Do I need a permit for deck construction or replacement in Unincorporated Bullitt County?

Most likely yes. Deck construction or replacement usually requires a permit in Kentucky. Confirm the specifics with Unincorporated Bullitt County.

Kentucky does not require a building permit or inspection for a single-family dwelling unless the local government has passed an ordinance creating a residential inspection program (KRS 198B.060 and 815 KAR 7:125, Section 2(2)(a)), so the first question is whether the city or county covering the address has one. Where a local program exists, the Kentucky Residential Code (Section R105.2) exempts only decks of 200 square feet or less that are no more than 30 inches above grade at any point, are not attached to the house, and do not serve the required exit door; other decks need a building permit. Deck ledgers may not be supported on stone or masonry veneer unless specifically designed by a design professional or attached with an approved listed fastening method, and girders may not be supported on a ledger or band joist (KRC Section R507.2.2). Deck lights, fans, or outlets need a state-required electrical permit and inspection even where no local building program exists (KRS 227.480). This deck is attached to the house or will have a roof. Where a small deck exemption exists at all, it covers only small, low, freestanding decks that do not serve the home's required exit door, so an attached deck falls outside it. A ledger bolted to the house is the most common point of deck failure, which is why departments inspect the footings, framing and ledger connection before the decking goes on. Adding a roof makes the deck a covered structure that is reviewed like a patio cover or addition, including roof framing and, in high wind areas, uplift connections.