a week and came back to shredded underlayment flapping in the wind. But when they’re put down right and covered up quick, they really do outperform felt, especially in muggy climates. The heavier grades are pricey, but sometimes that extra cost pays off in peace of mind. It’s all about balancing your budget with how much risk you’re willing to take on weather delays.
It’s all about balancing your budget with how much risk you’re willing to take on weather delays.
That’s the truth. I’ve had a couple projects where the crew swore they’d get shingles down before the rain, but you know how forecasts go... Ended up with soggy felt and a lot of finger-pointing. Since then, I stick with synthetics for anything bigger than a shed, especially in our sticky summers. The upfront cost stings a bit, but not as much as redoing a whole section because the underlayment gave out.
One thing I’ve noticed—if you’re managing multiple properties, the peace of mind is worth it. Less babysitting crews, fewer emergency calls. Still, I get why some folks go with felt if they’re pinched for cash or it’s just a quick fix. Just gotta weigh the risk, like you said. No perfect answer, but I’d rather pay a little more than gamble on the weather roulette.