Do I need a permit for deck construction or replacement in Lexington County (Unincorporated)?

Most likely yes. Deck construction or replacement usually requires a permit in South Carolina. Confirm the specifics with Lexington County (Unincorporated).

South Carolina's statewide code adoption does not include the codes' administrative chapters (S.C. Code Section 6-9-50 and the Building Codes Council's adoption notice). The list of work exempt from a permit is set by each city or county ordinance, so ask your local building office before assuming an exemption applies. South Carolina amended guard Section R312.1.1 of its residential code: guards are required on open sides of decks more than 30 inches above the floor or grade below, and also where the ground slopes down steeper than 3 in 12 within 36 inches of the open edge. Under S.C. Code Section 40-59-20, a residential builder license is needed for residential work costing over 5,000 dollars. An owner building for their own use can apply under the Section 40-59-260 exemption by signing the permit application personally. 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.