Once the membrane gets over 120°F, it’s just a pain no matter what you do. The seams can get weirdly glossy or even bubble if you’re not careful.
Totally agree—120°F seems to be that tipping point where things start acting up. I tried tarps last summer, and honestly, they were more trouble than they were worth with just two of us. Shading the rolls helped more. I did notice, though, if I left my tools in the shade or even in a cooler, it made a difference with the welds. Not perfect, but less hassle with bubbling. The heat just makes everything unpredictable.
I’ve wondered if it’s even worth trying to weld TPO once the temp hits that point. I tried early mornings to beat the heat, but even then, the membrane felt almost tacky by 10am. Has anyone tried those reflective tarps? I thought about it, but worried they’d just trap more heat underneath. Also, is there a trick for checking surface temp besides those cheap IR thermometers? Mine always seems off when the sun’s blasting.
- Good call on working early—honestly, once that membrane’s soft by mid-morning, you’re fighting a losing battle.
- Reflective tarps can help a bit, but yeah, they’ll sometimes trap heat if there’s no airflow underneath. I’ve tried propping them up to get some breeze through, but it’s hit or miss.
- IR thermometers are notorious for being off when the sun’s out. If you can, shade the spot for a few minutes before checking, or use a contact probe if you’ve got one handy. Not perfect, but better than nothing.
- You’re not alone—summer TPO welding is a pain. Sometimes you just gotta call it and wait for a cooler stretch.
Reflective tarps can help a bit, but yeah, they’ll sometimes trap heat if there’s no airflow underneath.
Tried the reflective tarp trick last July—ended up with a sweaty mess and the membrane felt like it was steaming from below. Maybe I just have bad luck, but unless there’s a breeze, it’s almost worse. I’ve started carrying a little folding shade tent for the seam area. Looks ridiculous, but keeps things workable for a few extra hours. Still, when that TPO gets gummy by noon, I’m packing up. Not worth fighting with welds that’ll pop open in a week... learned that one the hard way.
I hear you on the reflective tarp—mine just made everything muggy underneath, too. I actually tried propping it up with some scrap wood to get a little airflow, but it barely helped. That folding shade tent idea sounds smart, even if it looks goofy. Once my TPO started feeling tacky, I called it quits as well. It’s just not worth risking bad seams and leaks later. Summer sun on a flat roof is brutal... sometimes you just have to wait for a cooler day.
