You might think lightning rods are common, but on residences they are not so common, at least in Northern Virginia.
I see them more and more on schools and commercial buildings with metal roofs. And I see them on statues, and some Federal buildings. For example, when the Capitol Building was repainted and refurbished in the 90s, the statue (the image of Columbia) on top was left on the lawn for a while. When they put it back on top, they added "lightning points" to hopefully send any strike away from it and the building. There are also "lightning points" on the Washington Monument. There are many such points on each, tipped with platinum.
Copper and its alloys are the most commonly used metal in lightning rods and points.
The lightning rod was introduced to America in 1749 by Benjamin Franklin.
He called it a "lightning arrestor," but it was commonly referred to thereafter as the Franklin Rod.
He thought lightning was electricity, and that if he sharpened a metal rod into a point and put it on top of a tall building he could prove that. He said, "The electrical fire would, I think, be drawn out of a cloud silently, before it could come near enough to strike...."
His impatience waiting for the tall steeple of the Christ Church in Philadelphia to be completed spurred him to send up his famous kite and key. His experiment worked. Others have died trying to mimic it!
A lightning rod is essentially a metal rod, or rods, mounted on top of a building or high place, and bonded to a cable, or electrical conductor.
This cable is itself connected to a long rod, or electrode, buried deep into the earth.
This is a house wrapped entirely with aluminum siding.
It is located on top of a rural hill at the foot of the "mountains" between Round Hill and Berryville, Virginia.
This house is all by itself.
Being surrounded by an electrical conductor, aluminum siding, the homeowners decided at the outset to equip it with lightning rods.
There are rods all over the house, and all connected to each other and to cables, which themselves are bonded to three electrodes buried around the house.
Lightning, it is hoped, will find the rods preferential to striking the house, and be directed safely into the ground.
The cable is large, and braided.
It is bare.
The bonding is significant, to make sure there is a very solid connection.
And the rod is 10' deep.
The homeowner reports that to their knowledge, over the last 19 years, lightning has never struck the house.
But it is protected!
I do not see this very much. In fact I can't remember the last time I have seen such an array of lightning rods!
Certainly it is good to see!
My recommendation: it's good to see a lightning rod where it can be of use! Again, I do not see them very often on residential structures. They are becoming more and more popular for commercial use however. And that, perhaps, because of the sensitive electronic equipment and computers in modern structures. When a building is alone and lightning vulnerable, like this one is, perhaps a lightning rod or two (or ten!) would be a good way to go!
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560