I need to clear span 40' for a second story floor and want to do this with metal trusses.
Wooden floor trusses max out at 36', and require 12" OC spacing at that length. Not only is that too short, but it's a bunch of material to ship/handle.
My intent is to make (4) trusses that each support (18) 2x10's, with the outside wall holding the loose ends via a ledger of some kind.
My current design idea uses a 2x4x.125" top cord, (2) 2x2x.125" angle bottom cords, welded to 1.75x1.75x.125" square tubing diagonal webs, with 3x3x.125" vertical webs @ 24" spacing.
I'd then laminate the top cord with a 2x4 to provide a nailing flange for the subfloor.
Two questions: Would this be sufficient @ 18" web depth? If not, would it be @ 24"?
If not, what would I need to change?