Cover boards can definitely help, but insulation-wise, I've found that polyiso foam boards underneath the modified bitumen layer make a noticeable difference. Worked on a project a few years back where the owner initially skipped insulation to save money—big mistake. After one winter, heating bills shot up and they ended up retrofitting polyiso anyway. Not cheap either, but it paid off in comfort and energy savings over time. Just something else to consider if you're looking at long-term solutions...
"After one winter, heating bills shot up and they ended up retrofitting polyiso anyway."
Yeah, I've seen that happen more times than I'd like to admit. But I'm curious—have you ever tried combining polyiso with a reflective coating on the modified bitumen itself? Did a job last summer where we did exactly that, and the owner swears it made an even bigger difference. Might be worth looking into if you're chasing long-term savings...
Interesting point about the reflective coating, but I'm wondering if that's really as effective in colder climates? From what I've read, reflective coatings are great at reducing heat gain in summer, but wouldn't they potentially reduce beneficial solar heat gain during winter months? I mean, polyiso alone already has a pretty solid R-value, so adding reflectivity might not always be beneficial depending on your local climate conditions.
I worked on a project last year where the owner specifically avoided reflective coatings because they wanted to maximize passive solar heating during winter. They ended up going with thicker polyiso insulation instead and seemed pretty satisfied with the results. Maybe it's more about balancing insulation thickness and reflectivity based on your specific seasonal needs rather than just stacking solutions?
Not saying reflective coatings don't have their place—they definitely do—but it might be worth considering whether they're always the best choice for every region or building type...
"Maybe it's more about balancing insulation thickness and reflectivity based on your specific seasonal needs rather than just stacking solutions?"
Good point—it's definitely not a one-size-fits-all thing. Seen plenty of roofs where thicker insulation alone did the trick, especially in colder climates. Always smart to tailor solutions to local conditions...
Yeah, totally agree it's about finding the right balance. When I bought my place, the previous owner had just piled on thick insulation without considering reflectivity or ventilation. Summers were brutal—heat got trapped and turned the attic into an oven. Ended up adding a reflective coating later, and it made a huge difference. Like you said:
"Always smart to tailor solutions to local conditions..."
Definitely learned that one the hard way...
