What happens when lightning strikes a metal roof?

If you are considering getting a metal roof for your house, you may have asked the question, but what if we get caught in a thunderstorm?

This is a common concern for many people, and extensive studies have proven that metal roofs are no more likely to attract lightning strikes than any other type of roofing material. This is understandable when we associate metal with conducting electricity. However, the fact is that metal roofing, as a non-combustible material with the highest Class A fire resistance rating, is one of the best materials for homes in lightning-prone areas. When it comes to lightning strikes and roofing, the most important thing is fire prevention. If the roof is covered with combustible materials such as wood shingles, asphalt shingles, a lightning strike can easily cause a fire. Therefore, it is recommended that if you live in an area where lightning strikes are frequent, metal roofing should be your first choice. 

What Happens to a Regular Non-Metal Roof?

At first glance, a non-metal roof may seem like a safer option. However, the opposite is true. One of the most dangerous consequences of lightning is the fires that result from it. When lightning strikes flammable roofing materials, such as asphalt shingles, or wood shingles, it immediately ignites, causing your house to catch fire. Without a clear path to the ground, lightning can also "jump" between walls and floors as it seeks its way downward, creating a danger to you. Additionally, if lightning "finds" your electrical wiring system, it can begin to use this as a path to the ground, causing a potentially explosive surge that can damage your appliances, start a fire, and endanger your family.

What Happens to Metal Roofs During a Lightning Strike?

In contrast, lightning that strikes a metal roof is immediately and safely contained. Metal roofs are designed with an aluminum rod protection system that spreads the energy from lightning contact before transferring it safely to the ground outside the house. This means lightning is immediately provided a path of least resistance that does not involve entering your home or striking your electrical wires. By providing a concentrated "hot spot" that safely channels lightning energy, metal roofs protect against the chaotic nature of lightning strikes. The multi-layered steel structure of a metal roof can also withstand the impact of lightning, shielding the house below from the effects of a storm.

What is the best roofing material for lightning protection?

Here is a brief look at how common roofing materials perform during lightning and fire.

Asphalt Shingles
Asphalt shingles are one of the most common roofing materials, mainly because they are the cheapest. Considering that asphalt shingles do not conduct electricity and, as a petroleum-based product, are flammable, they are not the best choice for homeowners in areas prone to heavy storms.

Clay or Concrete Shingles
Concrete or clay shingles are naturally fire-resistant and generally have a Class A fire rating. It is important to note that while clay or concrete tiles have excellent fire resistance, there is still a lot to be aware of when it comes to performance. Simply walking on a shingle roof can cause damage, so homes in areas prone to hail, hurricanes, tornadoes, or high winds may want to consider a more rugged roofing material.

Wood Shingles
When it comes to fire protection, wood roofing is one of the worst choices. Wood is obviously a combustible material, so it requires a lot of treatment and flame retardants to achieve a Class B or Class A fire rating.

Metal Roofing

As mentioned earlier, metal roofs do not attract lightning. In fact, metal roofs can greatly reduce the risk of lightning strikes. As a naturally non-combustible conductive material, a metal roof with a lightning protection grounding system installed provides an easier path to the ground, dispersing the force from a lightning strike and preventing concentrated hot spots. Almost all metal roofing products have a Class A fire rating and can withstand almost anything Mother Nature has to offer.

How Else Can a Metal Roof Protect My Home?

A metal roof is perfect for any home located in an area with unstable weather-and that's not just limited to lightning strikes. As mentioned above, many other traditional roofing materials can prove to be highly flammable under the wrong conditions. Not so with a metal roof. If a spark from a nearby fire lands on your roof, there's no risk of it spreading to your property. At the same time, the incredible durability of a metal roof means it can protect your house from winds of up to 140 mph without the slightest corrosion. That means your home will be protected for a long time to come.