Roof deck attachment: 6d vs. 8d nails on the wind mitigation form

OIR-B1-1699 wind premium credits for existing construction: roof covering not equivalent to the Florida Building Code, no secondary water resistance, no opening protection, terrain B, 2% deductible. Rounded to whole numbers. OIR lists this form as effective October 2006 with updates pending.

What question 5 asks

The form asks: "What is the WEAKEST form of roof deck attachment?" Citizens' Wind Loss Mitigation Guide says roof deck attachment should be applied based on the weakest attachment the inspector indicates. The answers are A, B and C for nailed or fastened sheathing, D for a reinforced concrete roof deck, E for spray foam, F for Other, G for unknown or unidentified, and H for no attic access.

Florida Statutes s. 627.0629(1) says residential property rate filings must include discounts, credits or other rate differentials for construction techniques shown to reduce windstorm loss, and it lists wind uplift prevention and roof strength among them.

A. Staples or 6d nails

Answer A is plywood or oriented strand board (OSB) sheathing at least 7/16" thick, attached to trusses or rafters spaced at most 24" on center, by staples or 6d nails spaced 6" along the edge and 12" in the field. Answer A also covers batten decking supporting wood shakes or wood shingles, with trusses or rafters at most 24" apart. A third option is any system of screws, nails, adhesives or other deck fastening with an equivalent mean ultimate uplift resistance of at least 55 psf, but less than B or C require.

The form adds a note: if the nailing or rafter spacing is greater than specified, or the decking is thinner than specified, the inspector selects F, Other. Citizens' guide says Rev. 04/26 added uplift thresholds to answer A, which had none before, and added that clarification on when to select Other.

B. 8d nails at 12" in the field

Answer B is the same 7/16" plywood or OSB on trusses or rafters at most 24" on center, attached by 8d common nails spaced a maximum of 12" in the field. It also covers any fastening system shown to have equal or greater resistance than that, or a mean ultimate uplift resistance of at least 103 psf.

C. 8d nails at 6" in the field

Answer C is 7/16" plywood or OSB attached by 8d common nails spaced a maximum of 6" in the field, again with trusses or rafters at most 24" on center. Dimensional lumber or tongue-and-groove decking also qualifies, with at least 2 nails per board, or 1 nail per board if each board is 6" wide or less. Any fastening system shown to equal 8d nails at 6" in the field, or with a mean ultimate uplift resistance of at least 182 psf, also counts.

OIR's notice to policyholders (OIR-B1-1655) describes the three nailing levels under "How Your Roof is Attached": a 2" nail spaced 6" from the edge of the plywood and 12" in the field, a 2 1/2" nail at the same spacing, and a 2 1/2" nail spaced 6" from the edge and 6" in the field. OIR-B1-1699 labels its three deck rows as 6d @ 6"/12", 8d @ 6"/12" and 8d @ 6"/6" or dimensional lumber deck.

D. Reinforced concrete roof deck

OIR-B1-1655 lists a reinforced concrete roof deck as its own feature and says that if it is installed on your home, you "most likely will not qualify for any other discount." In OIR-B1-1699, a reinforced concrete roof deck in terrain B shows 82% with no opening protection and 84% with basic or hurricane protection. Citizens' guide enters answer D as Reinforced Concrete Roof Deck, and for secondary water resistance it says to check its Wind Loss Mitigation Help Chart to decide between SWR and Not Applicable, which varies by year built and terrain.

E. Spray foam, new on Rev. 04/26

Answer E is spray foam products with an uplift resistance of 110 psf (FOS 1.5), and the form says the foam must be installed along rafter deck intersections, all panel joints and similar areas. Citizens' guide lists spray foam as an option added on Rev. 04/26 and enters it in its systems as Level B. Spray foam installed the same way is also one of the qualifying methods for a sealed roof deck under question 8, where the inspector can check a box if the entire underside of the roof deck is covered.

F, G and H: Other, unknown and no attic access

Citizens' guide enters answers F (Other), G (Unknown or unidentified) and H (No attic access) as "Unknown or Unidentified" in its systems. Citizens' page on wind inspections says attic access is required to verify certain mitigation features and asks you to make sure your attic is accessible before the inspector arrives. It says that if the inspector cannot access your attic, you may not be eligible for discounts for roof-to-wall attachment, roof-deck attachment and secondary water-resistance features.

Photos and FORTIFIED certificates

The form says at least one photograph or document must accompany it to validate each attribute marked in questions 2 through 9, and any documentation used to validate an attribute must be attached. Citizens' guide says underwriting may ask for additional photographs or other documentation.

A FORTIFIED Home Roof, Silver or Gold certificate may be used to validate questions 4 through 6, 8 and 9, according to the form. For roof deck attachment, Citizens' guide enters a current FORTIFIED Home Roof, Silver or Gold certificate as Level C. It describes Fortified Roof as construction standards that ensure the roof stays attached and resists water entry during high-wind events.

What deck nailing can be worth

OIR describes OIR-B1-1699 as displaying the range of wind premium credits for existing construction on single family residences. In the rows at the top, moving from deck A to deck B makes the biggest difference when the roof is not a hip and has clips: 35% versus 58%. Deck C shows the same or nearly the same credit as deck B in those rows. OIR-B1-1655 says discounts "are not calculated cumulatively" and apply only to the hurricane-wind portion of your policy. OIR's resources page says it continues to evaluate OIR-B1-1699 for updates, so ask your insurer for its current figures. See how much a wind mitigation inspection saves, roof-to-wall attachment and roof shape.

Renailing the deck when you reroof

Florida Statutes s. 553.844(2)(b)4. directs the Florida Building Commission to adopt, for site-built, single-family homes built before the Florida Building Code, techniques for strengthening or correcting roof-decking attachments and fasteners during reroofing. Section 553.844(3)(a) says the rules must require that a roof replacement on a site-built, single-family home incorporate that technique, along with secondary water barriers. See new roof: Florida reroof rules.

Florida Statutes s. 215.5586(2)(e) says that when recommended by an initial hurricane mitigation inspection, My Safe Florida Home grants may be used for roof improvements that include improving the strength of roof-deck attachments. Section 215.5586(2)(f) says improvements must be identified by the final hurricane mitigation inspection to receive grant funds, and s. 215.5586(2)(d) says the work must have all required local permits and inspections and be done by properly licensed contractors. See My Safe Florida Home vs. a private inspection.

Before your inspection

• Clear the attic access: Citizens says attic access is required to verify roof-deck attachment, and that your representative should know where to find it if you can't attend.
• Gather paperwork: Citizens lists receipts with product specifications, work orders, invoices and roofing permits as acceptable documentation, and our guide to finding your roof permits shows where to look.
• Give documents first: Citizens asks you to give the inspector copies of any mitigation documents before the inspection begins.
• Compare prices: our Palm Beach County prices page lists wind mitigation prices published by inspectors, and city pages such as West Palm Beach and Boca Raton list inspectors by area.

FAQ

What is the difference between 6d and 8d nails on the wind mitigation form?

On the OIR-B1-1802, answer A is staples or 6d nails at 6" on the edges and 12" in the field. Answers B and C use 8d common nails, at a maximum of 12" or 6" in the field. OIR's policyholder notice, OIR-B1-1655, describes deck nailing levels using a 2" nail and a 2 1/2" nail.

Does roof deck attachment lower home insurance in Florida?

It can lower the hurricane-wind part of the premium. Florida Statutes s. 627.0629(1) requires rate filings to include discounts for construction techniques that include wind uplift prevention and roof strength. In OIR's OIR-B1-1699 table, a non-hip roof with clips, no secondary water resistance and no opening protection shows 35% with deck A and 58% with deck B.

How does the inspector check roof deck nailing?

Citizens says attic access is required to verify roof-deck attachment, and the form has an answer H for no attic access. Citizens' Wind Loss Mitigation Guide enters no attic access, Other and unknown as Unknown or Unidentified.

Does spray foam in the attic count for roof deck attachment?

Rev. 04/26 added answer E for spray foam products with an uplift resistance of 110 psf (FOS 1.5), installed along rafter deck intersections and all panel joints. Citizens' Wind Loss Mitigation Guide enters answer E as Level B.

Do I have to renail the roof deck when I replace my roof?

Florida Statutes s. 553.844(3)(a) says the rules for site-built, single-family homes must require a roof replacement to include strengthening or correcting roof-decking attachments and fasteners, along with a secondary water barrier.

Sources

• Florida OIR, Uniform Mitigation Verification Inspection Form OIR-B1-1802 (Rev. 04/26), questions 5, 6 and 8 and photo requirements: floir.gov (PDF) (checked Oct 29, 2026)
• Citizens Wind Loss Mitigation Guide (Rev. 04/26), sections 5 and 8 and the documentation and Fortified Home requirements: PDF (checked Oct 29, 2026)
• Citizens Property Insurance, Your Wind Inspection (attic access, documents): citizensfla.com (checked Oct 29, 2026)
• Florida OIR, Windstorm Mitigation Discounts; Single Family Residences, OIR-B1-1699: floir.gov (XLS) (checked Oct 29, 2026)
• Florida OIR, Notice of Premium Discounts for Hurricane Loss Mitigation, OIR-B1-1655 (Rev. 02/10): floir.gov (PDF) (checked Oct 29, 2026)
• Florida OIR, Wind Mitigation Resources (form list and dates): floir.gov (checked Oct 29, 2026)
• Florida Statutes s. 627.0629 (2026), residential property insurance; rate filings: leg.state.fl.us (checked Oct 29, 2026)
• Florida Statutes s. 553.844 (2026), windstorm loss mitigation; requirements for roofs and opening protection: leg.state.fl.us (checked Oct 29, 2026)
• Florida Statutes s. 215.5586 (2026), My Safe Florida Home Program, subsection (2): leg.state.fl.us (checked Oct 29, 2026)