I added a shed dormer to the back of a 2nd story, with a 2:12 built-up roof over the dormer. The 2:12 goes all the way to the ridge. The front has asphalt shingles on 7:12 pitch. I wanted to install a ridge vent, but decided that would invite leaks at the ridge. How do I properly cap the ridge, with built-up on one side and shingles on the other?
I have thought nailing the ridge cap shingles on the shingle side and using roof adhesive on the other side. I don't like the idea of nailing into the BUR, but would like advice.