Clearance between header and ground ???? 1971 A Body

Rafter ties refers to the metal straps that tie the studs to the rafters. Everything should be tied together so that nothing can get ripped away during high winds. At least they call them rafters ties where I live?
https://www.lowes.com/pd/USP-6-1-2-...MIl5m4moPP3QIVBgtpCh15LQXUEAQYAyABEgLHtvD_BwE
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don't know codes where he lives, but as you can see, those go on the outside before sheathing. but, you are correct, you can add 'hurricane' clips from the inside if needed. don't know how the building is held to the foundation/footing, but if it's just sitting on a pad the whole building will roll away (intact) with a good enough wind. need better pictures to see what is there.