Interesting points about humidity—I hadn't really thought about that angle before. Reminds me of a time we had a roofing crew out on one of those muggy summer mornings. You know, the kind where you step outside and instantly feel like you're wrapped in a wet blanket? Anyway, they were welding TPO, and everything seemed fine at first. But as the day warmed up and humidity climbed, the seams started looking off—like weirdly shiny and uneven. The guys kept adjusting their heat settings, but nothing seemed to help much. Eventually, one of the older guys on the crew mentioned something about moisture getting trapped or something along those lines. They ended up taking a break until conditions improved later in the afternoon.
Made me wonder afterward: is there some kind of sweet spot for humidity levels when welding TPO? Like, obviously too humid is bad news, but is there a lower limit too? I've heard some roofers say overly dry conditions can cause static issues or make the material brittle during welding. Not sure how true that is though... maybe just roofer folklore?
Either way, seems like there's always more to it than just temperature alone. Curious if anyone else has noticed specific humidity ranges that seem ideal—or problematic—for TPO welding.
I've definitely noticed humidity playing a role too. Had a similar experience when we redid our flat roof last summer—crew was struggling on a super humid day, seams looked bubbly and uneven. They mentioned moisture getting trapped under the membrane. Not sure about the lower limit though... static issues sound plausible, but brittle material seems like a stretch. Probably one of those things roofers debate over lunch breaks, haha. Either way, seems like moderate humidity is your friend here.
Humidity definitely can make things tricky... but I'm wondering, is there really a sweet spot for humidity when welding TPO? Like, obviously too humid isn't great (bubbles and trapped moisture—been there, done that). But is there a point where it's actually too dry? I've heard a roofer buddy mention static buildup causing issues, but I always thought he was just exaggerating for effect, haha.
Also curious about the brittle material thing you mentioned—does anyone actually have firsthand experience with TPO becoming brittle in low humidity or colder conditions? Seems like something you'd only notice in extreme cases. Either way, moderate humidity does seem to be the safest bet. Maybe roofers should start carrying hygrometers along with their heat guns... just kidding (sort of).
I've never personally seen TPO get brittle strictly from low humidity, but cold weather is another story. Had a job last winter where the sheets felt noticeably stiffer and harder to weld cleanly—had to slow down quite a bit. As for static buildup, your buddy isn't completely off-base. I've had days when it was super dry and noticed some weird static cling with dust and debris sticking to everything, definitely didn't help weld quality. Not a common issue, but it's real enough to notice occasionally...
Interesting points about the static issue—I remember one particularly dry day when I swear the TPO was attracting every speck of dirt in a 5-mile radius. Felt like I was welding sandpaper, haha. Regarding temperature though, I've noticed if you push it too hot, the seam edges start looking glossy or even scorched. Curious if anyone else has found a sweet spot temp-wise that works consistently across different brands? Seems to vary more than you'd expect...
