Reinforcing South facing wall sheathing on cabin
I have plywood exterior walls with pinetar/lineseed oil for protection in my cabin. I have vertical boards covering the gaps where the plywood meet. Interior I have typical pink insulation and drywall.
I want to reinforce the south facing wall to help with heat in the summer and combat the elements / uv degradation and heat. I have a ton of extra roofing metal. Im considering putting the metal roofing on this south facing exterior wall leaving a 1" air gap between the metal roofing and the plywood wall.
Googles saying "Putting a metal exterior on a south-facing wall can cause massive heat gain" but I am not sure how exactly, there will be an air gap and the metal roofing is what will be heating up, not the plywood walls.
Would this be an effective solution? Or is there a better idea?