Research by DoINeedAPermit Research Team · Updated May 2026
The Short Answer
Any attached deck in Florence requires a permit, regardless of size. Even small decks need ledger flashing detail, footing inspection, and framing sign-off. Freestanding ground-level decks under 200 sq ft and 30 inches high may be exempt.
Florence's Building Department enforces the International Residential Code (IRC) R507 deck standards, and the city's 12-inch frost depth is shallower than many inland SC regions, which affects footing design and cost. Unlike some neighboring jurisdictions that allow owner-builder exemptions for small decks under certain square footage, Florence requires a permit application and plan review for any deck attached to a house — the attachment to the structure triggers the permit threshold. What sets Florence apart is its jurisdiction over both City limits and unincorporated areas that may have different timelines; if your property is in the city proper, you'll file with Florence Building Department downtown, but if you're in the extraterritorial jurisdiction or outside city limits, you may file with Florence County Building Services instead. The sandy coastal soil composition (especially near the floodplain) means footings must account for soil bearing capacity, and if your deck is within or near a floodplain zone, additional elevation or flood-resistant connection details may be required. Plan on 2–3 weeks for review and a $200–$400 permit fee based on deck valuation.

What happens if you skip the permit (and you needed one)

Florence, SC attached deck permits — the key details

Florence Building Department applies IRC R507 (Decks) as the foundation of its requirements. Any deck attached to a house — meaning the deck band board or ledger is bolted or nailed to the house rim joist — requires a permit application, building permit, and plan review before work starts. The IRC R507.9 ledger attachment detail is the single most-cited issue in Florence deck rejections: your ledger must be flashed with L-channel or Z-flashing that diverts water away from the house rim, bolted to the rim joist with ½-inch bolts at 16 inches on center, and detailed on your permit drawings. Frost depth in Florence is 12 inches, so all footings must extend below that depth (typically 18 inches in practice). Post-to-beam connections must use approved lateral load devices (Simpson Strong-Tie DTT or equivalent) where the deck band board attaches to the ledger, resisting the horizontal and uplift forces that occur when the house and deck flex independently. Ground-level decks (less than 30 inches above finished grade) that are freestanding — not attached to the house — may be exempt if they're under 200 sq ft, but the moment you tie a ledger to the house, you've crossed the permit threshold.

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City of Florence Building Department
Contact city hall, Florence, SC
Phone: Search 'Florence SC building permit phone' to confirm
Typical: Mon-Fri 8 AM - 5 PM (verify locally)
Disclaimer: This guide is based on research conducted in May 2026 using publicly available sources. Always verify current deck (attached to house) permit requirements with the City of Florence Building Department before starting your project.