Originally Posted by DIYer
Yes, that cleared up some confusion. I was not planning on running the joists all the way back to the top of the exterior wall. I was just going to tie into the trusses. That is why I subtracted the 1.5'. Is this a bad idea?
On another note. I still don't understand why I would need to remove shingles. Is it becasue of your scenerio of running the joists to the top of the exterior wall?
No your truss/rafter tail cannot support anything, that is why you will need to rip into the roof a little, and while your add it you can add headroom by tieing in higher on exisisting roof.
For removing shingles, when water runs down your exisisting roof and gets to the new roof that is a spot that needs some flashing. The flashing or rubber or roll roofing would run about 2' above the new roof line.