In areas with high winds, the maximum nail spacing for underlayment is?

• A. 24 inches
• B. 16 inches
• C. 36 inches
• D. 30 inches

Answer: (C)

In high-wind zones, underlayment must be secured tightly enough to resist uplift, so there’s a limit to how far apart fasteners can be placed. The largest spacing allowed is 36 inches, meaning you can place nails no farther than three feet apart along the sheet. You may use closer spacing if you want extra hold, but you cannot exceed this 36-inch maximum. This balance helps ensure wind resistance without making installation impractical. Spacings like 24 or 16 inches are just more conservative options, and 30 inches is within the limit but not the maximum.