Framing & StructuralQuestion 296 of 700
On a wood structural panel span-rating stamp such as 24/16, what does the second number (16) represent?
a.The maximum roof rafter spacing the panel may bridge
b.The maximum floor-joist spacing (inches) over which the panel may serve as subfloor
c.The panel thickness in sixteenths of an inch
d.The minimum nail spacing at panel edges
Explanation
On a span-rated panel the two numbers are roof-support spacing / floor-support spacing. The 16 means the panel is rated as subfloor over joists up to 16 inches on center. The 24 is the roof rafter spacing, not the second number. Thickness is stamped separately, and edge nailing is set by the fastening schedule.
Law Reference: 2025 CA Residential Code §R503.2.1Practice all 700 questions free — no signup required.
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