I built a porch on my house last year and made a big mistake. The framing is treated wood and the roof is metal. In the summer, that metal roof turns the porch into an oven. I can't spend time out there at all....it's just too hot! I'd love to insulate it but I am afraid of creating a moisture problem between the metal and whatever I use for insulation. Any suggestions? Thought about spray foam insualtion right against the metal. Might be pretty expensive though. also though about installing a ceiling on the bottom of the treated roof rafters, but this would create a dead air space between the ceiling and the metal roof.