Should exterior sheathing, the air / water barrier and outboard ridged insulation extend over the top of parapets and tie into the same on the opposite side of the wall?

Although this can be a challenge with attachment of wood blocking, it is best to enclose all exterior sheathing with the air / water barrier for continuous outboard insulation wall systems.

In cases where the UL for rated roof requires exterior rated sheathing laid on the metal deck the air /water barrier can continue under the roof insulation but must meet roofing system warranty.