Did you know shingles get layered like fish scales?

That’s wild about your neighbor’s roof - seen a few like that after big gusts, and it always comes back to how those layers were put down. I’ve only worked with synthetic underlayment so far, and yeah, nearly slid off once when the sun was baking it. Curious if anyone’s tried those “grippy” versions they advertise? Also, for valleys, do you guys prefer weaving shingles or using metal flashing underneath? I’ve heard arguments both ways but haven’t seen enough jobs to know what really holds up.

yeah, nearly slid off once when the sun was baking it

Man, I know that feeling - synthetic’s like an ice rink when it heats up. I tried one of those “grippy” underlayments last summer, and honestly, it helped a bit but still not foolproof. For valleys, I’ve mostly seen metal flashing used around here (Midwest), especially after a few woven ones started leaking after heavy rains. Still, some old-timers swear by weaving. Guess it depends on the roof pitch and how much weather you get.

Yeah, I’ve noticed the same thing - synthetic underlayment can be sketchy when it’s hot out. The “grippy” stuff helps, but I still get a little nervous on steeper pitches, especially midday. Metal flashing in valleys seems to hold up better where I am too (Pacific Northwest), but I do wonder about the environmental impact of all that metal versus woven methods. Ever tried any recycled or eco-friendly options for valleys? I’ve been curious if they actually hold up or just sound good on paper.

That’s a really interesting point about the environmental impact of all that metal flashing in the valleys. I’ve been wondering the same thing, honestly. Where I’m at (just outside Seattle), metal is kind of the default for valleys because of all the rain, but I get why it feels like overkill sometimes. It’s super durable, but yeah, it’s a lot of material.

I haven’t had a chance to work with any recycled or eco-friendly valley products yet, but I’ve seen a few brands pitching recycled rubber or composite options. The thing is, I’ve heard mixed reviews from some of the older guys on site. One foreman told me they tried a recycled rubber valley liner on a couple houses and it started curling up after two seasons - granted, that was a few years back, so maybe things have improved since then. Another guy said he used a woven synthetic valley and it actually held up pretty well, but installation was trickier and you had to be careful not to nick it with your tools.

I totally get being nervous on steep pitches with synthetic underlayment too. Even with the “grippy” stuff, it can feel like you’re skating if it’s hot and your boots are dusty. I’ve started double-checking my harness more often, especially after lunch when things heat up.

Honestly, I think there’s still a bit of trial and error with these eco-friendly options. They sound great in theory, but until there’s more long-term data (especially in wet climates like ours), I’d probably stick with metal for now if durability is the top concern. Still, I’d love to see more real-world feedback - maybe someone here has tried something new that actually works? It’d be cool if there was a solid recycled option that didn’t sacrifice performance.

Anyway, good on you for thinking about the environmental side of things. It’s easy to just do what everyone else does without considering the bigger picture.

Shingles really do go on like fish scales, but I’d argue fish don’t have to deal with the HOA or Seattle rain. I’m just outside Tacoma and yeah, metal valleys are everywhere here too. When I replaced my roof five years ago, the roofer practically laughed when I asked about alternatives - said if I wanted to avoid leaks and headaches, stick with metal. He did mention there were some newer “green” options floating around, but he hadn’t seen one that could handle our soggy winters for more than a couple years.

I get the appeal of recycled rubber and composite stuff, but man, curling after two seasons sounds like a nightmare. My last place had some kind of experimental valley liner (I think it was a woven synthetic?) and it worked okay for a while, but installation was definitely fussier than just slapping down metal. Plus, every time we had a windstorm, I’d end up on the roof checking for loose bits. Not exactly confidence-inspiring.

And you nailed it about the underlayment - those “grippy” synthetics are only grippy until you get a little moss or dust on your boots. Nearly slid off the garage roof once trying to be clever and save time... lesson learned.

If someone comes up with a recycled option that’s as tough as metal and doesn’t turn into lasagna noodles after two winters, sign me up. Until then, I’ll keep recycling cans and bottles and let my valleys stay old-school. At least the squirrels seem to appreciate it - they’ve never chewed through metal (yet).