I like the idea of mixing it up—felt in the “trouble spots” just sounds safer. I’d rather be a little old-school than wake up to a drip in the attic, you know?
I get where you’re coming from, but honestly, I’ve seen synthetic underlayment hold up better than felt in some of those tricky spots, especially around chimneys and valleys. Felt can bunch or wrinkle if there’s any moisture during install, and then you’re just trapping problems under your shingles. I know it’s tempting to go “tried and true,” but the newer synthetics are way tougher against wind and water—at least the good brands.
That said, I totally get the paranoia about leaks. My last place had a slate roof from the 1920s and every patch job was a gamble. Still, I’d lean toward one material for consistency unless your roofer really knows how to transition between them without creating a weak spot. Mixing materials can sometimes make things worse if it’s not done right... just my two cents from seeing a few too many patchwork disasters.
Mixing underlayments isn’t always a disaster, though. I’ve seen some older homes where felt in the valleys actually outlasted the synthetic everywhere else—guess it depends on climate and how careful the install is. Sometimes “old-school” just works, quirks and all.
I’ve noticed that too—sometimes the “tried and true” materials just hold up better, especially in tricky spots like valleys. I lean toward felt in those areas for older homes, mostly because it seems to breathe better and handle weird moisture issues. Synthetic’s great, but it’s not always a one-size-fits-all solution. Just depends on what you’re working with, honestly.
Title: Need advice on replacing an old leaky roof
I get where you’re coming from—felt does have its place, especially in those older homes with odd ventilation. That said, I’ve found that some of the newer synthetics can outperform felt in terms of durability, especially if you’re dealing with a low pitch or a spot that’s prone to pooling. It really comes down to the roof’s structure and how much moisture you’re expecting. On a recent project, we actually mixed both—synthetic for the main field, felt in the valleys—and it worked out well. Sometimes a hybrid approach just makes sense.
I get the appeal of mixing materials, but I’m a bit wary about using felt in valleys. In my case, the felt didn’t hold up well after a couple of winters—ice dams just tore it up. Switched to all synthetic last time and haven’t had issues since. Maybe it depends on the climate or just luck, but I’d lean toward full synthetic if you’re already redoing everything.