9×18 enclosed porch area with a shed roof.
What I’d like to do is raise the 7ft exterior wall to 10ft by resting two 8×8 horizontal 18ft barn beams on 10ft 8×8 verticals at the corners,
two other 8×8 vertical 10s sitting mid span exposed to the interior. Same 9ft horizontals running across joining the verticals.
12ft 2x roof joists running from the house at a walkable pitch creating a deep overhang. 3/4inch t&g OSB sheathing with shingles.
Can I place 2 inch DOW blueboard on top of the roof joists and screw the OSB with 4inch screws?
If going with 2x8s will 24inch on center suffice? If 16″ on center will 2x6s work ok?