Questions for using metal roof panels for under deck drainage
Based on reading old messages, I'm looking to try Al the Deckman's method of using metal roof panels on the underside of deck to keep my patio area somewhat dry. Basically, he says to attach extra joist boards on a slope and then create a 2x4 frame perpendicular for mounting the metal sheets to.
I have a few questions, can Al or someone else help me:
1. Should I use pressure treated lumber for the extra joist boards and 2x4's? I would assume yes?
2. My existing joists are 16 inches on center. Should the extra sloped joist board be attached to every existing joist or can I skip and attach one on every other joist?
3. Would it be better to nail or screw the extra joist boards and 2x4 framing?
4. Should the 2x4 framing be 16 or 24 inches on center?
5. The metal panels will span 15 feet. Should I get panels made for that entire length, or should I split it in half and overlap the seams? Even with extra help, it would seem hard to screw on a 15-foot long panel upside down?
6. How should the metal panels be screwed on, through the humps or on the flat part of the panel?
Thanks for any help on answering my questions.