Yeah, I’ve noticed those temp strips don’t always tell the whole story—especially when the roof’s been baking all day. I’ve tried to save a buck by working early mornings or later in the day, and honestly, my seams look way better. Not sure I trust my “gut” every time, but watching for that glossy look on TPO has saved me from some ugly welds. Definitely less stress when you’re not fighting the heat… plus, I don’t end up frying myself in the process.
I get the appeal of working early or late, but honestly, I’ve had some seams come out worse when the roof’s still holding heat from the day before. Even in the morning, that membrane can be hotter than you think. I started using a cheap infrared thermometer—nothing fancy—and it’s helped me avoid guessing. The glossy look is good, but sometimes it’s too late by then... burned a few spots learning that lesson. For me, checking the actual temp before starting saves time and materials in the long run.
That’s interesting—do you find the membrane temp is usually higher than the air temp, even early? I’ve always wondered if there’s a sweet spot for surface temp, or if it really just depends on the brand or thickness of TPO. Have you noticed any difference between white and gray membranes in terms of how fast they heat up or cool down? I’m curious if anyone’s tried shading sections before welding, or if that’s just overkill.
I’ve only worked with white TPO, so can’t speak for gray, but I’ve definitely noticed the membrane gets hotter than the air pretty early in the day—especially on those clear, sunny mornings. I started using an IR thermometer after burning a couple of seams my first go-around. What surprised me is how much the surface temp can jump just from a cloud moving or the sun shifting. Sometimes it’s 10-15 degrees hotter than what the weather app says.
I tried shading a section once with a big piece of cardboard, but honestly, it felt like overkill and didn’t seem to make a huge difference unless you’re working in direct sun at noon. For me, the sweet spot is usually when the surface is just warm to the touch, not hot enough to make you pull your hand back. I’m still skeptical about how much brand or thickness matters—maybe a little, but sun exposure seems to be the biggest factor. If you’re worried about overheating, I’d say work early or late in the day and keep that temp gun handy.
- I’ve noticed the same thing with surface temps jumping all over the place, especially on white TPO. Even a little haze can drop it fast, but direct sun just cooks it.
- I’ve tried both white and gray—gray definitely gets hotter, but not by as much as I expected. Still, I stick to white for most jobs just for that reason.
- Cardboard shade trick is clever, but yeah, unless you’re working right at noon, it’s a hassle to keep moving it around.
- For me, the “hand test” is pretty reliable—if you can’t keep your hand on it for a few seconds, it’s probably too hot to weld cleanly.
- Brand and thickness… I’ve seen some difference with thicker membranes holding heat longer into the afternoon, but not enough to change my schedule.
- Early mornings or late afternoons are my go-to windows too. Sometimes I’ll even split a job over two days if the forecast is brutal.
Curious if anyone’s tried those reflective tarps or temporary covers? Wondering if they’re worth hauling up there or just more trouble than they’re worth...
