I looked into this stuff before and passed. From everything I read about these aluminum coatings is that they do not do what you might think they do with RVs.
I know it alludes to waterproofing but everything I could find out says this stuff DOES NOT waterproof. It’s essentially an anti corrosive, uv protecting restorative paint.
If you want the waterproofing then you need to use the membrane that Resisto makes, that is where you will get water protection.
If you know already then carry on but if not, google a bit about aluminum roof coatings.