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

Cap nails were a game changer for me too - learned that lesson after a big gust sent half my underlayment flapping like a flag. I’ve noticed the “self-sealing” feature isn’t all it’s cracked up to be in colder weather. I’m in Michigan, so spring installs are always hit or miss. And yeah, some brands definitely wrinkle more than others once the sun comes out. The last roll I used got pretty wavy - almost looked like someone left a hair dryer on it all day. Not ideal when you’re trying to keep things smooth before shingles go down.

Can’t say I’ve had much luck with the self-sealing stuff either - last fall, I did my shed roof and figured it’d be fine. Nope. The corners peeled up after a week of cold nights. What worked for me was using cap nails every 12 inches, then going back when it warmed up and pressing down the seams by hand. Not perfect, but at least it stayed put until shingles went on. I’d avoid installing in early spring if you can help it... Michigan weather just doesn’t cooperate.

Not gonna lie, I’ve had a love-hate relationship with self-sealing underlayment too, but I think it gets a bit of a bad rap in cold climates. Michigan’s spring is basically a coin toss - either you’re sweating or scraping frost off your windshield. Still, I’ve managed to get the self-sealing stuff to behave, even on a couple of windy lakefront jobs.

Here’s the trick that’s worked for me (and yeah, it sounds like overkill): roll out the underlayment and let it “relax” for an hour or two if the sun’s out at all. It softens up just enough so those corners don’t curl like potato chips. Then, hit the seams with a heat gun - not enough to melt anything, just enough to warm up the adhesive. It’s a pain, but it beats chasing loose corners in 30 mph gusts.

Cap nails every foot definitely helps, but I’ve found if you’re using a synthetic underlayment (the plastic-y stuff), you can sometimes get away with fewer fasteners if you time it right. The real kicker is making sure you overlap everything by at least 6 inches - most folks skimp here and then wonder why water sneaks in sideways.

One thing I’d push back on: waiting for perfect weather in Michigan is like waiting for a polite seagull. Sometimes you just gotta work with what you’ve got. If you’re stuck doing it early spring, maybe try tarping overnight or stacking some old shingles along the edges until things warm up. Not pretty, but neither is explaining water stains to your spouse.

If you’re still fighting with peeling corners, check the brand too - some of those bargain rolls are about as sticky as a Post-it note in January. The pricier stuff actually seems to grip better when it’s cold, at least in my experience.

Anyway, nothing’s foolproof around here - except maybe duct tape, and even that has its limits after a blizzard...

I hear you on the Michigan weather roulette - one day it’s 70 and sunny, next day you’re shoveling snow off the roof. I’ve been burned by self-sealing underlayment in April more than once. The “relax in the sun” trick is something I wish I’d learned sooner. My first go-round, I laid it out straight from the garage, corners curled up like crazy and I was chasing them around with a staple gun while the wind tried to carry half the roll to Canada.

I’ll second your point about overlap. People (including me, once) get stingy with that and then wonder why there’s water sneaking into the attic. Six inches minimum, sometimes more if I’m feeling paranoid or if it’s one of those weird sideways rain days.

As for brands, I used to cheap out and grab whatever was on sale at Menards, but honestly, that stuff barely stuck when it was cold. Switched to a pricier roll last time - can’t remember the name offhand - and it actually stayed put even when we had frost overnight. Sometimes paying a bit more upfront saves you a headache (and money) down the road.

I do think cap nails are worth every penny, though. Tried skimping on fasteners once and ended up with a section flapping in the wind by morning... lesson learned. Haven’t tried the heat gun trick yet - might give that a shot next time since my hands are usually frozen by noon anyway.

One thing I’ll push back on: synthetic underlayment is great for durability and weight, but I’ve found it can be slippery as heck when there’s dew or frost. Nearly took a tumble last spring, so now I always wear those grippy shoes if I’m up there early.

Anyway, nothing’s perfect in this climate but figuring out what shortcuts aren’t worth it has saved me more than once. And yeah... duct tape only gets you so far before Mother Nature laughs in your face.

Can definitely relate to a lot of this - Michigan weather just doesn’t play fair. I used to be all about saving a few bucks on underlayment, but after dealing with leaks and having to redo sections, I’m with you: the extra cost for higher quality is worth it. Last fall, I tried out a mid-range synthetic (I think it was Grace Tri-Flex or something similar) and it held up even through those early snows. But yeah, it’s slick as ice in the mornings... nearly lost my footing more than once. Grippy shoes are non-negotiable now.

I’ve also learned not to cut corners on overlap or fasteners. Tried using fewer cap nails once and ended up with the wind getting under there - had to climb up and fix it in freezing rain, which I wouldn’t recommend. One thing I do differently is I always check the forecast before starting; if there’s any chance of a cold snap or rain, I wait. It’s not always possible, but rushing has cost me more than waiting ever did.

It’s tempting to go cheap on materials, but factoring in time and hassle, the pricier stuff usually wins out for me.

I hear you on the Michigan weather - there’s just no predicting what you’ll get, and it’s brutal on materials. I’ve seen a lot of folks try to save a few bucks on underlayment, only to end up spending double fixing leaks or wind damage. That said, I’m still a bit skeptical about some of these mid-range synthetics. Grace Tri-Flex is decent, but I’ve had mixed results depending on the batch. Sometimes it holds up great, other times it seems to wrinkle or buckle if there’s any moisture trapped underneath before install. Maybe that’s just me being picky, but I’ve started leaning toward the higher-end synthetics or even self-adhered membranes for certain jobs.

The slickness is no joke either. I’ve had crew members nearly go off the edge more than once when frost hits those synthetics. We switched to shoes with aggressive tread and started laying down temporary walk boards if we’re working early mornings or after a cold snap. It slows things down, but it beats a trip to the ER.

About fasteners - totally agree. Cap nails are non-negotiable for me now, especially with these wind gusts we get off the lakes. I tried staples once (against my better judgment) and spent half a Saturday chasing flapping underlayment in 30-degree rain... never again.

Curious if you’ve noticed any difference in how these synthetics perform under metal versus asphalt shingles? I’ve run into issues with condensation under metal roofs when using some of the thinner synthetics, especially on low-slope sections. Wondering if anyone else has had to add an extra vapor barrier or switch up their approach for metal installs.

And yeah, waiting out bad weather is tough when you’re trying to keep a schedule, but every time I’ve rushed it’s come back to bite me. Still, sometimes you just have to roll the dice if there’s a tight window between storms.

Anyone else seeing big differences in longevity between brands? Or is it mostly about install technique and weather timing?

Curious if you’ve noticed any difference in how these synthetics perform under metal versus asphalt shingles? I’ve run into issues with condensation under metal roofs when using some of the thinner synthetics, especially on low-slope sections.

Yeah, I’ve seen that too. Metal over thin synthetic on a low pitch is just asking for trouble in our climate. I started using a heavier self-adhered membrane under metal, especially on barns and garages, and it’s made a difference with condensation. Still, nothing’s perfect - if the attic’s not vented right, you’ll get drips no matter what. As for longevity, I think install matters more than brand, but some of the cheaper synthetics just don’t hold up to UV if you get delayed by weather. Learned that the hard way last fall...

- Had similar issues with condensation under metal, especially on my shed (low slope, Midwest winters).
- Tried a budget synthetic first - regretted it. UV exposure during install made it brittle fast.
- Switched to a mid-grade peel-and-stick for the house roof (asphalt shingles, 6/12 pitch). No condensation problems there, but I think the attic venting helps more than the underlayment itself.

if the attic’s not vented right, you’ll get drips no matter what

- For metal roofs, I’d say thicker underlayment is worth the extra cost up front - less worry about leaks or tearing if you’re DIY-ing.
- If you’re on a budget like me, just don’t skimp on venting or you’ll end up paying for repairs anyway.
- Haven’t found a “perfect” product yet. Install quality and weather delays seem to matter more than brand in my experience.

If anyone’s curious about costs: my last roll of mid-grade synthetic was about $90 at Menards - held up fine for two weeks before shingles went on.

if the attic’s not vented right, you’ll get drips no matter what

Couldn’t agree more - seen way too many “mystery leaks” that turned out to be sweat, not rain. Folks love to blame the underlayment, but bad venting is the real villain half the time. I’ve crawled through enough attics to know... sometimes it’s like a sauna up there.

I’m with you on thicker underlayment for metal roofs. Tried to save a buck once with the thin stuff - regretted it when a stray boot heel punched right through. And yeah, install quality beats brand every day. I’ve seen top-dollar rolls mangled by a rushed crew.

You nailed it - venting gets ignored way too much. I used to think underlayment was the magic fix for everything, but after sweating buckets in a few attics, I get why folks say “it’s not the roof, it’s the air.” Had a job last summer where the homeowner swore their new underlayment was junk, but turns out, they had one sad little vent for the whole attic. No wonder it was raining indoors every morning.

I learned the hard way about thin underlayment too. One misstep and suddenly you’re patching holes instead of laying shingles. Never fun. The install crew makes or breaks it, for sure. I’ve seen the fancy stuff go to waste when guys rush or just don’t care. Doesn’t matter how expensive your roll is if it’s flapping in the wind by lunch.

Honestly, I’m all for spending a bit more on thicker underlayment and making sure the venting’s sorted first. Saves a lot of headaches (and sweaty afternoons) down the line.

Venting really is the unsung hero. I’ve lost count of how many times I’ve inspected “leaky” roofs where the real culprit was condensation from poor airflow, not the underlayment or shingles. People get fixated on the latest synthetic rolls or peel-and-stick, but if the attic’s basically a sauna, you’re just asking for trouble. I’ve seen brand new underlayment bubble and wrinkle within a year because moisture had nowhere to go.

I’m with you on thicker underlayment, though I’ll say I’ve seen some thinner synthetics hold up surprisingly well - if they’re installed right and the roof deck is solid. But yeah, one careless step and you’re patching holes, especially on steeper pitches. Crew quality is a huge variable. I’ve seen high-end materials wasted by rushed installs, and basic felt last ages when someone actually cares.

If I had to pick, I’d rather see a homeowner spend a bit less on fancy underlayment and put that money into proper ridge and soffit vents. It’s not glamorous, but it’s what keeps the whole system working.

If the attic’s basically a sauna, you’re just asking for trouble.

This hits home. When we bought our place last year, I was convinced the roof was leaking because there were water stains in the upstairs closet. Turns out, the attic vents were basically clogged with insulation and dust - no airflow at all. The inspector said the same thing: “You could put gold-plated underlayment up there and it’d still bubble if you don’t vent.”

We ended up spending more on adding ridge vents and clearing out the soffits than we did on the actual underlayment. Not glamorous, but since then, no new stains and the attic doesn’t feel like a steam room anymore. I do wonder sometimes if we should’ve gone with a thicker underlayment (we used a mid-grade synthetic), but honestly, it seems to be holding up fine.

One thing I’ll say - install quality is everything. Our neighbor had a fancy peel-and-stick but their crew left gaps around the chimney flashing, and now they’re fighting leaks every time it rains hard. Sometimes it’s less about what you buy and more about who installs it...

Sometimes it’s less about what you buy and more about who installs it...

That’s fair, but I gotta say, I’m still not convinced the materials don’t matter just as much. We went with a budget felt underlayment on our last house (installer was solid), and it still started curling after a few years. Maybe that’s just our crazy humid summers, but I’m leaning toward spending a bit more next time, even if the crew’s good.

We went with a budget felt underlayment on our last house (installer was solid), and it still started curling after a few years.

Funny, I had the opposite - premium synthetic stuff, but the installer clearly skipped a few steps. Ended up with leaks in three units. Ever try peel-and-stick? Wondering if that’s overkill or worth it in muggy climates like ours...

Peel-and-stick is actually what I’ve started recommending for our properties, especially after a few too many headaches with both felt and synthetic. We’re in a humid area too, and the storms here are no joke. I used to think peel-and-stick was overkill, but after seeing how it holds up - especially around tricky spots like valleys and skylights - I’m convinced it’s worth the extra upfront cost.

One building we manage had constant issues with leaks around the vents, even with “high-end” synthetic underlayment. Switched to peel-and-stick on the next roof job, and it’s been bone dry through two hurricane seasons. The install takes a bit longer, and yeah, it’s pricier, but honestly, not having to deal with emergency calls during every big rainstorm is a game-changer.

I do think the installer matters just as much as the material, though. Even the best stuff can fail if someone cuts corners. But if you’re in a muggy climate and want peace of mind, peel-and-stick is hard to beat... at least in my experience.

I hear you on the peace of mind. I switched to peel-and-stick after a nasty storm last year took out half my old roof (had felt underlayment at the time). The extra cost stung a bit, but I haven’t had a single leak since, even with some wild wind and rain this spring. I do notice it gets a bit trickier around the chimney - my installer had to go back and reseal a couple spots where it didn’t quite lay flat at first.

Curious if you or anyone else has noticed any issues with the heat making it bubble or peel over time? Summers here get brutal, and I’ve heard mixed things about long-term adhesion, especially on south-facing slopes. Also, did you go full peel-and-stick everywhere, or just in the problem areas like valleys and around penetrations? I ended up doing the whole thing for peace of mind, but sometimes wonder if I went overboard...

I went full peel-and-stick too after a couple bad leaks, and yeah, the price tag made me wince. Haven’t had bubbling, but I did notice some edges lifting a bit on the south side last August - nothing major, just had to press them back down. My installer said it’s pretty normal with our heat swings. Around the chimney was a pain, though... took a few tries to get it sealed right. I sometimes wonder if just doing the valleys and penetrations would’ve been enough, but honestly, sleeping through a thunderstorm without worrying is worth it for me.

That edge lifting you mentioned is something I see a lot, especially on the south or west sides where the sun just bakes everything. Pressing it back down usually does the trick unless it starts to curl or get debris under there. Heat swings are rough on peel-and-stick, but honestly, most of the time it’s still way better than old-school felt in terms of holding up to leaks.

I get what you mean about the chimney being a pain. Flashing and sealing around chimneys seems to be where a lot of leaks start, no matter what underlayment you use. I’ve seen some folks try to just double up in those areas - like, peel-and-stick just in valleys and around penetrations, then regular synthetic everywhere else - to save money. Sometimes it works out, sometimes not so much if water finds its way in somewhere unexpected.

Curious if you noticed any difference in attic temps after switching? I’ve had a few homeowners say their attics felt warmer with peel-and-stick, maybe because it seals things up tighter and doesn’t breathe like felt did. Not sure if that’s a real thing or just perception, but I’m always interested if folks see changes in ventilation or moisture after swapping underlayments.

And yeah, peace of mind during storms is huge. I’d take a little edge lifting over waking up to water stains on the ceiling any day... Still, I wonder if anyone’s tried those newer “breathable” self-adhesive membranes? Supposedly they let moisture out but keep water from getting in. Haven’t seen enough installs yet to know if they’re worth the extra cost or just marketing.

What kind of shingles did you go with over the peel-and-stick? Some brands seem to play nicer with it than others, at least from what I’ve seen on tear-offs.

Edge lifting drives me nuts, especially when you get those hot afternoons and the stuff just won’t stay put. I’ve had better luck with CertainTeed shingles over peel-and-stick than GAF, honestly - seems like the adhesive on some brands just reacts weirdly, almost like it softens up and lets the shingle slide a bit. The attic temp thing is real in my experience, but I wonder if it’s more about ventilation setups than the underlayment itself. Anyone ever see condensation issues crop up after swapping to peel-and-stick? That’s the one thing that makes me hesitant to use it everywhere, especially on older houses.

Anyone ever see condensation issues crop up after swapping to peel-and-stick?

That’s a solid question. I’ve seen a few older homes where condensation popped up after switching, but it’s tough to say if it was just the underlayment or a combo of poor attic airflow and insulation gaps. Did you notice any musty smells or staining after the swap? Sometimes it’s subtle at first. Ventilation really seems to make or break it, especially in humid spots.