I agree that a structural engineer would be an over-kill. I would recommend repairs by a framing contractor.

That peel and stick stuff is pretty good and would certainly assist with additional waterproofing and then re-covering. Since these are vaulted ceilings, that's probably the best way to approach it in lieu of trying to come up from the inside.

rr

__________________
"If con is the opposite of pro, is Congress the opposite of progress?"
Richard Rushing, HCRI
Duncanville, Tx.