Sometimes you just have to bite the bullet and reschedule or throw up some shade if you can swing it.
That’s pretty much been my experience too. I tried pushing through a 90+ degree day last summer—figured we’d just slow down, keep the welders on the low end, and hope for the best. Didn’t matter. The TPO was practically melting before we even hit it with the gun, and the seams looked like they’d been chewed up. Ended up having to redo a whole section because the inspector flagged it for voids.
I know deadlines are brutal, but honestly, I’d rather deal with an annoyed GC than callbacks for leaks or warranty headaches. Shade tents help a little, but on big open roofs, it’s not always practical. If the surface is too hot to touch for more than a second or two, I just call it. Not worth risking the whole job over a few hours of lost time.
If the surface is too hot to touch for more than a second or two, I just call it.
That’s honestly the best rule of thumb I’ve found too. I’ve tried using IR thermometers, but even then, the membrane can get weirdly soft way before you hit the “official” limit. Ever tried cooling the seams with wet towels? Sometimes helps, but usually just delays the inevitable. Deadlines are rough, but callbacks are worse—totally agree there.
If the surface is too hot to touch for more than a second or two, I just call it.
That’s pretty much what I go by too, but I’ll admit I’m always a little skeptical about the “touch test.” I’ve had crews with hands like leather who’ll say it’s fine, and then the next day we’re dealing with bubbling or seams that didn’t take. IR thermometers are supposed to help, but like you said, the readings can be all over the place—especially if the sun’s beating down or there’s a breeze.
I’ve seen the wet towel trick used a few times. It does seem to cool things off for a minute, but I always wonder if it’s just masking the problem. Have you ever had issues with condensation getting trapped when you do that? One time we tried it on a big job in July, and we ended up with some weird moisture blisters under the membrane a couple weeks later. Not sure if that was the towels or just bad luck with humidity.
Deadlines are always a pain, but callbacks are worse, no argument there. I’d rather have the crew wait an hour for things to cool off than risk redoing half the seams. Still, I get pushback from contractors who swear they’ve “done it hotter before.” Maybe they have, but I’m not convinced it’s worth the risk.
Curious if anyone’s actually found a reliable way to measure surface temp that accounts for all the variables—sun, wind, even the color of the TPO? Seems like every job is a little different. For now, I just keep an eye out for soft spots and trust my gut more than any gadget. Not perfect, but it’s saved me from a few headaches.
I’ve had the same thing happen with the wet towel trick—looked fine at first, then a week later, blisters everywhere. I’m starting to think it’s more trouble than it’s worth, especially on humid days. Has anyone tried those surface temp stickers? I’ve seen them on some jobs but never used them myself. Wondering if they’re any more reliable than the IR guns or just another gimmick.
I’ve wondered about those temp stickers too. I see them on some bigger commercial jobs, but never on any residential work around here. I’ve always used an IR gun, but honestly, I don’t totally trust it—sometimes I get readings that just don’t make sense, especially if the sun’s hitting the membrane at an angle or the surface is a little dusty. The stickers seem like they’d be more “set it and forget it,” but are they actually accurate once the heat gun’s blasting away? Or do they just give you a ballpark?
Also, has anyone had luck with just going by feel? I know it sounds old-school, but my neighbor swears by running his knuckle along the seam and says he can tell if it’s too hot or not. I’m not that brave, but maybe there’s something to it. Curious if anyone’s found a method that actually prevents those blisters long-term, especially when the humidity’s up.