Deck nailing question. I know what I suspect, but need an outside opinion please. The pictures show what I found as shiners (in addition to the original staples) and the deck thickness on a new re-roof. The nail measures out at about 1 11/16 and the deck measures at about 7/16 when you take away the thickness of the modified bitumen underlayment. Even if you round up to 1 3/4 for the nail and 1/2 inch for the deck it still puts you at 2 1/4 inches and the nail is certainly not a ring shank. Did this guy get duped and does it qualify for level “C” Nailing. The pattern is 4" in case you’re wondering so there isn’t an issue there. These almost measure out the same way the old spiral shanks do but without the spiral. They look closer to the 6d wire gauge too but I didn’t have my caliper with me to verify. There also is a permit, but I know when a roofer sends in the nailing testimony the building department generally doesn’t inspect the nailing is ensure it is actually up to code. Please send me some opinions.
I forgot to mention, this home was built in 1991 and most likely this is the first re-roof.
Looks and sounds like a 6 to me 
First of all, that nailing pattern looks like you are at the panel EDGE and not the field. If it was just renailed for a reroof, chances are most likely 8d nails were used. I have seen some 8d’s at 2 1/4" to 2 3/8. If it was a 6d, it would be right at 2" total.
I say 8d, but you should be doing the spacing check at the field truss.
The spacing is not the issue. It’s 4" to 6" throughout the decking. How can you tell from that terrible picture that it’s at the edge anyhow, just curious? Maybe I need to be schooled. It’s actually shorter than 2 1/4, I’m just giving the benefit of the doubt by up to an 1/8th inch simply because the head might not be seated. Some of my question is that isn’t it required to be re-nailed with a minimum of 2 1/2" ring shank nowadays anyhow? Isn’t that the re-nailing standard as of 2007 or an I off base? When I normally see a re-nail, it is obvious that they have 2" reveal (with deck thickness at 7/16" average) and ringed shanks.
I was a framer in my past life…I can tell from the shiners. You are correct about using ring shank nails on re-roofs, but not all roofers follow that rule due to cost, and some AHJ inspectors don’t check it. Those nails were probably foreign made and just a little shorter than standard, but I still would go with 8d.
Not all nails advertised as 8d are 2 1/2 inches there is a lot of variation now a days, http://www.homedepot.com/p/Grip-Rite-11-1-2-x-2-3-8-in-Smooth-Vinyl-Coated-Steel-Sinker-Nails-1-lb-Pack-8CTDSKR1/202308520
Your just going to have to make a judgement call on this one, because it is sticking out OVER 1.5 inches, I would say 8d.
I appreciate the insight. Some of my concern is that if they should be ring shank and are shorter than what they really should be, does it provide a risk to me if I show them as 8d. This roof was put on within the last month or two. Also, what is the cut off for you? Anything that would be 1 1/2" or less? 1/8" is not a lot of difference and hard to tell, especially if the worker just happened to have the air up and was sinking the nails a little too much. Is there a good rule of thumb that I can follow? This one is right on the border for me. It’s most likely a 7d nail sold as 8d from what it sounds like you’re saying, but aren’t 7d nails the same diameter wire as 6d and 8d have larger shanks? Please correct me if I’m wrong cause this is all a learning experience to me and you obviously have done this a lot longer… 6d and 7d are 11 1/2 gauge (or .113 inches) and 8d is 10 1/2 gauge (or .131 inches) . Or does that only apply to common nails?
Thank you for adding to this. It seems 1 1/2" is the cut off assuming 1/2’ decking.
Got to keep it simple on these. We are not doing engineering analysis on roof decking attachment. I’ve heard the 7d argument before, but nails sold to framers and roofers will not be labeled as 7d. They may be the same size as 7d, but they are labeled as 8d for a particular application. Shank sizes will vary also. Check out a twist shank 8d gun nail, they are probably the same thickness as a 6d. Nobody uses 6d nails to nail down a deck anymore. 8d nails have been required for deck nailing since 1994.
What you said right there clears it up for me. Thank you. The form always looks for “weakest” forms. A 9" nailing pattern defaults to 12" etc. so I wasn’t sure if the same applied here. If you’re saying 7d nails are sold as 8d that makes sense to me and clarifies a lot and basically means 7d is equivalent to 8d in the real world. I try to get the client all the credits I can but wanted to make sure I can justify it for these instances. The older spiral shanks have always received the credit and they are close to the same measurements, but I wasn’t sure about this type and if it’s accepted. As far a re-nailing to code, I suggested he contact the roofer. I’m fairly sure these aren’t properly re-nailed even if the insurance company does give deck nailing credit. Thanks again for the info. I at least have a reason why the 7d is equivalent to 8d.
Now you are getting it. Try not to overthink this, just confuses everybody involved, including the underwriters. Opening protection is a different story.
I would go with 8d, many companies come up short on nail length, never seen any come up long!
This is funny because years ago I brought up the difference in nail sizes and showed them at a meeting. Some of the inspectors made fun of it, but today we are still getting the same questions and those inspectors are no longer around.
Simply 8d(penny) is the weight of the nail not the length. As mentioned the nail length can vary. Some are ring shanked, twisted shank, common and sinkers.
So what would you have called it based on his examples?
It could possibly be an 8d, but was it require to be re-nailed when the roof was done? I have a fool proof way of knowing(with owner’s permission), on the edge use vise grips to pull the nail through and you can get an accurate measurement.
The 1802 form says: “8d common nail.”
An 8d common nail is 2 1/2 inches long. Period.
Other types of nails, (not common) may have different lengths and diameters. They don’t meet the requirements stated on the form.
Never thought of that. Thanks for the idea
I have never shared that one before, you should feel lucky. 
I thought we were doing NON-invasive inspections, John…lol