"Curious if anyone's actually measured surface temps side-by-side to confirm this."
Funny you mention that—I actually did a quick test with my mentor last summer. We had some leftover TPO scraps, one white and one gray, and decided to see if color made any noticeable difference. We laid them out side-by-side on a sunny day for about an hour, then checked the surface temps with an infrared thermometer before welding.
Surprisingly, the darker membrane was around 15-20°F hotter than the white one. But here's the thing: once we started welding, that initial temp difference didn't seem to matter much at all. The welder's heat is so intense it pretty much overrides any minor variations from sunlight absorption.
In my experience, what really matters more is dialing in your welder settings correctly—speed, airflow, and temperature—and making sure your seams are clean and prepped properly. Membrane thickness and brand quality definitely play a role too...I've noticed cheaper membranes can be trickier to weld consistently.
So yeah, color might affect initial surface temps slightly, but practically speaking, it's probably not something you'll notice much when you're actually welding.
Interesting test you did there. I've wondered about this myself, especially since I'm considering a darker membrane to match my home's exterior. But if the welder's heat overrides the initial temp difference anyway, does it even matter much practically? Seems like focusing on quality materials and proper welding technique might be the smarter move... Glad you shared your experience, helps clear things up a bit.
Good points—I was actually wondering something similar. I'm pretty new to all this roofing stuff (first-time homeowner here), and I went with a lighter membrane just because the contractor recommended it. But now I'm curious: even if the welding heat overrides the membrane's initial temp, wouldn't a darker color still absorb more heat over time? Like, could that affect the longevity or performance of the roof in the long run?
I guess what I'm getting at is, even if welding technique is key, maybe color choice still matters practically for other reasons... like energy efficiency or durability? Just thinking out loud here, since I'm still figuring all this out myself.
"But now I'm curious: even if the welding heat overrides the membrane's initial temp, wouldn't a darker color still absorb more heat over time?"
That's actually a pretty insightful thought. Welding definitely sets the membrane at a high temp initially, but you're right—color could still matter in the long run. I've seen roofs where darker membranes seem to age differently, maybe because they're absorbing more sunlight and heat day after day? I'm still learning too, but I remember one of the older guys on our crew joking that dark roofs are basically "sun magnets," haha.
Energy efficiency-wise, lighter colors do reflect sunlight better, which can help keep your place cooler and potentially lower your AC bills. Durability might be trickier—I haven't noticed a huge difference myself yet, but it makes sense that less heat stress could mean fewer cracks or issues over time.
Anyway, good call bringing this up... I'm gonna ask around at work tomorrow and see what the experienced guys think. You've got me curious now too!
Interesting points here, but honestly, I'm not totally convinced color makes a huge difference once you're welding at those temps. I mean, yeah, darker roofs definitely soak up more sun over time—my neighbor's black roof is like walking on lava in July, no joke. But when you're welding TPO, you're already hitting temps way beyond normal sunlight exposure, right? Seems like the initial welding heat would overshadow any minor heat absorption differences from color.
That said, I do agree lighter colors probably help with energy bills down the road. When we replaced our roof last year, we went with a lighter membrane, and the attic feels noticeably cooler now. Can't speak much to durability yet—still early days—but it makes sense that less heat stress might help things last longer.
Anyway, just my two cents as someone who's recently been down the roofing rabbit hole...
