PM me.
I was just going to use it to see if I can muscle a full length 20 up there, I used the PT boards as floor joists… I have a few leftover.
I’d use regular lumber if only for the fact that it’s lighter and since I don’t have to use expensive as all hell composite/deck screws.
Are there are spray foam rental places around here?
Since all my studs are 18-19"OC, it’s a pita to insulate with regular glass.
frankly it looks like those 2x4 members are almost entirely in tension due to the roof structure…they should hold up GWB loads without a problem, although if you put storage above i would most certainly sister them up with 2x6’s or more…the biggest problem with old rough sawn lumber is that it is usually dry as hell and loses a lot of its shear strength due to twisting and various nailing and notching over time…
if you really want o know, there are plenty of dimensional lumber charts out there to give you a rough idea of the loading you are dealing with