Nail Spacing

[Robert_R.Sheppard]

@tallore

I need some clarification. When I google nail size charts the 6d and 8d nail the lengths are often the same length. But the listed diameter is always the same. 6d diameter .113 of an inch and 8d is .131 of an inch. Should I be using a nail gauge to determine the “size” of nail for the 1802. Example : a nail thru the roof deck appears to be a total of 2 and 3/8 inches. 7/64 is smaller than .113 of an inch using my math… With these numbers a 6d would be tight or not fit in the 7/64. And a 8d nail would fit in the 9/64 hole. An agent tells me 2 3/8 inch nail is an 8d. The nail was loose in the 7/64. So my question is what is correct way to determine nail “size” using legth or diameter? thank you in advance

The qualification for an 8D nails are listed in the 2010 Florida Building Code, Existing Building: 611.7.1.2 Supplemental fasteners as required by Table 611.7.1.2 shall be 8d ring shank nails with round heads and the following minimum dimensions:

1. 0.113-inch nominal shank diameter.
2. Ring diameter a minimum of 0.012-inch greater than shank diameter.
3. 16 to 20 rings per inch.
4. A minimum 0.280-inch full round head diameter.
5. Ring shank to extend a minimum of 11/2 inches from the tip of the nail.
6. Minimum 2-1/4 inch nail length.
   It’s important to remember that 8D gun nails are not 2 1/2" long, they are 2 3/8" long. Common nails are required to be 2 1/2" long to qualify as 8D nails. But, determining nail length by measuring the exposed nail at the underside decking is very inaccurate…you have no way of knowing if that nail is over-driven or under-driven through the deck. A properly driven 8D ring-shank gun nail will be exposed at the underside roof deck(19/32") about roughly 1 3/4"…not 2". The nail is required to be level with the surface of the decking, anything more and it is over-driven…