Originally Posted by CraigFL
It does more than that! It's the main reason the roof doesn't fall flat onto the lower part of the building and the reason the tops of the walls don't spread apart. They are in tension from the roof load and help carry the vertical load down through the walls.
Yeah, of course they do! I was over simplifying to make my point that the bottom chord, as is, was not engineered for the live load of a living space.