I had a small chase to use to run duct to a mud and laundry room. The space is approx 7" hi(there is no attic here, just this space between the ceiling and roof). We fabbed a 6.5" tall trunk to slide into the space and cut in supply and short flex to the rooms.
The 6.5" hi duct is insulated on the inside and is very close(1/4" ) to the 3/4 ply that makes up the roof deck. Will this present a problem with condensation, or any thing else you all can think of? I have the drywall down in that ceiling area and have noticed no issues, but I am installing 6" of batts and getting ready to hang rock.