Roofing nails and lighting

#1

So I’ve had a first and would like some input. I’ve been in this business a good amount, handyman, electrical and machinery troubleshooting, as well as volunteer fireman for many years but haven’t experienced this. I was inspecting a roof deck from the attic and the nails weren’t there and scorched sheathing where they were along the top 1/3 of the roof. There was snow and ice on the roof, so I wasn’t to examine the roof.

My thoughts move to lightning passing through the shingles and zapping the nails. Has anyone ever heard or experienced this?

#2

Let’s see those pics!!

2 Likes
#3

Welcome to our forum, Michael!..Enjoy! :smile:

Yes, pictures may help, more.

#4

Welcome to the forum, Michael, Enjoy!! But we can’t help with no pics. sounds odd,

#5

The burned spot are where the nails would be and is consistent across the top 1/3 from the ridge. As you can see in the last photo of sheathing towards the soffit the nails are there and protruding.

I can see a few nails, but the sheathing is definitely scorched and I caught a few whiffs of char.

Have fun

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Michael Lesh
CAI Ohio

#6

Moisture stains and rusted nails, due to excess moisture in the attic space. Looks like microbial growth in the 4th pic, possibly from an exhaust fan venting into the attic. Possibly a combination of inadequate attic insulation/ventilation as well.

4 Likes
#7
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#8

My guess:
This roof originally had radiant barrier foil fastened to the underside of the sheathing. It was struck by lightning because the foil attracts lightning. It fried the nails and damaged the original shingles enough to require their replacement (including the nails) but the sheathing survived. The strike created enough short-term, intense, residual heat to discolor the surface of the insulation and the wood trusses, and that’s why the trusses are unusually dark. It doesn’t all make a lot of sense because lightning does weird things.
https://hinarratives.com/roof-structure/roof-sheathing/
Why wasn’t the sheathing discolored except at the location of the original nails? I dunno. Maybe it was protected by the foil.

#9

Mike, Imo it looks like 2 different conditions - the assumption of charring looks correct, but the reason therefore?? Who knows. I think Junior has it right on the last (4th) picture, probable WDO.