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

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.

Totally get where you’re coming from. I was skeptical too, but after switching to a “breathable” synthetic last year, I did notice less of that musty attic smell after heavy rain. Here’s what I did: first, checked my vents to make sure airflow was decent (sometimes it’s not just the underlayment). Then, after the new stuff went on, I kept an eye - and nose - out for any changes. It wasn’t a night-and-day difference, but I felt like things dried out faster. If your old setup’s working, maybe try improving ventilation first before spending extra. But if you’re already re-roofing, I’d say the upgrade is worth considering.

It wasn’t a night-and-day difference, but I felt like things dried out faster.

I’ve seen the same thing on a few jobs - sometimes the “miracle” claims are a stretch, but there’s real improvement if you’re dealing with heavy humidity or big temperature swings. Had one client with stubborn mildew in the attic, and after swapping to a synthetic with better permeability, the musty smell faded over a few months. That said, I’ve also seen folks spend a fortune on underlayment when their soffit vents were clogged with insulation… sometimes it’s the little stuff that makes the biggest difference.

- Totally agree about the little stuff making a big difference.
- I’ve been tempted by the pricier underlayments, but honestly, fixing my attic venting and sealing up a few gaps did more than any fancy product.
- For me, the synthetic stuff helped in spots where we always had dampness, but it wasn’t magic - just part of the puzzle.
- Kind of wild how clogged soffits or a missing baffle can mess things up way more than most folks realize.
- If you’re watching costs, I’d say check airflow and insulation first before dropping cash on upgrades... learned that the hard way.

I went down the rabbit hole of underlayment brands a couple years back, but honestly, sealing up the attic hatch and adding some baffles in the soffits made a bigger difference than any upgrade I tried. If you’re on a budget, my order was: check for airflow issues, then insulation gaps, then underlayment. The fancy stuff is nice but not a cure-all - learned that after chasing leaks for a whole winter.

I hear you on the attic hatch - mine was basically a wind tunnel until I finally sealed it up. Did you notice any difference in your heating bill after adding baffles and sealing things up? I keep wondering if that stuff pays for itself over time, or if it just makes the house feel less drafty.

I had a similar situation with my attic hatch - before I sealed it, you could actually feel cold air pouring down in the winter. I added baffles, sealed up every gap I could find, and put in some extra insulation. The first winter after doing all that, my heating bill dropped by maybe 10-15%. Not a massive difference, but enough to notice, especially since my house is older and not the tightest to begin with.

Honestly, the biggest change was just how much more comfortable the upstairs felt. No more weird drafts or cold spots around the hatch. I do think the payback depends a lot on your climate and how bad the leaks were to start with. For me, it wasn’t a miracle fix for the bills, but it definitely made the house feel less drafty and more consistent temperature-wise.

Curious if anyone’s seen bigger savings from sealing up the attic? Sometimes I wonder if I missed something or if my old windows are just undoing all my hard work...

Curious if anyone’s seen bigger savings from sealing up the attic? Sometimes I wonder if I missed something or if my old windows are just undoing all my hard work...

Honestly, you nailed the main issues already - attic hatches are notorious for leaks. But yeah, old windows can absolutely kill your progress. I’ve seen clients dump money into insulation and still lose heat through 1970s single-pane glass. Sometimes the drafty feeling is more about air leaks than just insulation value. If your underlayment’s holding up but you’re still not seeing big savings, check around those windows and maybe even your rim joists in the basement. That’s where a lot of sneaky leaks hide, especially in older homes.

I’ve been down this road myself, patching up the attic and thinking I’d see a huge drop in my energy bill. Didn’t quite work out that way. What actually made the biggest difference for me was when I finally dealt with the original wood windows - beautiful, but drafty as heck. Even after weatherstripping, there was still cold air sneaking in around the frames.

I also found that the rim joists in my basement were letting in more air than I realized. A couple cans of spray foam and some rigid foam board made a noticeable improvement, honestly more than adding another layer of insulation up top.

It’s easy to get tunnel vision with attic work, but in my experience, it’s usually a combination of small leaks all over the house that add up. If your underlayment’s holding up, maybe give those windows and basement edges another look. Sometimes it’s not the big-ticket stuff, just a lot of little gaps working against you.

That’s interesting, because my experience was almost the opposite. We spent ages fussing with our old windows and basement cracks, but the real game-changer was finally getting the attic properly sealed and insulated. Maybe it’s just our house (built in the ‘50s, low-pitch roof), but the temperature swings were wild until we tackled the attic. I guess every house has its own quirks - sometimes it’s the little stuff, sometimes it’s just one big weak spot.

I guess every house has its own quirks - sometimes it’s the little stuff, sometimes it’s just one big weak spot.

That’s spot on. I’ve lost count of how many times folks focus on windows or doors, but the attic’s where the real trouble hides, especially in older homes with low-pitch roofs. I’ve seen insulation jobs that made a bigger difference than replacing half the windows. It’s wild how much heat loss can happen up there if the underlayment or air sealing isn’t up to par. Sometimes it really is just one overlooked spot causing all the headaches.

It’s wild how much heat loss can happen up there if the underlayment or air sealing isn’t up to par. Sometimes it really is just one overlooked spot causing all the headaches.

That hits home. I used to think it was all about the windows too, but after crawling around my attic and seeing the patchy old felt underlayment, it made sense why the upstairs was always freezing in winter and a sauna in July. Swapping out the underlayment (I went with a synthetic one this time) actually made a bigger difference than the new doors we put in last year.

Did you notice any noise changes after updating yours? I swear the house is quieter now, but maybe that’s just wishful thinking. Also, I’m curious - did you DIY the install or have someone do it? I tried tackling it myself, but the low-pitch roof made it a pain. Still, totally worth it for the comfort boost.

It’s kind of funny - sometimes the “big fix” is just fixing what’s been ignored for years.

Funny you mention noise - I thought I was imagining things, but after switching to synthetic underlayment, it legit feels like the rain isn’t as loud. Maybe it’s just my brain wanting to justify the hassle. I tried DIY too, but my roof’s pitch is basically a slip-n-slide. Never again.

Interesting - I've actually heard the opposite from a few folks, especially with metal roofs. Some say the synthetic stuff almost seems to amplify the sound, like it’s got a drum effect. I wonder if it depends on the type or maybe how tight everything’s installed? Honestly, I’ve crawled around on enough steep roofs to know DIY isn’t for the faint of heart... One slip and you’re regretting all your life choices. But yeah, noise is such a weird thing - sometimes it’s more about what’s underneath than the underlayment itself.

That drum effect you mentioned is real - I've noticed it on a few projects where the synthetic underlayment was stretched super tight under metal panels. Sometimes it almost feels like a snare drum up there in a heavy rain, but other times it's barely noticeable. I do wonder if it comes down to the roof deck material or even attic insulation more than just the underlayment type.

I’ve seen folks blame the underlayment for noise, but then you peek underneath and realize there’s just bare plywood with no insulation at all. That’ll echo every raindrop, no matter what’s on top. And yeah, installation makes a difference - loose spots can flap and make things worse.

Steep roofs are no joke, either. I’ve had my fair share of “what am I doing up here” moments... especially when the wind picks up. Props for tackling it yourself - takes guts and some good boots.

Curious if you’ve noticed any difference in noise with different brands, or is it all pretty much the same in your experience?

Steep roofs are no joke, either. I’ve had my fair share of “what am I doing up here” moments... especially when the wind picks up. Props for tackling it yourself - takes guts and some good boots.

Man, you nailed it with that one. I swear, every time I’m up on a 10/12 pitch and the breeze starts going sideways, I start questioning all my life choices. Good boots and a healthy respect for gravity are a must.

About the drum effect - yeah, I’ve heard it too. First time I noticed it, I thought someone was actually playing drums in the attic. Turns out, just a tight underlayment and a metal roof combo during a downpour. It’s wild how much difference the deck and insulation make. One house I worked on had thick spray foam under the deck, and you could barely hear the rain at all. Next job, same underlayment brand but just plywood and air... sounded like hail even when it was just sprinkling.

I’ve tried a couple brands (mostly whatever the boss grabs from the yard), and honestly, I can’t say I’ve noticed a huge difference in noise between them. Maybe some are a little thicker or have more grip, but if they’re stretched tight under metal, they all seem to get that snare drum vibe when it rains hard. The only time it was noticeably quieter was when we used a felt underlayment instead of synthetic, but that stuff’s a pain in the neck to work with on steep slopes.

You mentioned loose spots - totally agree. Had one section where we didn’t get it tight enough around a vent, and every gust of wind made it sound like a flag flapping. Drove me nuts until we fixed it.

Props for sticking with it and figuring out what works for your setup. Roofing’s one of those things where you learn something new (or weird) on every job. If you find an underlayment that actually kills the drum effect without being a nightmare to install, let us know... might save my sanity next rainy season.

I’ve inspected a lot of metal roofs over the years, and honestly, the underlayment “drum” is one of those things folks underestimate until the first big storm. I’m skeptical that any underlayment alone will fix it - decking and insulation matter way more in my experience. Felt might help a bit, but it’s a pain, like you said. If you want real quiet, spray foam’s about the only thing I’ve seen make a night-and-day difference. Everything else just sort of muffles the noise, not kills it.

Gotta agree, underlayment alone never did much for my place either. I tried a couple “super quiet” brands under my metal roof - still sounded like a drum solo during storms. Ended up biting the bullet on spray foam in the attic. Cost a bit more, but man, it was worth it for the peace and quiet. Honestly, I think folks underestimate how much the whole roof system matters, not just the layer right under the metal.

Honestly, I think folks underestimate how much the whole roof system matters, not just the layer right under the metal.

Couldn’t agree more. I tried three different underlayments under my standing seam roof - felt, synthetic, and one of those “sound deadening” ones. None made a real dent in the noise. Only after adding dense-pack cellulose in the attic did things quiet down. If you’re chasing silence, it’s gotta be a combo approach, not just underlayment. The marketing always oversells that part.

If you’re chasing silence, it’s gotta be a combo approach, not just underlayment. The marketing always oversells that part.

Man, I hear you on the noise thing. After a hailstorm last year, I replaced my underlayment with one of those “premium” synthetics - supposed to be quieter, longer-lasting, all that jazz. Didn’t notice much difference when the rain hit. Ended up stuffing extra insulation in the attic too, which actually helped. Makes me wonder if the underlayment hype is just clever packaging sometimes... but hey, at least it’s holding up better than the old felt ever did.

I’ve been through a couple roof jobs now, and honestly, I think the whole “silent underlayment” thing is mostly marketing fluff. I swapped out old felt for synthetic too - no real difference in noise when it pours. What actually made a dent was blowing in more cellulose up top. The underlayment’s definitely tougher, though, especially in our freeze-thaw cycles. But if you’re expecting peace and quiet, insulation’s where it’s at. The rest is just a bonus.