Frustrated trying to pick roof decking materials

"Curious though if anyone here has experience combining radiant barriers or reflective underlayments with a green roof... seems like it could be an interesting combo for managing moisture and heat."

Actually, I helped a friend install a green roof a couple years back, and we did experiment a bit with radiant barriers underneath. Honestly, the difference wasn't huge - it seemed like the vegetation and drainage layers were already doing most of the heavy lifting when it came to temperature control. Moisture-wise, we didn't see any noticeable improvement either way with the reflective stuff.

But yeah, totally agree on ditching OSB if moisture's your main headache. I've seen enough swollen OSB boards to last me a lifetime, lol. Green roofs are great, but make sure your structure can handle the extra weight. If you're worried about load-bearing capacity, plywood decking might still be your safest bet underneath all that greenery.

Have you thought about what plants you'd use yet? Sedums are pretty forgiving, but I've seen some really cool setups with native grasses and wildflowers too...

"Honestly, the difference wasn't huge - it seemed like the vegetation and drainage layers were already doing most of the heavy lifting when it came to temperature control."

Yeah, I think this is spot-on. I've been part of a couple green roof projects myself, and from what I've seen, once you've got a solid vegetation layer established, the radiant barrier doesn't really add much value. The plants and soil already do a pretty impressive job regulating heat and moisture. If anything, I'd put more effort into making sure your drainage and waterproofing layers are top-notch, since that's where I've seen most issues pop up over time.

And totally agree about OSB - it's cheap upfront but can end up costing you way more in headaches down the road. I've had to rip out swollen, moldy OSB decking before, and trust me, it's not something you wanna deal with twice. Plywood might cost a bit more initially, but it's definitely worth it for peace of mind.

As far as plants go, sedums are definitely the easiest route - super hardy and low-maintenance. But if you're feeling adventurous, native grasses or wildflowers can look amazing and even attract pollinators. Just keep in mind they'll probably need a bit more attention at first to get established. A friend of mine did a mix of native grasses and sedums, and it turned out pretty awesome. Took a bit of experimenting to get the balance right, but now it's thriving and looks great year-round.

Anyway, sounds like you're on the right track. Green roofs can be a bit of a hassle to plan out, but they're totally worth it once they're up and running. Keep us updated on how it goes...

Yeah, good call on the OSB - I’ve seen way too many decks ruined by moisture issues. Curious though, did your friend have any trouble with weeds popping up in the native grass mix? Seems like that could get tricky...

Weeds weren't too bad actually, at least from what I've seen. My neighbor did a native grass mix a couple years back - he was worried about weeds too - but after the first growing season things filled in pretty nicely. He did spend some weekends early on hand-pulling a few stubborn ones, but nothing crazy. Honestly, the bigger headache was keeping the birds away from the seed long enough for it to establish.

I've been thinking about doing something similar myself, but I'm still on the fence. It looks great once it's established, but that initial maintenance isn't exactly my idea of fun. Plus, knowing my luck, I'd probably end up with nothing but crabgrass and dandelions...

Yeah, I hear ya about the weeds. My sister did a wildflower mix last spring, and she had a similar experience - mostly just minor hand-pulling at first. Honestly, I'd be more worried about the birds too...those little guys treat seed like it's an all-you-can-eat buffet.