You nailed it with the “soggy burrito” bit—felt just doesn’t stand a chance if you get caught in a downpour mid-job. I’ve seen more than one crew scrambling to re-tack felt after a surprise storm. Synthetic’s definitely tougher for that, and it’s less likely to rip if wind kicks up before shingles are down. That said, I’ve patched up plenty of old roofs with 30-year-old felt still hanging on, so it’s not like felt’s useless. Like you said, install matters a ton. And ice & water shield at the valleys? Couldn’t agree more—it’s saved my bacon more than once after hail tore up the main field.
Had a job last summer where a freak thunderstorm rolled in before we could get shingles down. The synthetic held up—no tears, no leaks, just had to squeegee off the water. If that had been felt, we’d have been redoing half the roof. Still, I’ve seen some old felt that surprised me with how well it lasted, especially on low-slope roofs. Install and weather really do make all the difference.
That’s been my experience too—synthetic can take a pounding and just shrugs it off, especially when the weather turns nasty out of nowhere. But I do wonder if we sometimes underestimate old-school felt. I’ve seen 30-year-old felt under some ancient three-tabs that still looked decent, but only where it was installed right and didn’t get baked by the sun. Still, after seeing synthetic handle standing water without a hitch, I’d have a hard time going back unless it was a super low-slope or budget job. Installation and climate are everything, though... one bad staple or a little wind lift and even the best underlayment’s in trouble.
I’ve seen 30-year-old felt under some ancient three-tabs that still looked decent, but only where it was installed right and didn’t get baked by the sun. Still, after seeing synthetic handle st...
I get the appeal of synthetics, especially when you mention how they handle standing water, but I’m not totally convinced they’re always the slam dunk folks think they are. The thing about felt is, if you’ve got a steep enough pitch and good ventilation, it can last ages—like you said, “only where it was installed right and didn’t get baked by the sun.” I’ve pulled up felt that survived decades of Midwest freeze/thaw cycles and still had some life left. Synthetics start to break down under UV if left exposed too long before shingles go on, and I’ve seen some cheaper rolls tear way too easy if you’re not careful walking on them. Not saying felt’s perfect, but I wouldn’t count it out for every job. Sometimes the tried-and-true stuff just works.
That’s a fair point about synthetics not being a cure-all. I’ve noticed the same thing with UV exposure—if the shingles don’t go on quick, some of those synthetic sheets get brittle or even start curling at the edges. Felt definitely has its place, especially on steeper roofs where water just runs right off. I guess it really comes down to matching the underlayment to the job and climate. Sometimes the old-school stuff just holds up better than you’d expect.