Are Metal Roofs Magnets for Lightning?

If you don’t understand lightning and why, how and where it strikes, you might believe that a metal roof on your home could become dangerous by attracting lightning during a thunderstorm.  If you do understand lightning, however, you know this is not the case.

Lightning can shoot from cloud to cloud, or it can come out of a cloud to strike the earth.  In the latter instance, several factors determine how the earth-coursing lightning will behave.  We’ll look at elements of a lightning strike momentarily, but first let’s understand what lightning is.

This thing called lightning

Lightning happens when static electricity in the atmosphere is rapidly discharged.  Usually occurring during a thunderstorm, this discharge produces a flash.  You can observe lightning during a storm and see if it is striking between clouds or shooting from a cloud to the ground.  The light is black body radiation formed by the extremely hot plasma created by the electron flow.

Lightning is very dangerous to humans, as we all know.  Fortunately, because of lightning’s typical behavior, it’s highly unlikely that a person walking on the street will be struck by it.  This is why we have the phrase, “That’s about as unlikely as being struck by lightning.”

But lightning can and does strike various objects, and that’s what we want to explore.

Elements of a lightning strike

First: lightning usually will strike the highest object in its vicinity regardless of its composition.  Tall trees are often victims, as are tall buildings.  Lightning rods are placed very high above other structures because we know that in most cases lightning will hit them first.

Metal is not an attractor of lightning – when lightning strikes, it will strike anywhere and hit anything in its path.  Where roofs are concerned, the important point isn’t whether or not a roof attracts lightning but rather how lightning will behave once it hits the roof.

Now, while metal doesn’t attract lightning, it is a fine conductor of it.  When lightning hits a large metal structure, the metal absorbs the lightning and distributes it throughout the surface.  On the other hand, roofs with poor conducting materials (asphalt shingles, clay tiles, etc.) will take the full brunt of the lightning’s heat at the point of impact, resulting in potentially significant damage and possibly a fire.

A metal roof won’t burn from a lightning strike.  Like the metal lightning rod, it disperses the power of the lightning, softening the blow, so to speak.  Compare that to a tall tree that is the victim of a lightning strike: the tree easily can catch fire and burn and smoke for hours.

So the bottom line is, we can’t prevent a lightning strike, but should it hit the home we’re living in, we should expect little or no damage if our roof is made of quality metal.  If it’s made of something else, we might be looking at a long road to recovery.

If you’ve been thinking of adding a new metal roof to your home, contact the experts at Advanced Aluminum of Lakeland, FL.  We produce outstanding metal roofing products for leading contractors in our region and can share with you the numerous benefits of metal roofing over traditional roofing materials.  Reach us at (863) 648-5787.