- Price is my main concern, so I keep wondering if synthetics are really worth the extra cost over felt.
- I’ve heard about the slippery thing too—one neighbor’s roofer actually slipped and dinged up a gutter, but maybe that was just bad luck or a rushed job.
- The sealing around fasteners has me worried as well, especially since my place has some pretty uneven old boards under there. If water gets in, I’m back to square one.
- Does synthetic actually last longer in real-world conditions? Like, not just what the brochures say... I don’t want to pay more just for it to fail in five years.
- Anyone try mixing both—felt in tricky spots, synthetic elsewhere? Or is that asking for trouble?
NEED ADVICE ON REPLACING AN OLD LEAKY ROOF
- Totally get the price worry—felt's way easier on the wallet, but I keep seeing people say it just doesn't hold up as well if things get rough (wind, storms, whatever).
- The slippery thing freaks me out too. My cousin’s crew had a guy nearly slide off because of synthetic underlayment. Maybe it’s just about being careful, but still...
- Fastener leaks are my nightmare. My decking's not exactly smooth either, so I’m worried water will find any little gap.
- As for lifespan, I hear synthetic is supposed to last longer, but like you said, is that just marketing? Hard to tell unless you know someone who's had it for a decade or more.
- Mixing them seems smart on paper, but I’ve heard roofers grumble about that—something about weird seams or moisture getting trapped? Not sure if it’s a real risk or just them wanting to keep it simple.
Honestly, I’m leaning toward felt just because of cost, but I keep second guessing myself...
NEED ADVICE ON REPLACING AN OLD LEAKY ROOF
Felt’s definitely easier on the budget, but you’re right to be cautious about longevity. In my experience, traditional #30 felt can do the job if it’s installed well and the roof isn’t going to sit exposed for long. But if you’re in an area that gets a lot of wind or heavy rain, synthetic underlayment does hold up better—especially if there’s any delay before shingles go on. The slip factor is real, though. Some synthetics have a textured surface to help with traction, but it’s never quite as grippy as felt.
Fastener leaks are more about installation than material. If your decking isn’t smooth, make sure whoever’s installing it uses cap nails and doesn’t overdrive them. That’ll help keep water out, regardless of underlayment type.
Mixing felt and synthetic can cause issues at the seams—moisture can get trapped if they overlap wrong, and most roofers I know avoid it unless there’s a really good reason.
If cost is the main concern and you’re not expecting the roof to be exposed for days, felt’s fine. Just don’t skimp on the install details. That’s usually where things go sideways.
NEED ADVICE ON REPLACING AN OLD LEAKY ROOF
I get where you’re coming from on felt being fine if you’re not leaving it exposed, but I’ve seen too many jobs where even a short rainstorm sneaks in before shingles go down and suddenly you’ve got swelling or soft spots in the decking. Maybe that’s just bad luck, but it’s made me a lot more cautious about using felt unless I know for sure the weather window is solid.
On the synthetic side, I actually think the slip factor is a bit overblown—at least with some of the newer brands. We’ve used GAF Deck-Armor and Owens Corning ProArmor on a few steep pitches, and as long as you’re not wearing slick-soled boots, it’s manageable. Not saying it’s perfect, but I’d rather have that tradeoff than risk felt tearing in a gusty wind.
One thing I’d push back on is the idea that fastener leaks are mostly about install. Sure, technique matters, but I’ve noticed synthetics tend to “self-seal” around cap nails better than felt does. Maybe it’s just the way the material flexes? Either way, we’ve had fewer callbacks for leaks since switching over.
Mixing underlayments—yeah, that’s asking for trouble. Had a repair job last year where someone tried to patch with synthetic over old felt and it wicked water right into the seam. Ended up costing more to fix than if they’d just replaced the whole run.
If budget’s tight, I get sticking with felt, but I’d at least price out some of the entry-level synthetics. Sometimes the cost difference isn’t as big as folks expect once you factor in labor and potential rework. Just my two cents...
NEED ADVICE ON REPLACING AN OLD LEAKY ROOF
I get why folks are leaning hard into synthetics lately, but I’m not convinced they’re the silver bullet everyone wants them to be. I’ve seen some of those “self-sealing” claims fall flat in real-world conditions, especially when temps swing or you get a weird batch of cap nails. Felt’s not perfect, but at least you know what you’re dealing with—plus, if you’re careful with install and timing, it’s worked for decades. Sometimes I wonder if we’re just trading one set of problems for another with all these new products.