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I live in Northwestern Florida (Crestview), and I never go in my attic during the summer because it's tooo hot.

In July we got a new roof and solar panels. I had to go in the attic to retrieve Halloween decorations and almost hit my head on these nails. Why are the nails so long and showing?

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    How long is long? Most roofing nails will show about a 1/4 inch. The panel screws might be longer, but should not be much over an inch.
    – crip659
    Commented Nov 26, 2022 at 21:01
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    It's not uncommon for roofing nails to penetrate beyond the sheathing, When you think it thru, know that the sheathing is probably only 1/2" thick. If the nails were so short that they wouldn't penetrate, they could be so short that they wouldn't hold the shingles in place properly. In FL I believe you get the occasional hurricane (sarcasm intended), Having the shingles attached securely would minimize damage.
    – George Anderson
    Commented Nov 26, 2022 at 21:08
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    You're lucky you "almost" hit your head. I've been doing this stuff for 55 years and still hit my head on nails. :-)
    – JACK
    Commented Nov 26, 2022 at 22:09
  • Could you acquire some thick dense rubber sheet and cover the points? Hold them in place with aluminium saddles or brackets. Easily removed if required. Or perhaps get some old fluourescent-light covers and fit then over the problematic protrusions? Again, secure simply and easily removed...
    – Magoo
    Commented Nov 27, 2022 at 7:01
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    Related question, but not a duplicate: diy.stackexchange.com/questions/80951/… (This question asks why they're there; that question asks what to do about it.)
    – Andrew Leach
    Commented Nov 27, 2022 at 9:52

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Nails that show through 3/4" or more are perfectly common and done properly. You need that, or your shingles wouldn't be properly attached.

If you keep perforating your head when going up there, get a cheap hardhat and leave it by the attic hatch.

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I agree with most other answers. Is it possible you simply never noticed the exposed nails from the original roof? I couldn't imagine no nails showing through at all prior to this. It's very common. I would say they shouldn't be extraordinarily long (not more than 1/2" sticking out)
A roofing nail must be a minimum of 1¼ inches long for a single layer roof. International Building Code sates "the nail should be long enough to penetrate fully and extend at least one-eighth of an inch through the roof deck."

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This might be a regional thing - Here in New Zealand, exposed nail ends would be a sign of lazy workmanship using overly-long nails, or an overpowered nailgun here causing over-penetration and likely leaks.

Here in New Zealand, roofing fasteners are required to go into a purlin or similar, and missing the target happens, but leaving it would be poor workmanship.

I'd say not normal at all but your locale/region may differ. Possible solutions:

  1. hammer the nail ends over so they are somewhat sunk into the wood, but this risks upsetting the seal on the top and causing a leak in the future.

  2. use a hacksaw to trim every nail that you can get to. For thin wire-nails you might only need to use pliers.

  3. use a small grinder with a cutoff wheel to do the same (but sparks in your roof space are an absolute definite fire hazard so consider your risks)

  4. Insulate and line and ventilate the attic space so its more useful - the insulation and lining will "thicken" the ceiling and cover the roofing nails. Kind-of overkill solution.

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    Out of curiosity, what's typical roof sheathing over there? (In the OP's case, it's probably 1/2" osb.)
    – Aloysius Defenestrate
    Commented Nov 28, 2022 at 4:06
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    @AloysiusDefenestrate the common one is long-run "corrugated iron" which is really painted steel sheets with a longitudinal reinforcing pattern. Old sheets were 6 or 8 feet long, but then they needed overlaps which were a source of leaks. Underneath that is building paper. Very old houses might have timber sarking but the iron is nailed or screwed to purlins that are laid on top of trusses, or older houses had rafters with short dwangs/nods between. So the screws/nails would punch through raised parts of steel, and secure to wood in a neat line. Shingles are totally not a thing in NZ.
    – Criggie
    Commented Nov 28, 2022 at 9:23
  • Exposed roofing nails in an attic are not "a regional thing" nor a sign of poor workmanship. Exposure is normal and done purposely. A roofing nail must be a minimum of 1¼ inches long for a single layer roof. International Building Code sates "the nail should be long enough to penetrate fully and extend at least one-eighth of an inch through the roof deck."
    – Brian Miller
    Commented Dec 19, 2022 at 0:52
  • @BrianMiller sorry - "international building code" ? Most first-world countries have their own legally enforced building standards which do not have to be compatible. Nails that have missed their target and are exposed are poor workmanship. That your roof "deck" is thin is a regional thing. Here, fasteners are required to go into purlins. Must be a regional difference.
    – Criggie
    Commented Dec 19, 2022 at 1:40
  • First of all, I'm referring to the US IBC - I don't care about anywhere else. You seem to be misunderstanding how things work. Missed their target? Exactly what target are you talking about when nailing a huge field of shingles into the same huge field of sheathing? Are you referring to missing the rafters when nailing the sheathing? That would be an entirely different topic - those are referred to as "shiners" in the trade, but this topic has to do with the roofing nails sticking through the sheathing on the attic side - absolutely normal and means the proper length nails are being used. SMH
    – Brian Miller
    Commented Dec 23, 2022 at 18:53

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