Wind mitigation question

On several wind mitigation inspections I have found that the nails holding the roof deck measure 1 7/8" as they protrude through the decking. If you factor in the 7/16 thickness of the roof deck, that means that they are 2 5/16" long (or maybe 2 1/4" if it is overdriven). In the Bill York class, he said that an 8d nail was 2 3/8" to 2 1/2" long.

The nail is obviously longer than 2" as would be a standard 6d nail. Would you call this an 8d nail?

The nails your seeing are “gun” nails and even though they may be short a fraction are still considered 8d nails. Then there are some that claim the d used to denote penny size is actually a reference to diameter not length.

Looks like an overdriven 8d nail, i would say… You got 2 inches right there and it looks like the nail head isnt close to being exposed. I would call it an 8d…

A lot of times a missed nail in OSB is driven half way through the board since there is no resistance. notice the blow out on the bottom side. Tough call —

Not all 8d nails are created equal. Got Nails?:stuck_out_tongue:

Deformed shank nails have a great holding power than smooth. Sometimes twice the uplift.

This should count as continuous education.

Dennis I agree --this nail has obviously missed the truss tc and pushed thru the OSB, the bottom of the head is almost visable. My call would be 6 penny. The nail size is measure from the bottom of the head to the tip.

http://www.engineersedge.com/nail_size_chart.htm

Happy Friday !:slight_smile:

I had been calling these 6d nails based on the fact that they did not meet what I normally would consider the length of an 8d nail but I have been seeing them in homes that had been renailed according to code requirements. Which requires 8d nails.

I have seen them also where they are sticking out the side of the truss but chose this photo because it showed the whole nail so I do not think they are all overdriven that much into the OSB.

It kept bugging me because the nail is obviously longer than a 6d nail. I finally found this on a page from one of the jurisdictions in Florida and it describes an 8d nail as being only 2 1/4" long. (I know it is not related to wind mitigation inspections but is related to roofing in general). See http://www.palmettobay-fl.gov/pdfs/Roof%20Mitigation%20Form.pdf.

This made me rethink things and I am leaning toward calling these 8d nails. I just wanted other opinions to see if I was looking at thing correctly. I want to make sure I am doing the inspections correctly and at the same time, I want to make sure I give credits where they are due.

Nice post

I wonder if the OIR and Mr. York are going to rethink the minimum length of what is considered an 8d nail because homes being built under the latest residential code FBRC 2007 may not meet the current definition of minimum length.
Chapter 8 code article 803.2.3.1 Sheathing Fasteners
Wood structural panel sheathing shall be fastened to roof framing with 8d ring-shank nails at 6" o.c. at edges and 6" o.c. at intermediate framing. ring-shank nails shall have the following dimensions.

  1. 1.113" nominal shank diameter
    2)ring diameter of 1.012 over shank diameter
  2. 16 to 20 rings per inch
  3. 0.280 inch full round head
  4. 2 inch nail diameter
    Obviouly the superior holding strength of a ring-shank nail has been taken into consideration by the reduction in required length but is not taken into consideration on B1-1802

2 inch nail diameter???

Wow! The fastener would be wider than the … I think length was to be 2". Why is everyone ignoring the code about minimum deck thickness?

There 2 types of 8d nails. The common 8d which is 2.5" long and the 8d sinker or gun nail that is 2.375" long.

I thought we killed that one already. 7/16 osb is stronger than 1/2 plywood.

you ought to see the nail gun that shoots it. LOL I think i meany in length

Came upon this topic researching something else and couldn’t resist making a comment. I’ve been doing these inspections probably longer than anyone else and all I can say is, come on guys. If in doubt, always error on the side of the client and let the underwriter make the decision, which I’ve found when it is this close, they have always gone with me. Besides, they have the picture and it is on them if they make the wrong call; also, I can make an argument that this is an 8d nail if ever questioned using the same explanation that has already been given by those calling it an 8d nail.