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You shouldn't install felt. Installing tyvek won't hurt but since the purpose of Tyvek is to stop air infiltration it won't be very effective only in one small area
The sheathing was taped with duct tape and it has deteriorated. I'm thinking of simply filling voids with spray foam. Ideas?
voids between the sheets?
Then expanding foam is a good choice. You'll want to trim off the excess before it sets up for too long. It's easier when it hasn't cured for more than a day