I've used modular trays on a mid-sized apartment building, and they held up pretty well. Agree on the watering though—ended up installing a basic drip irrigation system to manage that. Wasn't expensive or complicated, just a simple timer setup. Definitely easier than structural reinforcement, and tenants appreciated the green touch. Something to consider if you're worried about maintenance...
Interesting to hear the drip irrigation wasn't much hassle... but does it hold up in colder climates? I've been eyeing these modular trays for my roof, just not sure if winter frost would mess things up or not. Any experiences?
I've used modular trays for green roofing in a pretty chilly climate (think Midwest winters, plenty of snow and ice), and honestly, they've held up surprisingly well. A couple of things to keep in mind though...
First off, make sure the trays you're looking at are made from durable materials—usually recycled plastics or something similar. Cheaper trays can get brittle when temperatures drop below freezing, and that's when cracking happens. I learned this the hard way with my first attempt; went budget-friendly and ended up replacing half of them after just one winter. Not fun.
Second, drainage is key. If water pools in the trays and freezes solid, that's when you get expansion and cracking issues. Good modular trays usually have built-in drainage channels or holes, but double-check that they're sufficient for your area's rainfall and snowmelt. I actually drilled a few extra holes in mine just to be safe, and it made a noticeable difference.
Also, consider your planting choices carefully. Hardy sedums and alpine plants handle frost like champs, but some other plants might not survive harsh winters. Picking the right plants can save you a lot of hassle come springtime.
Lastly, don't stress too much about frost itself damaging the trays if they're decent quality. I've had mine up for three winters now, and aside from that initial mistake with cheap trays, no issues at all. Just do a quick inspection each spring—takes maybe half an hour—to spot any minor cracks or damage early.
Overall, I'd say go for it if you're leaning toward modular trays. They're pretty forgiving once you get the basics right, and the benefits definitely outweigh the minor maintenance. Plus, there's nothing quite like seeing green popping up on your roof after a long winter... makes it all worthwhile.
"Second, drainage is key. If water pools in the trays and freezes solid, that's when you get expansion and cracking issues."
Totally agree drainage is important, but honestly, even with extra holes drilled, I still had issues with ice buildup. Maybe it’s just my roof angle or something... ended up switching to a lightweight green roof mat instead. It's held up better for me through winter, and zero cracking worries. Modular trays are great, but mats might be worth considering too if winters get really harsh.
Interesting point about the mats—I’ve seen them hold up surprisingly well too. I remember a client who had modular trays installed, and despite having pretty solid drainage, they still ended up with ice dams forming underneath. Turned out their roof had just enough slope to let water trickle down slowly, but not enough to really clear it out before freezing temps hit. We tried tweaking the angle slightly, but honestly, it was a bit of a losing battle...
Eventually, they switched over to mats similar to what you mentioned. The mats seemed to handle freeze-thaw cycles better without cracking or warping—probably because they're more flexible and don't trap water as easily. So yeah, trays are great in theory, but roof angle and climate make a huge difference. Mats can definitely be an underrated option if your winters get harsh enough or your roof pitch is tricky.
