Here is another picture showing the insulation and how it connects to the grate that I showed in one of the original pictures. I don’t see any rot or anything like that but it’s also never had heat running in it before, which I assume would make things worse. The fact it leads straight to where the insulation with no gap or anything feels all kinds of wrong… Would something like baffles be helpful? I could potentially push them behind the insulation to open a gap between the roof deck and insulation.
I had to take down a horrible staircase one of the previous owners stuck in which was put in seemingly before sheet rock so the sheet rock was fitted to the stairs which lead to holes in the sheet rock. The one I took the picture out of is part of that.
What do you mean by horizontal and avoiding “thermal bridging” if you have any diagram that could possibly help I would appreciate it. I figure if I am going to fix up the structure I might as well try to fix any moisture issues and sheet rock isn’t too expensive… Most likely it will be a longer project that I slowly work on the next couple months if I decide to go further than I already have.