What type of home improvements requires a building permit?

A building permit is needed for an addition, porches, porch roofs, decks, swimming pools (Above-Ground and In-Ground, greater than 24” deep), spas, hot tubs, accessory structures 200 square feet and over, structural alterations to existing structures, removal or change of any required means of egress, fences over six (6) feet high, retaining walls over four (4) feet high, sidewalks more than 30 inches above adjacent grade, driveways more than 30 inches above adjacent grade, and demolition of existing structures.