What purpose do the wind girts on a metal building serve?
The wind girts on a metal building support the metal siding. In technical terms, they transfer the wind load from the siding to the vertical supports. The wind girts are needed because, even though our metal siding is very strong and durable, it is not rigid enough to span the entire vertical height of a building without buckling in high winds or in the event of an impact. The metal panels need some back-up.
The wind girts are useful for other things, too. They can support insulation and interior finishes, and they help resist horizontal wind forces from the adjacent sides of the building as well as wind that hits them head-on.