Lightning Strikes on Residential Roofs – Causes, Damage, and Prevention

Avoid costly structural damage and destructive power surges when lightning strikes your home. Understanding the power lightning carries and how to divert it will help prevent catastrophic lightning damage to your home.

New Image Roofing Atlanta gathered crucial information about how lightning strikes affect a home’s electrical systems, appliances, and structural integrity and what you can do to mitigate them.

How Lightning Forms

Lightning forms during thunderstorms resulting from imbalances between positive and negative charges in the atmosphere. Ice crystals and water droplets collide in a storm, creating an electrical charge buildup. A cloud’s upper portion typically holds positive charges, while the lower section becomes negatively charged.

When this imbalance grows large enough, nature corrects it by discharging electricity as a lightning strike. The bolt either moves within the cloud, between clouds, or between the cloud and the ground. A lightning strike to the ground occurs when the negative charge at the cloud’s bottom seeks to connect with positive charges on the Earth’s surface.

What Attracts Lightning?

Lightning seeks the least resistant path to connect to the ground. This often means it targets tall or conductive objects. Here are some common attractors:

Tall Objects – Lightning frequently strikes the highest point in an area, like trees, utility poles, or a home’s roof.

Conductive Materials – Lightning is attracted to conductive materials like metals. Roofs with metal flashing or metal objects mounted on them (like satellite dishes, antennas, or chimneys) may become targets for lightning.

Water and Wet Surfaces – Water is an excellent electricity conductor. If a roof is wet, it can enhance conductivity, making it more attractive to lightning.

Note: Lightning doesn’t need to hit the exact rooftop to cause damage. Even nearby strikes can result in electrical surges and fires within your home.

Energy in a Lightning Strike

Lightning is powerful. The average lightning bolt can contain up to 1 billion electrical volts with temperatures exceeding 50,000°F (five times hotter than the sun’s surface). The energy released by a lightning strike can be up to 300 kilowatt-hours in a fraction of a second. This immense energy release can damage everything, including electronics, electrical wiring, and a home’s structural integrity.

Potential Damage to a Home’s Structure and Electronics

A direct lightning strike to a residential roof can cause various damages, including:

Fire Damage – The intense heat from a lightning strike can ignite combustible materials like wood and shingles on a home’s roof. Even metal roofs are not immune to fire risks since the heat can reach high enough temperatures to cause surrounding materials to catch fire.

Roof Damage – A lightning strike’s force can shatter roof tiles, damage shingles, or puncture holes in the roof. This leaves the home vulnerable to further damage from rainwater entering the structure.

Electrical Damage – Power surges are among the most common lightning results. When lightning strikes a home or nearby power lines, the surge can travel through electrical wiring, destroying appliances and electronics. Devices like televisions, computers, and HVAC systems are particularly vulnerable.

Plumbing Damage – If your home has metal plumbing, lightning can travel through it, leading to ruptures, leaks, or electrocution hazards.

Structural Damage – A lightning strike’s force can cause cracks in walls, damage to chimneys, and even foundation movement in extreme cases.

Who to Call After a Lightning Strike

If your home is struck by lightning, you should immediately ensure your family’s and your property’s safety. Here’s who to contact:

Emergency Services – If you notice fire, smoke, or gas leak indications after a lightning strike, call 911 immediately. Lightning-induced fires can spread quickly, and first responders can prevent an issue from becoming catastrophic.

Electrician – Even if there are no immediate damage signs, have an electrician inspect your home’s electrical system. A surge from a lightning strike can cause hidden damage to your wiring, outlets, and appliances that may lead to future problems or fire risks.

Roofer – A licensed professional roofing contractor should inspect your roof for any damage caused by the strike. Even small punctures or cracks in the shingles can lead to leaks and water damage over time.

Plumber – If your home has metal plumbing, a plumber should inspect your pipes for damages. Lightning can cause holes in pipes or weaken them, leading to potential leaks or bursts later on.

Insurance Company – Lightning strikes are usually covered by homeowner’s insurance policies. Contact your insurance provider as soon as possible to report the damage and start the claims process. Be sure to document all visible damage and keep any receipts for emergency repairs.

Watch this video to learn more about insurance coverage and deductibles.

Preventing and Diverting Lightning Strikes

While you can’t stop a lightning strike from happening, there are several steps you can take to minimize damage risks to your home:

Install a Lightning Protection System – A lightning rod system is designed to direct a lightning strike’s energy safely into the ground, preventing damage to your home. The system typically includes rods, conductors, and ground rods that create a low-resistance path for the electricity to follow.

Surge Protectors – Install whole-home surge protectors to help guard against power surges from lightning. These devices are connected to your home’s main electrical panel, preventing excess electricity from reaching your outlets and appliances.

Unplug Electronics – During a storm, it’s best to unplug sensitive electronics like televisions, computers, and kitchen appliances. While surge protectors help, unplugging devices offers maximum protection from surges.

Tree Trimming – Trees near your home can become targets for lightning. Keep them trimmed and ensure that large limbs are not hanging over your roof. If lightning strikes a tree, falling or ejected branches can cause significant damage to your roof.

Use Non-Combustible Roofing Materials – If you live in an area prone to lightning, consider using fire-resistant roofing materials like metal or tile. These materials are less likely to ignite compared to traditional asphalt shingles.

Read more about lightning strike prevention HERE.

Lightning and Residential Structures

In this article, you discovered how lightning strikes affect residential structures, the damage they cause, how to divert them, and what to do after one.

Knowing how to divert or prevent residential lightning strikes can help avoid costly structural and electrical damage.

Ignoring the need for lightning protection systems and using non-conductive material in your home’s construction can lead to catastrophic damage to your structure and electronic systems/equipment, resulting in an uninhabitable residence.

Sources:
noaa.gov/jetstream/lightning/lightning-safety
nvlpubs.nist.gov/nistpubs/Legacy/IR/nistir89-4113.pdf
nfpa.org/news-blogs-and-articles/blogs/2024/09/11/nfpa-780-and-protecting-buildings-from-lightning-strikes