I have a mid 70's house with exterior gyproc sheathing, and currently alluminum siding (second floor) that needs to be replaced. There appear to have been leaks along the step flashing wall to roof interface onto the garage gyprock cieling ( water has run down the rafter). Step flashing needs to be nailed to something and of course, you can't nail to gyprock. I am planning to re-side with vinyl siding, with a tyvec type material covering and strapping to provide a breathing space between the cladding and the sheathing. I need a detail for the roof to wall interface for the step flashing that needs to be installed. I had not planned to install exterior insulation, but if I do, I need a detail for that. The issue to me for adding insulation to the exterior over a roof interferes with replacing roof sheathing in future, and my understanding that the current building code requires that you do not restrict future maintnence requirements when you make modifications.
Would be please to hear from you!!