Had a similar experience last July up in Oklahoma—wasn’t Texas-hot, but still brutal. We tried to push through a big install on a white TPO and by 11am, the seams were bubbling like pizza cheese. Ended up scrapping half a day’s work because the welds just wouldn’t hold. Since then, I’m all about early starts and sometimes even night work if it’s safe. It’s just not worth risking those failures down the line, especially when you’re trying to keep things green and efficient.
by 11am, the seams were bubbling like pizza cheese. Ended up scrapping half a day’s work because the welds just wouldn’t hold.
That “pizza cheese” look is all too familiar. I’ve seen TPO get so soft you can leave a thumbprint just walking across it. I get the push to keep schedules, but honestly, I’ve never trusted welds done after the membrane’s been baking for hours. Even with fancy IR thermometers, you can’t always tell what’s happening under the surface. Early starts help, but I’ve had crews try night work and run into dew issues—seams looked fine until the next afternoon, then started peeling. Sometimes feels like you’re picking your poison with summer installs.
Sometimes feels like you’re picking your poison with summer installs.
Ain’t that the truth. I’ve watched guys try to beat the heat by starting at sunrise, but by 10:30, the roof’s already hot enough to fry an egg. I’ve had TPO seams look perfect in the morning, then by lunch, they’re bubbling up like a bad lasagna. Tried night work once—figured it’d be cooler, but the dew snuck in and made everything slippery and weird. Next day, seams started peeling up like stickers on a kid’s lunchbox.
Honestly, I don’t think there’s a magic number for “too hot,” but if you can’t touch the membrane for more than a second without yanking your hand back, it’s probably time to call it. I’ve heard some folks swear by using a scrap piece to test welds before committing, but even then, it’s a gamble. Summer installs are just a headache—sometimes you win, sometimes you’re scraping off gooey seams and cursing the sun.
I’ve run into the same issues during summer projects—one building in particular, we tried to schedule around the heat, but even starting early didn’t help much. By mid-morning, the surface temp was way higher than the air temp, and welds just wouldn’t hold. Has anyone actually measured the membrane temp versus air temp? I’ve wondered if using an IR thermometer would help predict when it’s just not worth pushing through. Or is it more about humidity and wind too? It always feels like a guessing game.
Man, I hear you on the guessing game. TPO in the summer is like trying to weld on a frying pan—sometimes literally. I’ve actually used an IR thermometer a few times, and it’s wild how much hotter the membrane gets compared to the air. One time, air temp was 88°F but the TPO was pushing 140°F by 10am. No wonder the seams looked like melted cheese.
Humidity and wind definitely play a part, but honestly, surface temp is the big one for me. If there’s no breeze and the sun’s beating down, I just accept defeat and call it a coffee break. I’ve tried shading sections with tarps, but that only helps a little. At some point, you’re just fighting physics.
Don’t beat yourself up—sometimes it’s just not possible to get a good weld in those conditions, no matter how early you start. If you figure out a magic trick for this, let me know... until then, I’ll be hiding under the nearest vent stack when it gets too spicy up there.
