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

You nailed it with the UV resistance. I’ve seen way too many jobs where felt just couldn’t keep up - especially if the crew gets delayed and the roof sits open for a bit. Last summer, I inspected a place where the felt had been exposed for maybe ten days, and it was already brittle and tearing at the nail heads. The synthetic stuff next door? Still tight as a drum, no curling or weird spots.

I hear you on the recycling claims. Around here, demo debris goes straight to the landfill, no matter what the packaging says. It’s frustrating, but I guess if the synthetic lasts longer and keeps the roof dry, that’s a trade-off most folks are willing to make. Would be nice if someone figured out a way to actually recycle this stuff, though. Until then, I’d rather see a roof last 30 years with less maintenance than have to patch leaks every few seasons.

Weight difference is no joke either. My knees aren’t what they used to be, and dragging felt up a steep pitch is just asking for trouble. Synthetic’s lighter, grippier, and honestly, just makes the job safer.

Weight difference is no joke either. My knees aren’t what they used to be, and dragging felt up a steep pitch is just asking for trouble. Synthetic’s lighter, grippier, and honestly, just makes the job safer.

That’s exactly what tipped the scales for me a couple years back. We had a rehab on a 1920s duplex with one of those crazy steep roofs. The crew was cursing the old felt every day - slippery, heavy, and it started tearing at the edges after just a few days of sun. I ended up switching mid-project to synthetic, and the difference was night and day. Guys moved faster, nobody slid off (which was my biggest worry), and no one complained about carrying rolls up the ladder.

I do wish there was a better solution for recycling, though. We’re in a city that talks big about sustainability but still dumps everything from demo jobs. I get why folks stick with synthetic despite that - less patching, fewer emergency calls after storms. But I can’t help thinking we’re just kicking the can down the road on the landfill problem.

Anyway, if you’re managing multiple properties like I am, the fewer leaks and repairs you have to juggle, the better. Synthetic’s been a solid trade-off so far... even if it’s not perfect.

- Had a similar situation after that big hailstorm last spring - old felt just shredded, and we were patching nonstop.
- Swapped to synthetic on the next job (asphalt shingles, 7/12 pitch, Midwest weather). Crew was skeptical at first but ended up liking it way more - especially hauling it up ladders.
- Noticed fewer blow-offs during storms since then. Used to get calls every time the wind hit 40mph... now, not so much.
- Only gripe: synthetic gets slick with frost or dew. Had a guy nearly take a slide at sunrise - so it’s not perfect, but still better than felt in most cases.
- Recycling is a pain, yeah. Haven’t found a good answer there either. Feels like we’re trading one problem for another sometimes.
- For storm repairs, though, I’ll take the trade-off. Less emergency tarping and fewer callbacks make my life easier, even if I’m still hunting for something more eco-friendly down the line...

I get why everyone’s moving to synthetic, but I’m still not totally sold for every job. On a low-slope or porch roof, I’ve noticed the slickness is a real hazard - especially if you’re working before the sun’s up. One time last fall, we had to lay down extra planks just to keep from sliding off. Also, with certain brands, the staples don’t always grab as well as they do with felt, which can be a pain if you’re in a rush and weather’s rolling in. Maybe it’s just what I’m used to, but sometimes old-school felt feels more forgiving when you’re patching small sections or doing quick repairs. Synthetic definitely wins on weight and durability, though... just wish there was a version that wasn’t so slippery when wet.

That slickness is no joke - nearly went sledding off a porch roof myself last spring, and I was just trying to get a tarp down. The lighter weight on those big rolls is nice, but when you’re on a pitch that’s just shy of flat, it feels like skating on ice. Have you tried any of the “grip” synthetics yet? Heard mixed things. Also, curious if you’ve found a staple pattern that works better with synthetic... seems like sometimes they just pop right back out as soon as there’s a little wind.

That “skating on ice” feeling is way too real. I’ve had a couple close calls myself, especially when the dew hits early and you’re still trying to get things tacked down before the sun’s up. Tried one of those grip synthetics last fall - can’t say it was a miracle, but it did feel a bit less like I was about to end up in the neighbor’s yard. Still, once there’s any dust or shingle grit, it’s back to being slick as ever.

Staples have been hit or miss for me too. Sometimes they hold fine, other times I’m chasing underlayment across the yard after a gust. I started doubling up at the seams and corners, but honestly, cap nails seem to work better if you can swing it. The only downside is they take longer and my boss grumbles about “wasting time.” Haven’t found a perfect pattern yet - seems like every brand acts a little different.

I do like how light the rolls are compared to felt, but I’m not convinced any of them are truly “grippy” enough for steep pitches. Maybe someone else has cracked the code, but for now I’m just moving slow and hoping for dry boots...

I started doubling up at the seams and corners, but honestly, cap nails seem to work better if you can swing it. The only downside is they take longer and my boss grumbles about “wasting time.”

That’s been my struggle too. Cap nails just seem to hold better, especially when the wind picks up, but yeah - the extra time adds up. I’ve tried a few “grip” synthetics and honestly, none of them feel totally safe on a steep roof once there’s grit or morning dew. One trick that’s helped me a bit is sweeping off the dust as I go, but that’s not always practical when you’re racing weather. At the end of the day, I’d rather move slow and stay upright than risk a tumble... no underlayment is worth a trip to the ER.

At the end of the day, I’d rather move slow and stay upright than risk a tumble... no underlayment is worth a trip to the ER.

Couldn’t agree more. I’ve seen too many guys try to rush with those “fast install” synthetics, only to end up sliding halfway down a 10/12 pitch. Cap nails are a pain, but after patching up wind damage on jobs where folks cut corners, I’m not convinced any shortcut is worth it. Bosses grumble, but they’re not the ones footing the hospital bill or warranty call.

Cap nails are the bane of my existence, but I’d rather deal with sore thumbs than a busted hip. Had a guy try to “save time” with peel-and-stick last summer - he spent more time sliding around than actually working. Slow and steady wins, especially on a steep roof.

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“he spent more time sliding around than actually working”

Totally get what you mean about sliding around - had a guy nearly end up in the neighbor’s yard trying to lay peel-and-stick on a 10/12 in July. I’ll take synthetic any day, especially after seeing how felt just turns into mush after a couple storms. Cap nails are annoying, but man, at least you know it’s not going anywhere when the wind picks up.

Had a similar situation last summer - steep pitch, mid-July, and the felt just wouldn’t stay put. Guys were slipping all over the place, and by the time we finished, half of it was already wrinkling up. Switched to synthetic after that and haven’t looked back. Yeah, cap nails slow things down a bit, but I’ll take that over having to redo the whole underlayment after a windy night. Felt just doesn’t hold up in this climate, not worth the hassle.

I get where you’re coming from with felt, but I’ve actually had better luck with it than synthetic in a few cases. On my garage roof (pretty steep, northeast), the heavier 30 lb felt held up fine for a week before shingles - no wrinkles or blow-offs. Maybe it’s just luck, or maybe the way it was installed, but I still think felt can work if you’re careful and the weather cooperates. Synthetic’s easier to handle, sure, but it can be slippery as ice on a steep pitch... not a fan of that.

Synthetic’s easier to handle, sure, but it can be slippery as ice on a steep pitch... not a fan of that.

That’s my main gripe with synthetic too - on anything over a 6/12 pitch, it feels like you’re working on a skating rink. I’ve seen more than one guy take a slide. As for 30 lb felt, I’ll admit it’s held up for me in stretches, but I’ve also had it wrinkle up in humid weather or after a hard rain. Did you use cap nails or just staples? Sometimes the fastener choice makes all the difference. Weather’s such a wildcard though...

Synthetic’s definitely slick, but I’ve got to push back a bit on the felt side. Seen just as many issues with felt as with synthetic, especially after a storm rolls through.

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As for 30 lb felt, I’ll admit it’s held up for me in stretches, but I’ve also had it wrinkle up in humid weather or after a hard rain.

- Synthetic’s slippery, no doubt, but I’ve found the newer textured stuff (like Sharkskin or Titanium) gives a bit more grip. Not perfect, but better than the old blue tarps they used to call underlayment.
- On steep pitches, I just use roof jacks and harnesses. Not ideal, but I’d rather deal with that than have to redo felt after every rain.

- Cost-wise, synthetic’s a little more upfront, but I’ve saved on labor and repairs. Haven’t had to replace a single sheet mid-job since switching.

- One thing nobody talks about: synthetic doesn’t soak up water, so if you get caught in a storm mid-roof, it dries out fast. Felt turns into mush.

Not saying synthetic’s perfect, but for storm-prone areas, I’ll take slippery over soggy any day. Just my two cents.

Can’t argue with you on the humidity - down here in Florida, felt just doesn’t stand a chance. First time I helped lay it, we had a pop-up shower and the stuff looked like a crumpled paper bag by the next morning. Tried cap nails and even doubled up the edges, but the wind still found a way to get under there.

I’ll admit, synthetic’s not my favorite to walk on, especially on a 10/12 pitch... but I’d rather take it slow with a harness than have to chase felt halfway down the street after a storm. The textured ones are definitely less sketchy, but I still move like a grandma up there.

Price was a shock at first, but after having to redo a section of felt twice in one week (thanks, summer storms), I get why folks say synthetic pays for itself. Only thing I miss about felt is how easy it is to cut - synthetic can be stubborn if your knife’s dull.

All in all, I’m with you: soggy underlayment is just asking for trouble. If it’s gonna rain sideways every other afternoon, might as well go with what holds up.

- Had a similar experience last hurricane season - felt just turned to mush after two days of rain, even with extra fasteners.
- Switched to a recycled synthetic (trying to keep it green where I can). Not the easiest to cut, but it held tight through some nasty wind gusts.
- Agree on the price - stings at first, but not having to redo sections is worth it.
- Only real gripe: gets slick when there’s morning dew, so I’m extra careful on steeper slopes.
- Still, I’d rather deal with that than peeling up soggy felt every time the weather turns.

- Seen the same thing with felt - once it’s soaked, it’s basically useless, especially in humid climates.
- Synthetics are a big step up for wind and water resistance. I’ve noticed they don’t wrinkle or tear as easily when installers walk on them, which helps with shingle alignment later.
- Price is higher, but if you factor in labor for repairs, it balances out over time.
- The slickness is real - almost wiped out on a 7/12 pitch last fall. Some brands have a bit more grip, but none are perfect.
- Only downside I’ve run into: some synthetics can trap moisture if the decking isn’t vented well. Worth double-checking attic airflow before switching over.

Can definitely relate to the felt issues - down here in the Gulf, once it’s wet, it’s game over. I’ve switched almost entirely to synthetics for re-roofs, mostly because of the durability and how they handle foot traffic. You’re spot on about the wrinkle factor. With felt, I’d see it bunch up under shingles, especially if we had a rain delay, and then you’re fighting alignment the whole way up.

The slickness is no joke, though. Had a guy on my crew take a pretty good slide last summer - luckily, he was roped in, but it rattled him. I’ve noticed some brands (like Deck-Armor) seem to have a bit more grip, but it’s still not something I’d trust on a steep pitch without fall protection. Curious if anyone’s found a synthetic that’s noticeably less slippery? I’ve tried a few, but haven’t found one that really solves it.

On the moisture side, I’ve run into that with older homes where attic venting isn’t up to code. Synthetics just don’t breathe like felt, so if there’s any kind of condensation issue, it’ll show up quick. Had a job last year where the decking started to cup because moisture got trapped - ended up having to add more soffit vents and a ridge vent after the fact. Not ideal, but lesson learned.

Has anyone tried those “breathable” synthetic underlayments? I’ve seen them advertised but haven’t heard much from folks actually using them in the field. Wondering if they’re worth the extra cost or just marketing hype.

I’ve been wondering about those “breathable” synthetics too. I’m in an older house with a low-slope roof, and after a bad rain last year, we had some moisture show up in the attic - nothing major, but enough to make me nervous. I keep hearing that the new synthetics are supposed to be better, but I can’t tell if it’s just clever marketing or if they actually help with trapped moisture. Has anyone noticed a real difference in how their attic feels or smells after switching? I’m trying to figure out if it’s worth paying extra or if I should just stick with what’s worked so far...