CSLB General Building (B)Framing and CarpentryMedium
A framing crew is installing 23/32-inch plywood subfloor panels over floor joists using 8d common nails per standard prescriptive nailing requirements. What nailing schedule should they follow?
- A8 inches on center at edges and field, uniformly
- B6 inches on center at edges, 12 inches on center in the field
- C12 inches on center at edges, 16 inches on center in the field
- D4 inches on center at edges, 8 inches on center in the field
Show answer & explanationAnswer & explanation
Correct answer: B. 6 inches on center at edges, 12 inches on center in the field
The standard prescriptive nailing schedule for plywood subfloor panels attached with 8d common nails is 6 inches on center along panel edges and 12 inches on center at intermediate (field) supports. This spacing ensures adequate diaphragm and structural performance.
Why the other options are wrong
- A. Uniform 8-inch spacing does not match the differentiated edge/field pattern required by code.
- C. This spacing is too wide and does not meet standard prescriptive requirements.
- D. This tighter spacing is used for higher-demand diaphragms, not standard subfloor nailing.
Subfloor Nailing Schedule
Wood structural panel subfloors are typically fastened with 8d common nails spaced 6 inches on center at panel edges and 12 inches on center at intermediate supports.
- 6 in o.c. at edges, 12 in o.c. in field is standard
- 8d common nails are typical for standard subfloor thickness
- Tighter spacing may be required for diaphragm shear demands
Memory trick: 'Six at the edge, twelve in the middle keeps the floor from a diddle.'