Re: Can a lightening strike cause nail pops on your roof and dry wall screws po

Hi Kim!

I'm familiar with some of the electrical effects of lightning, but not so familiar with the effects of the shock wave from lightning-generated steam explosions. When lightning strikes a tree, it dumps its energy into the wet wood and creates a steam explosion. If the lightning strike knocked you backwards, and if it shattered nearby windows, then this shows that the lightning created a significant "overpressure". In other words, it was just like any other large explosion. Yes, the overpressure from an explosion can shatter windows and distort walls and roofs. If nails popped out, it probably happened when the wood was suddenly flexed during the pressure wave. How distant was the tree? If it was closer, perhaps the overpressure from the exploding tree would have caused far worse damage to the buildings.

Also, a lightning strike proceeds into the ground and sometimes follows the roots of trees. If the earth is at all damp, then we might expect steam-explosions to occur underground and not just inside the shattered tree. In your case this would be like setting off dynamite under the ground. The waves might damage any underground objects such as sewer lines, basement walls, etc. Shock waves in solids and liquids can be far more destructive than the same wave in air (this is why dynamite can kill the fish in a large pond, but the same dynamite just makes a loud noise in the air.)

Here are some links:
Lightning Safety Institute
Lightning and Electric Shock Survivors
Thrown by electric shock: muscles & exploding steam