If underlayments could talk: which one would outlast the others?

Gotta say, synthetic underlayment would probably have the wildest “bar stories” if they could talk - especially after seeing what some of the newer synthetics can handle. I’ve pulled up old felt that looked like it’d been through the wringer after a few years, especially in humid climates down south. Always seemed to hold on just enough to get the job done, but man, it was rough around the edges after a big storm.

Now, I’ve seen synthetics sit exposed for weeks during delays and still look basically untouched. The UV resistance is no joke. One job, we had a rain delay for nearly a month and the synthetic didn’t even curl. Felt would’ve been toast. Rubberized is a beast for waterproofing, but it’s overkill unless you’re in a spot that gets ice dams or you need extra protection around valleys and eaves.

If you want a simple breakdown: felt’s the scrappy old-timer, synthetic’s the one that laughs at the sun, and rubberized is the strong silent type who only steps in when things get dicey. All have their place, but for sheer “life story”? My money’s on synthetic these days.

Gotta say, synthetic underlayment would probably have the wildest “bar stories” if they could talk - especially after seeing what some of the newer synthetics can handle. I’ve pulled up old f...

Had to laugh at the “synthetic’s the one that laughs at the sun” bit - feels spot on. I manage a few properties in the Midwest, and after a couple of brutal windstorms, I’ve seen firsthand how each type holds up. Here’s what happened last spring: we had a project delayed for almost three weeks due to nonstop rain. The crew had already laid down synthetic underlayment, and honestly, I was worried it’d be trashed by the time shingles went on. But when I checked, it looked pretty much the same as day one. No curling, no weird bubbling, just... fine.

Contrast that with an older building we still have with felt underlayment. After a hailstorm, I peeked under some loose shingles and the felt was basically falling apart - cracked, soft, and just sad looking. I get why people still use felt (cost mostly), but for me, synthetic is worth the extra upfront.

Rubberized is great in theory, but unless you’re dealing with ice damming or really tricky roof shapes, it just feels like overkill. Maybe I’m old school, but I still think felt has its place for quick fixes or budget jobs. For anything long-term though? Synthetic’s earned its keep.

I get why people still use felt (cost mostly), but for me, synthetic is worth the extra upfront.

That’s been my experience too. I used to be all about the old-school felt because it’s what everyone around here used, but after a few rough winters, I got tired of patching spots where it just gave up. The last time we had a reroof delayed by weather, the synthetic underlayment sat exposed way longer than I’d like to admit, and it still looked solid - no rips or weird spots.

The only time I’ve found rubberized really made sense was on a low-slope porch roof where ice damming is a constant headache. Otherwise, it does feel like overkill for most of my jobs.

I’ll still grab felt if I’m in a pinch or doing something temporary, but for the long haul? Synthetic wins out. It’s one less thing to worry about when storms roll through and you can’t get shingles on right away.

I’ve seen synthetic hold up way better during construction delays, too. In our area (lots of sudden storms), it’s a relief not having to worry about leaks if shingles get pushed back. Felt’s fine for quick jobs, but synthetic’s saved me a few headaches.

I get what you’re saying about synthetic - it’s definitely bailed me out when weather threw a wrench in the schedule. We had a job last spring where rain came out of nowhere and the shingles were delayed a whole week. The synthetic underlayment didn’t even budge, no leaks, no bubbling, nothing. If that had been felt, I’m pretty sure we’d have been dealing with water stains or worse.

That said, I’ve heard some old-timers say felt “breathes” better and can handle a bit of moisture without trapping it underneath. Not sure I buy it, but maybe there’s something to it for certain roofs or climates? Around here (midwest), the wind just shreds felt if you leave it exposed too long. Anyone ever tried one of those hybrid underlayments - like the self-adhered ones? Wondering if they’re worth the extra cost or just overkill unless you’re doing metal or low-slope roofs...

Had a crew use the self-adhered stuff on a flat section over my office last year - pricey, but it was like sticking down a giant roll of duct tape. Zero leaks, even after a week of storms. Only downside: if you mess up the placement, good luck peeling it back up. Has anyone run into issues with it in hot weather? I’m always worried about things turning gooey when the sun’s baking.

Only downside: if you mess up the placement, good luck peeling it back up.

That’s exactly what I was worried about when I looked at self-adhered for my shed roof - felt like a one-shot deal, and I’m not the most precise DIYer. Price tag put me off, too. As for hot weather, I live in Texas and had neighbors say the stuff gets tackier but hasn’t melted or oozed (yet). Still, I always wonder if it’ll start creeping down the walls by August...

Yeah, that “one shot” thing with self-adhered underlayment makes me nervous too. I’ve heard stories about folks getting it stuck crooked and then basically having to cut it off and start over. The heat here (I’m in Oklahoma) definitely makes it stickier, but I haven’t seen any actual melting or dripping either - just gets a bit soft on the hottest days. Have you looked into synthetic underlayments? They’re lighter and seem a little more forgiving if you need to reposition, though maybe not as bulletproof as the peel-and-stick stuff.

I get the appeal of synthetics - they’re definitely lighter and easier to handle, especially if you’re working solo or in the heat. But I’ve actually had better luck with the peel-and-stick, even with the “one shot” risk. On a couple of our properties, the self-adhered stuff held up way better during those crazy spring storms we get here. The trick for us was to have two people on the install and take it slow. It’s a pain if you mess up, but the peace of mind during tornado season is worth it for me. Synthetic’s great for quick jobs, but I’m not convinced it’ll outlast the heavy-duty peel-and-stick in our climate.

I hear you on the peel-and-stick holding up better in wild weather. I’m in central Oklahoma, so tornado season is always on my mind too. We tried synthetic on our garage roof last year - mainly because I didn’t want to wrangle those heavy rolls by myself in the heat. It went on fast, but I noticed after a couple of months, some edges started to curl up a bit where the wind hits hardest. Didn’t fail completely, but it made me nervous enough that I went back and tacked those spots down.

Peel-and-stick felt more “set it and forget it” for our main house, but man, that stuff is unforgiving if you get it crooked. My wife jokes it’s like putting on a giant sticker with no do-overs. Still, once it’s down, I sleep better during those crazy spring storms.

I’m curious - has anyone had issues with the peel-and-stick getting brittle over time? My neighbor said his started cracking after about 10 years, but his attic gets way hotter than ours. Maybe it’s a ventilation thing? Or maybe the brand matters more than I thought.

Also, for folks in colder climates, does the self-adhered stuff ever have trouble sticking if you’re installing in cooler temps? We only ever did it in late spring, so I never had to deal with that, but I’ve heard stories about the adhesive not grabbing right if it’s chilly.

For what it’s worth, I’d probably still pick peel-and-stick for anything that really matters, especially with our weather. But I get why folks go synthetic for sheds or quick flips. Just wish there was a version that was as easy as synthetic but as tough as peel-and-stick... maybe someday.

- Gotta say, I’m not totally sold on peel-and-stick for every situation.
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“Peel-and-stick felt more ‘set it and forget it’ for our main house, but man, that stuff is unforgiving if you get it crooked.”

“Peel-and-stick felt more ‘set it and forget it’ for our main house, but man, that stuff is unforgiving if you get it crooked.”

That’s exactly my struggle - one misstep and you’re fighting bubbles or wrinkles forever. I’ve noticed synthetic holds up better for us in humid summers, but the curling drives me nuts. Anyone else find that peel-and-stick just doesn’t play nice with older, uneven decking?

Peel-and-stick on old decking is a nightmare, honestly. I tried it on my porch roof last fall - thought it’d be a quick win, but the uneven boards made it almost impossible to get a smooth lay. Ended up with a few bubbles that just wouldn’t flatten out, no matter how much I pressed. I do like how tough the synthetic stuff is in our muggy summers, but yeah, the curling at the edges is a pain. Wonder if anyone’s had luck with a primer or something to help it grip better on rough wood?

- Tried peel-and-stick over my old deck boards last spring - same deal with bubbles and edges lifting.
- Thought about using a primer, but the price kinda put me off. Not sure if it’d actually help or just add another step/cost.
- For me, the rougher the wood, the worse it stuck. Even swept and washed before, still got spots peeling up after a hot week.
- Wondering if anyone’s had better luck with a cheap roll-on adhesive? I’m not convinced the fancy stuff is worth it on old wood...
- Honestly, might just go with regular felt next time. Less hassle, even if it doesn’t last as long.

Wondering if anyone’s had better luck with a cheap roll-on adhesive? I’m not convinced the fancy stuff is worth it on old wood...

Tried roll-on adhesive last year - honestly, it was less messy than I expected, but didn’t solve the peeling on my rough deck boards either. Maybe it helps on smoother surfaces, but my boards are like sandpaper. Felt’s not fancy, but at least it doesn’t pretend to stick where it won’t.

I’ve seen the same thing - those roll-on adhesives just don’t grab onto rough, splintery boards. I inspected a place last fall where the owner tried it over old pine planks, and it peeled up in sheets after the first freeze. Sometimes old-school felt is just more honest about its limits.

I get where you’re coming from - old felt’s definitely got its place, and yeah, it’s honest about what it can and can’t do. But I’ve seen a lot of folks write off the newer synthetics or adhesives too quick just because they had a bad install or the wrong surface. That roll-on stuff isn’t magic, but it’s not all junk either. The real problem is slapping it down on rough, splintery boards like you mentioned. If the deck’s not prepped right, nothing’s gonna stick well, not even the best felt.

I was on a job last spring where we had to re-deck half the roof because the old boards were so warped and splintered. The homeowner wanted to save money and just put synthetic underlayment over it, but we talked him into at least replacing the worst spots. Once we did that, the synthetic stuck like glue - even through a nasty hailstorm a few months later. No leaks, no peeling.

Honestly, I think a lot of these failures come down to skipping prep or trying to cut corners. Felt will forgive you a bit more if your deck’s rough, but then you’re trading off lifespan and weather resistance. Synthetics and adhesives need a smoother surface, but if you give them that, they’ll outlast felt by years in my experience.

Not saying felt’s useless - sometimes it’s all you can do on an old house with a tight budget. But if you want something that’ll really last (and you’re willing to put in the work up front), synthetics are worth another look. Just don’t expect miracles if you’re rolling them onto splinters and hoping for the best...

If the deck’s not prepped right, nothing’s gonna stick well, not even the best felt.

That part really rings true. I’ve managed a few older buildings over the years and I can’t count how many times someone tried to save a buck by skipping the prep. In my experience, it’s almost never worth it in the long run. One project that sticks out: we had a 1920s duplex with original plank sheathing - tons of gaps and splinters. The previous owner just slapped felt over it and called it good. Fast-forward two winters, and we were dealing with leaks around every vent.

When we finally got up there to redo things, here’s what actually made a difference:
1. Pulled up all the old felt and did a full inspection of the deck - marked every spot that was soft or had big gaps.
2. Replaced about 25% of the boards (more than I budgeted for, but worth it).
3. Sanded down some rough spots - not fun, but it made a huge difference for adhesion.
4. Went with a synthetic underlayment this time, since our weather’s all over the place (Midwest - one week it’s snowing, next it’s 90°F).
5. Made sure all fasteners were flush - no popped nails or screws poking up.

Result? No leaks for three years and counting, even after some wild storms last spring.

I do think felt has its place - like you said, sometimes you’ve got no choice on an old roof or if money’s tight. But if you’re aiming for longevity and less hassle down the road, prepping well and using synthetics just makes sense to me. It’s not about magic materials; it’s about doing each step right.

Funny enough, I’ve found that tenants never notice when you do things right... but they always notice when there’s a leak over their kitchen table! If underlayments could talk, they’d probably say “just give me a smooth spot to hang out and I’ll do my job.”

You nailed it with the prep making all the difference. I tried to shortcut sanding on my garage roof (figured the shingles would cover it anyway), and sure enough, the underlayment bubbled up in spots. Had to redo that section a year later. I’m curious - did you notice any difference in how the synthetic handled the temperature swings? Mine seemed to lay flatter than felt, but maybe that’s just me.