Stop in for a cup of coffee

I'm not sure what is 'accepted' practice for a flat with metal on residential. Probably not something they encounter much. On cold storage we had rubber sheet lapped a foot up the side and cemented. I'd have that area sealed up like a swimming pool!
We use frost shield a course or two close to the gutters. I think this area is up where 2 or 3 valleys meet. They should have used it but I don't know for sure. Like I mentioned, there is a strange little flat roof area up there that can't be seen from the ground.