Acceptable # of shiners

Hi Island Roofing: I appreciate your response.

However, the 8 penny nails I am viewing from the attic are supposed to hold down the new plywood. The nails missed the rafters. Over time the nails may back out through the plywood and then the roofing material. This is not normal workmanship. My roofer has apologized for the poor workmanship and we are trying to come up with a good solution. Any further thoughts?


Ah i apologize. I got confused when you called them “shiners” as that’s not what they are. Good news is I wouldn’t be concerned about those nails backing out and causing issues. I don’t find them backing out any more likely than any of the 1000s of roofing nails used on your job (and every other shingle job) backing out of the plywood. My only concern would be is your new plywood fastened well enough with so many missed nails.

Your new sheathing is NOT nailed properly if nails aren’t hitting rafters. A dozen or two wouldn’t concern me. 250 would.

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Hi IslandRoofing: I feel somewhat comfortable about the new plywood being properly fastened since the galvanized roofing nails penetrate into the old plywood sheathing. But, I’m still worried about the 8 penny nails backing out over time. Do you know if an adhesive applied from the attic side could help hold the 8 penny nails? Thanks.

Hi Tileman: Any thoughts about how to fix this situation without tearing off the new roof and sheathing?


I think you have nothing to worry about at all with the nails backing out. As I said, they are no more likely to back out than all roofing nails used on your job. Think about it, how is an 8penny nail in plywood more likely to back out than a roofing nail in plywood? However, if it will give you piece of mind go bend them over with a hammer (that would lock them in place far better than any sealant would). Like I said earlier, I’d be more worried than your new plywood isn’t fastened to your rafters more than anything.


I agree with Island. I would not worry about anything backing out and his solution is good for uplift.


Can you post a picture?

I am worried that bending the nails from the attic could accidentally cause the nails to penetrate the underlayment and/or asphalt shingles. I would prefer adhesive as a solution.

Here is a picture:



Just bend them over with a pair of plyers, they won’t pop back up.

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I think you really need to get over this unrealistic fear of those nails backing out through your shingles. Sorry if i sound rude but i’ve given you my best recommendation several times but you keep wanting to use sealant (which no one will tell you is gonna benefit at all). However, if it helps you sleep at night go put sealant around them from the attic.


Also, you still haven’t answered why you think these smooth shank 8 penny nails (into 2 layers of 1/2" plywood) are such a threat to back out over time, however the 1000s of smooth shank roofing nails (into 2 layers of 1/2" plywood) are no threat.

Hi IslandRoofing: In answer to your question: Since the nailing pattern of the plywood was non-standard, I spoke with several roofers and contractors. I was not able to achieve a consensus. The reactions were from not worrying about it to anger that the roofer did such a sloppy job and that I should demand that they re-roof. I thought that I would reach out to this community in order to get more clarity on my options. I don’t mean to be disrespectful, but am merely trying to become more educated. Basically, I was sold a 25-50 year roof and am not comfortable with this aspect of the job.

Those roofers who said I had a problem advised me that a house “breathes” and with the expansion and contraction, those nails could work their way up over time. The 8 penny nails are very smooth due to the coating that allows them to operate effectively in the nail gun.

The reason I am more worried about the 8 penny vs the roofing nails: the roofing nails, are hot dipped galvanized and should have more bite.

I want to thank you again for bearing with me as I further my roofing education.

If you were a friend or family of mine and had the same issue and concern what I would do would be go in the attic and bend the nails over with a hammer. I would then go home and sleep like a baby without a care in the world of those nails ever backing out (or backing out while i was bending them over). Take that for what its worth. Sealant is a giant waste of time. Btw unless you choose one of the very expensive specialty shingle lines your roof its not gonna last close to 50years, that’s a b.s. marketing ploy manufacturers have been saying the past 10 years. 20-25 is much more realistic.

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I think the future issue you have coming is the plywood lifting and moving.

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Plywood over plywood is a no no.

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I have heard that on this forum but can’t remember the basis for it. It’s not something we’ve come across but please educate me so I can sound smart to a customer someday.

If you are going over plywood/osb the stuff you are going over probably isn’t the best to begin with.

The underlying deck may deflect a bit and not let the nail adequately penetrate it.

The underlying deck in this case can act as a spring and over time push up the roofing nails that didn’t fully penetrate both decks.

Plank decks are more rigid by nature and are also 3/4" of real wood that doesn’t deflect much when spaced 16" on center like most old houses are.

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You are absolutely correct when you say
About roofing nails popping up
Due to some roofing nails not penetrating the deck on the bottom.

But i have some good news to report.
It seems these popped up nails show themselves within the first year.
After knocking them down,
They stay down and more dont pop up over the years.
That is what i have experienced any way.

So i guess i am saying that it is not a total disaster…