I stopped insulating with spray foam after that Texas build melted down

Honestly, I used to swear by spray foam insulation for container homes. But last summer I worked on a build in Austin where the guy used closed cell foam on a dark blue container. By August, the interior panels started warping and the foam actually delaminated from the steel. The heat buildup was way worse than I expected, even with a ventilated roof gap. I measured the interior temp at 115 degrees on a 95 degree day. Switched to mineral wool batts with a rigid foam thermal break on that next project and it stayed 20 degrees cooler. Has anyone else had trouble with spray foam in hot climates?

2 comments

2 Comments

betty_shah2d ago

Lol, 115 degrees? That sounds rough but I dunno if that's the foam's fault or just bad planning. Dark blue container in Texas summer is basically a giant radiator, man. I've seen people use spray foam in hot climates down here in Florida with no major issues, but they always pop a light colored roof coating and good ventilation. Maybe your guy just skimped on the prep work?

uma_patel192d agoMost Upvoted

Has anyone checked if the foam was actually meant for that kind of extreme heat range? I've seen some spray foam products that clearly say 'max service temp 140F' on the can, but installers will still use it on a roof that's hitting 160F or more in direct sun. In Florida we get a lot of that 'cool roof' coating talk, but sometimes the real fix is just using a high temp rated foam in the first place. I knew a guy who had his container spray foamed and the stuff melted like butter after one July afternoon, but it turned out his installer used a cheap brand that was never designed for that kind of surface temp. Might be worth asking what exact product they used, because not all foam is built the same.