When you replace your roof in Florida, the building code requires the roof deck to be re-nailed to current wind standards. But sometimes the deck itself is too damaged to just re-nail — it needs full replacement. Here's how to tell the difference and what it means for your budget.
Under the Florida Building Code 8th Edition (2023), when a roof covering is removed and replaced on a building with a wood roof deck, the deck must be attached to meet current wind resistance requirements for new construction. This means:
8d ring-shank nails (2-3/8" x 0.113") are required — smooth shank nails do not comply. Perimeter zone fastening at 6" on center. Field area fastening at 6" o.c. in HVHZ (Broward, Miami-Dade) or 12" o.c. minimum elsewhere. CRWP's standard is 6"/6" everywhere for maximum wind resistance.
Code Reference: FBC 706.7.1 — "When a roof covering is removed and replaced on a structure with a wood roof deck, the roof deck shall be attached in accordance with the wind resistance requirements of the FBC for new construction."
If your existing plywood or OSB deck is solid, dry, and structurally sound, re-nailing is all that's needed. The contractor removes the old roof covering, inspects the deck for rot, delamination, or soft spots, and then re-nails the entire deck with 8d ring-shank nails at the required spacing. This is the standard process on most re-roofs and adds minimal cost to the project.
Sometimes the deck is too far gone for re-nailing. Here are the conditions that trigger full or partial deck replacement:
Florida's climate is particularly harsh on wood roof decks. The primary enemies are: moisture intrusion from failed underlayment or flashing, which causes plywood delamination and rot. Repeated tropical storms and hurricanes that stress fastener connections over time. Attic condensation from poor ventilation, which degrades the underside of the deck. Termite damage in South Florida's subtropical climate.
Cost Tip: Deck replacement adds up fast. A 30 SQ roof with 20% deck damage might need 15-20 sheets replaced — adding a significant amount to the project. This is why a thorough inspection before signing the contract is critical.
Under FBC 706.7.2, any full roof replacement with a wood deck requires a secondary water barrier. This is achieved with self-adhered underlayment (peel-and-stick) installed directly to the clean deck. The SA underlayment provides waterproof protection even if the primary roof covering is blown off in a storm. CRWP uses Polyglass TU Max or TU Plus as the standard secondary water barrier on all steep-slope re-roofs.
If your home was built before the Florida Building Code (pre-2002) and is in a wind-borne debris region (all of South Florida), has a wood deck, and the insured value is $300,000 or more, FBC 706.8 may require a roof-to-wall connection retrofit. The good news: the retrofit is capped at 15% of the re-roof contract amount. If the full retrofit would cost more than 15% of your re-roof price, the code exception applies and no retrofit is required. This is the most common outcome on older South Florida homes.