Hi there!
I'm in the process of replacing the panel on my garage. The boards are from the early 70s and are rotten at the bottom but completely fine higher up.
Today I discovered when taking them down that there is no air gap between the bottom board and the asphalt board. Naturally, there's a vertical air gap between each bottom board! =)
Do I need to change the construction and create some form of air gap now that I'm putting up new boards, or can I just nail the new panel up exactly as the old one was? After all, it's worked pretty well for 40 years...
I should add that the asphalt board looks great, hardly any holes or signs of moisture at all.
Behind the asphalt board, there is insulation, plastic, and then drywall. The garage is unheated but consistently stays above freezing even in winter.
Grateful for any input! =)