Re-nailed Deck With Mixed Fasteners
An inspector is evaluating a 1999 single-family home with a 5:12 gable roof and 7/16-inch OSB decking. In the attic, the original fasteners appear to be 8d common nails at 6 inches along panel edges and 12 inches in the field. A 2019 re-roof added 8d ring-shank nails at 6 inches by 6 inches over roughly 60 percent of the accessible attic, but two bays are blocked by HVAC equipment and a finished ceiling. The homeowner provides a contractor affidavit stating that the entire deck was re-nailed with 8d ring-shank nails at 6/6 and that all panels were replaced. No permit records are available. The visible enhanced nails are in the correct pattern, but several panels still show only the original 8d common nails, and one ring-shank nail misses the truss. The inspection form must choose a roof deck attachment rating.
1. What roof deck attachment rating is supportable, and why?
Read the worked answer
Supported rating on the present evidence: 8d common at 6/12, not 8d ring-shank at 6/6. The rating follows the weakest verified fastening pattern in the roof deck, not the best-looking bay and not an average. Visible panels with only original 8d common nails at 6/12 establish that pattern. The 2019 ring-shank nails at 6/6 are an upgrade only where the pattern is complete and verified. The contractor affidavit is evidence, but it conflicts with visible original nails and does not resolve the blocked bays. The single misplaced ring-shank nail is a defect to photograph and note; by itself it does not prove the whole deck is 6/12, but it weakens the claim of a consistent 6/6 installation. If the insurer accepts the affidavit and it clearly covers every bay, the inspector may report the enhanced rating with a written limitation; otherwise report 8d common at 6/12 and explain the partial upgrade.
2. How should the missed nail and blocked bays be documented?
Read the worked answer
Document the blocked bays as inaccessible, not verified. Photograph the obstruction, the access opening, and the nearest visible deck area. For the missed nail, take a context photo and a close-up with a tape measure; note the location and whether the nail misses the truss or splits the panel. Do not remove HVAC equipment or cut a finished ceiling. If the affidavit says all bays were re-nailed, attach it and state exactly what it covers and what remains unverified. The report should separate observed conditions from claimed conditions so a reviewer can see why the selected rating is the weakest verified pattern.
3. What photographs are needed to support the final rating?
Read the worked answer
Provide an attic overview showing access and deck; a panel thickness stamp; a close-up of the original nail head and shank; a close-up of the ring-shank nail; a tape measure showing 6-inch edge spacing and 12-inch field spacing; and a tape measure showing any 6/6 pattern. Also photograph the blocked bays, the roof covering, and any permit sticker. If an affidavit is used, photograph or scan it. The photo set must let a reviewer independently see the weakest verified pattern rather than infer it from a summary.