Slide 59 of 67
WHY ARE COMMON NAILS IMPORTANT?
- Common nails have greater stiffness
- Common nails and box nails have almost identical head sizes and so wood structural panel sheathing fastened with these nails will reach the same ultimate strength.
- However, common nails have less slip than box nails due to their increased shank diameter giving them greater stiffness.
- Since shear walls must provide both strength and stiffness, the use of box, cooler or sinker nails will reduce the performance of the shear wall.
- Performance Losses for Nail Substitutions - Table 5
- Use 6d nail as example
- Note greater shank diameter of common nail
- Note that because of the greater diameter, the minimum spacing is greater for common nails compared to box nails
- Note that common nails have a greater allowable load value (based on stiffness) by about 20% than box nails
- For sheathing, four common nails provide the same stiffness as five box or cooler nails
- What happens if box or cooler nails are used for sheathing?
- You will need to use 25% more nails to make up the difference.
- However, additional nailing must follow the requirements for minimum spacing and framing member sizes.
- For example:
- When additional nailing creates spacing of 6d or 8d at 2 inches on center or 10d at 3 inches on center, 3 inch nominal width framing members are required at all adjoining panel edges.
- When the original common nail spacing was equal or less than 6d at 2 inches, 8d at 2½ inches or 10d at 3 inches, additional nails cannot be used because of minimum spacing requirements.
- In these cases, additional sheathing must be provided and is usually installed on the other side of the same wall.
- Remember that it is always easier in the long run to do it right the first time.