Do I need a permit for deck construction or replacement in Mount Lebanon?

Most likely yes. Deck construction or replacement usually requires a permit in Pennsylvania. Confirm the specifics with Mount Lebanon.

Under 34 Pa. Code Section 403.62(c)(8), an uncovered deck whose floor is no more than 30 inches above grade needs no UCC permit. Pennsylvania sets no size limit and no attached or freestanding test for that exemption. A deck with its floor more than 30 inches above grade, or any deck with a roof over it, is outside the exemption and needs a permit. The exemption applies only if the work does not violate a law or ordinance, so local zoning setbacks still apply. The UCC is administered locally. Your municipality enforces it through its own code office or a certified third-party agency, and in a municipality that has opted out, the owner or contractor hires a certified third-party agency for residential work. Confirm who covers your address. 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.