Is Your Metal Roof Safe in a Lightning Storm?

According to where you live in Australia, the risk of a lightning strike can vary significantly. Homeowners living in certain parts of the country are more likely to worry about the risk of a lightning strike and many people believe that their metal roof can increase the risk of lightning damage. Find out if this assumption is correct, and learn more about the steps you can take to protect your home from lightning.

Understanding the risk of a lightning strike

The probability of a lightning strike depends on several factors, which include:

  • The topography of the land where you live (that is, if you live on a hill).
  • The size and height of your home.
  • The proximity of your home to other vulnerable structures, such as trees.
  • The relative frequency and severity of thunderstorms where you live.

Some Australians experience a huge number of lightning strikes. For example, the Top End of the country encounters many strikes every year. Indeed, a single thunderstorm in Darwin once caused 1,634 lightning flashes in just a few hours. In other parts of the country, homeowners would see fewer strikes than this in an entire year.

Metal roofs and lightning strikes

Lightning occurs when an electric current flows between the ground and the sky. A single flash of lightning can carry millions of volts, so it's unsurprising that many people worry about the potential havoc one strike could cause.

Some homeowners believe that a metal roof increases the risk of a lightning strike because metallic materials conduct electricity. In fact, a roof's construction material does not influence the risk of a lightning strike.

Lightning looks for the path of least resistance. The electrical charge must pass through the air before making contact with the ground, so taller structures (including buildings and trees) are at higher risk because the lightning doesn't have to travel so far. As such, a plastic roof is at the same risk of a lightning strike as a metallic one, when you take all other factors into account.

While the construction material does not influence the risk of a strike, the type of roof can change the impact the electric charge can have. Nonetheless, a metal roof is still one of the safest construction materials in a lightning storm.

The risk of damage from a lightning strike

The electricity from a lightning strike passes through some materials more easily than others. As such, if the charge hits a metal roof, the material will conduct the electricity quicker and more efficiently than other materials. A roof that is not as conductive as metal will convert some of the electrical energy into heat. In turn, this increases the risk of a fire or explosion.

Ironically, during a thunderstorm, you are probably safer inside a metal building (or a home with a metal roof) than anywhere else.

Lightning strike protection and metal roofs

Lightning safety systems (lightning rods) filter the flow of electricity safely away from the home. Lightning rods help homeowners in vulnerable areas cut the risk of damage from a lightning strike. The rod becomes the highest point of the building, which means the rest of the house is unlikely to suffer a strike.

If your home has a metal roof, you probably don't need a lightning rod. In some ways, the metal roof acts like the rod, helping to disperse the current more safely. You should only ever consider a lightning safety system if you live in a high-risk area, such as at the top of a hill.

Contact a local roofing company like A.C.R. Roofing Pty Ltd for more advice. A professional can help you understand if a lightning safety system is of any use to you. If you decide to install one of these systems, make sure you arrange for a professional to carry out the work. Safe placement of the system is vital, as you could otherwise inadvertently increase the risk of damage to your home.