>>23389263There is a very particular code for how to hang flex duct and almost no installers ever follow it to the letter because it's a pain in the ass to do, but this is how you do it properly.
Secure the hanging strap to the outside of an adjacent roof joist (DO NOT NAIL INTO ROOF PANEL. JOISTS ONLY!). Loop the hang strap around the duct once, and gently pull it tight up to the other joist. Use the looped strap to adjust exactly where the duct needs to sit so it's straight, level and pulled tight. No scrunches in insulation! Gentle 90 degree turns. Secure the duct once per every two joists of distance.
I almost guarantee those mexicans didn't do this. It's totally possible for a homeowner to do it DIY, but i will warn you it will be a giant PITA
