Underlayment and Steel Roof Covering-- Metal Roof 101 with Todd Miller
https://www.storeboard.com/blogs/general/pros-and-cons-of-spray-polyurethane-foam/2292719
These roofing systems can reach very high temperatures as a result of the low reflectivity, high absorption, as well as high conductivity of the metals. Call your GCP Applied Technologies sales rep for help selecting