Don't want to scare anybody with a picture of me !
About the roof - When I was in high school Dad and I tore off the roof in the house we were living in.
I'm not sure how many layers, but the last nails used were 3" and had not touched the roof sheeting boards. This was in upstate NY where we got SNOW -- I know the house had full 2"x4" hardwood studs and were full length from sill plate to attic. The 2nd floor joist were notched into the studs. We were told that the first owner / builder owned a lumber mill.