Do Metal Roofs Attract Lightning?

Extensive research has proven that metal roofing is no more likely to attract lightning than any other roofing material.  

Metal roofing is an excellent choice for homes in lightning-prone areas due to its non-combustible nature and superb Class A fire-resistance rating. When lightning strikes a metal roof, its effective conductivity reduces the voltage and fire risk as the electrical current follows a direct path to the ground outside the house. 

The MCA technical bulletin titled "Lightning Strikes and Metal Roofing" asserts that the type of material used in roof construction does not affect the likelihood of a lightning strike.

However, various other factors can influence the risk of a lightning strike, which will be elaborated upon. When contemplating lightning, it is important to assess both the probability and the potential consequences of a lightning strike.

Metal Roofing and the Probability of a Lightning Strike

Essentially, nothing can be done to lessen the probability of a lightning strike. Lightning strikes are, however, influenced by several factors.

• Topography - is the building on an elevated site or a low-lying area? Lightning strikes are more likely at higher elevation since it is drawn toward the highest points in any given area.
• Building height - the highest building relative to those around it is most likely to be hit by lightning.
• Building size - a larger surface area is more likely to be hit than a smaller one.  
• Geography - is your location more or less prone to lightning activity?

The above four factors may contribute to the probability of a lightning strike.

Metal Roofing and the Consequences of a Lightning Strike

What happens when lightning strikes a building? Lightning is a significant threat to people and property and should be taken seriously. A few things affect the seriousness of that threat, including:

• Construction materials - various materials possess electrical conductivity, which means they can facilitate the flow of electric current. Examples of such materials include copper, aluminum, silver, gold, and iron. If the framing and roofing of a structure are electrically conductive, the charge from a lightning strike will pass through these materials and not build up heat through resistance, reducing the possibility of fire. 
• Building materials - if the building is constructed with non-combustible materials, it will not be a fuel source for a possible fire resulting from a lightning strike.
• What's in the building - sensitive flammable materials are susceptible to ignition.

Lightning Rods on Metal Roofs Reduce the Threat Of Lightning 

In the event of a lightning strike on a building equipped with a metal roof and lightning rods, the electric charge would be swiftly directed through the conductive metal. This redirection ensures the surrounding area's protection and minimizes fire risk. These lightning rods are made of highly conductive and non-flammable metal, ensuring the voltage is efficiently dispersed without the risk of fire. 

For optimal lightning mitigation strategies, it is advisable for building owners and homeowners to seek advice from local experts who can assess their specific location and conditions.

If you are concerned about metal roofs and lightning, you'll love our Ultimate Guide to Metal Roofing.