Yes, for a couple of reasons:
- As a shed or garage, it was permitted to be below flood levels so long as it had flood vents in the bottom. As such, it could only be used for storage and parking. Converting this storage space to habitable space (occupied room, office, workshop etc) is a change of use, which requires elevation.
- This conversion will most likely exceed 50% of the building’s value, resulting in a Substantial Improvement, which requires elevation.