My home 1884 has a porch on the second floor directly over the 1st floor one. It looks like a previous owner tried to turn it into a room. Windows all around and drywall. The roof on the forst floor porch has what looks like drywall.

In winter it's absolute freezing. I suspect that the space between the porchs is not insulated. I was thinking of drilling an exploritory hole and see what's there. If it's empty as I suspect. I was going to remove pieces of the porch ceiling and use some kind of rolled insulation in there. Does this sound reasonable or am I way out there.

Would the ceiling between the 1st and 2nd porchs be drywall? I don't think that drywall would last in such an exposed place, or is there some other drywall like boards that are use for porch ceilings?