Our patio roof (approx 36' x 12') is the floor for the second floor bedrooms, and was always cold in winter. After pulling down several 1/4 sheets of plywood I found out why; the only insulation was in the joists, which left a good 7" of air space behind, along with being completely open to the rest of the house, resulting in uncontrolled air movement. I finally decided to remedy and have the entire area spray foamed with 5" of open cell.
I next put of a layer of vapor barrior, as open cell is porus, and I didn't feel like spraying it with paint to seal it.
Hung the plywood back up and, after looking at all the bad seams and broken corners (house is 25 years old, and plywood was original to the build), I decided to apply the same treatment to it I did in our living room. I bought about 130 6' fence pickets and started nailing them up. After the first course, I wasn't happy with how crooked it looked, and let it sit overnight to think about it.
Next morning I started taking them down when water started spraying everywhere; I had put a brad right through the toilet supply line. I had to cut a 9" square back out of the wood and not further damage the line. After finally getting the cuts done and wood removed, I found the nail had barely nicked the side of the pipe . Nedless to say I was not very happy at that point, having to go through all that just for a pin prick. Got a Shark Bite and fixed the issue.
Backing off for another night, I started the process all over again come morning, this time being more careful and with better results. I resealed the hole with some thick yard trash bags sealed with vapor wrap tape and started by laying out a couple of chalk lines. It took a couple of days, but finally got the boards hung. I cut the dog ears off and hung each board.
After reinstalling trim, I also hung a couple of new, wicker look ceiling fans with LED bulbs.
Not cleaned up at this point; I'll get some finished pics up later.
For now it's done for the winter. Come spring we will be screening it in.