A structural permit is required for a tear-off and reroof. The permit is considered miscellaneous activity (also called a non-review permit) and no plans are required unless there is a change in type of roofing (i.e., changing from asphalt shingles to clay tile or slate).
A permit is not required to add an additional layer of shingles to a residential structure, provided that the work is done by the property owner or contract purchaser using the home for their own occupancy. In Marion County, you may apply two (2) layers of shingles before a tear-off and reroof is required.