How do I know if I need a building permit for a structure located in the unincorporated area?

All new structures, decks, and roofs within unincorporated Johnson County require a building permit.

A permit is required to enlarge, alter, repair, move or demolish a building or structure.

A permit is also required to repair, remove, convert, or replace electrical, gas, mechanical, or plumbing.

The department website provides a list of "work exempt from permits", categorized by Residential, Commercial, Electrical, etc.