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How Homeowners Can Protect Against Wildfire

Robert Ferrell
October 20, 2020

In recent years, wildfires have become an ever-increasing concern in the United States. Even with their growing frequency and volatility, there are ways to minimize the consequences of these deadly conflagrations.

Research into past fires has yielded evidence that building construction, code compliance, and maintenance help prevent property damage. While not the only factors affecting risk, these considerations all play important roles in reducing property risk from wildfires.

In this article, we’ll cover key steps to mitigate loss and give you resources to share with your homeowners policy customers so they can better protect their homes.

What is home hardening and why does it matter?

A hardened home is built and maintained to withstand risks posed by natural disasters such as earthquakes, floods, hurricanes, and wildfires - the steps taken to harden a home vary based on the relevant risk. For example, foundation strapping helps prevent earthquake damage while doing nothing to prevent flood damage.

When it comes to wildfires, hardening a home requires construction materials that are less likely to ignite and burn — even if they’re exposed to embers or flames — and a well-maintained space surrounding the dwelling. Many homeowners may think flame spread is the biggest risk, but fire scientists maintain that most wildfire-caused house fires in the wildland-urban interface (WUI) ignite from embers,1 making a hardened home especially important.

Firefighters fighting a wildfire burning a homeHardening homes in the wildland-urban interface can help
prevent the spread of wildfires.

The Wildland-Urban Interface: Wildfire Risk at Your Doorstep


In 2008, California strengthened its building codes to require ignition-resistant building materials for new construction in fire-prone areas.2 In a study analyzing fire damage during the 2018 Camp Fire, a blaze that destroyed almost 19,000 buildings in and around Paradise, CA,3 the benefits of ignition-resistant building materials become apparent.

During the course of the fire, almost 10,000 single-family homes were destroyed and 465 damaged. For single-family homes, the ignition-resistant building materials made a striking difference: 79.0% of homes built before 2008 were destroyed or suffered major damage compared to 40.6% of homes built in 2008 or later. Indeed, slightly more than half (50.6%) of homes built in 2008 or later had no damage, whereas only 17.7% of homes built before 2008 escaped damage.

10 deadliest fires in California history infographic

Download this infographic

What parts of a home can be made ignition resistant?

Homes can be made with a variety of materials, all of which fall into one of three categories: combustible, ignition-resistant, and noncombustible. Examples of each material type include:

Combustible: solid wood, wood-based composite materials, and plastic or plastic composite materials.
Ignition-resistant: lumber treated with fire-retardant chemical and rated — based on standards’ groups testing — for outdoor use.
Non-combustible: metal (excluding aluminum) and traditional three-coat stucco.4

Ignition-resistant or non-combustible materials are available for many parts of a home, including the roof, gutters, siding, decking, and fencing. Other building materials that can further protect homes include:

Multi-pane, tempered-glass windows resist breaking even in high radiant heat conditions, keeping embers out.
Attic, roof, and foundation vents designed to screen out embers reduce the risk of a spot fire.

A couple surveys homes burned by a wildfireHardened homes are less likely to be destroyed by a wildfire.

Embers, Wind, and Fire: A Dangerous Mix

Find out more about ignition-resistant and non-combustible building materials from this Insurance Institute for Business and Home Safety (IBHS) guide. If you have customers in California, the IBHS has a PDF with additional, detailed information they can use to build or retrofit their home for wildfire resistance.

Remember, to effectively protect a home from wildfire damage, residents must regularly maintain these materials and, when needed, replace them.

The role of effective building codes

The California building codes implemented in 2008 set specific requirements about which type of material can be used to build certain parts of a home in fire-prone areas. Siding, for example, must be non-combustible or ignition-resistant. If it is made of combustible material, the product must pass a fire-resistance test.

In 2018, Washington state strengthened the building codes local governments must adopt for the construction of homes in the WUI. Some local jurisdictions have even adopted codes beyond what the state requires.5

Creating and maintaining space around your home

The study described above looked only at building codes and the building materials those codes required, which explains just one aspect of why some homes survived the Camp Fire and others did not. Two other major factors influencing the chances a home will survive a wildfire are the maintenance of the home and the area surrounding it.

Consider a home built with ignition-resistant materials but covered with combustible materials, such as dried leaves, or with combustible landscaping around the home. Embers landing on such a home have a greater chance of starting a spot fire than embers landing on a home without them.

Similarly, flames and radiant heat are less likely to reach a home with properly maintained space around it. The maintained space around the home, sometimes called defensible space, can be seen as the home ignition zone. The National Fire Protection Association (NFPA)’s zone system makes this concept easy to understand.

The Immediate Zone – the area most vulnerable to embers. This zone covers the area within 5ft of the home’s furthest attached exterior point. Nothing combustible should be in this zone, meaning no propane tanks, firewood, flammable plants, furniture, needles in gutters, landscaping bark or anything similar.
The Intermediate Zone – the area that covers between 5ft and 30ft from the home’s furthest attached exterior point. In this area, landscaping should be carefully chosen and maintained to reduce fire spread.
The Extended Zone – the area covering from 30ft to 200ft from the home. This zone should contain landscaping designed to interrupt the fire’s path and keep any flames that do occur small and on the ground.

Perimeter map fire danger 2Find specific details about how to protect your home in
NFPA’s guide to preparing homes for wildfire.


How the Growing Wildland-Urban Interface Increases Property Risk


The importance of community action

To effectively protect any home in a wildfire-prone community, homeowners must work together to protect each other’s homes.

Consider this scenario: a fire-prone area with only a moderate amount of space between homes, meaning each home’s Intermediate Zone overlaps with its neighbor’s. In a situation like this one, homeowners must work with each other to create and maintain their zones.

As it turns out, scenarios like this are relatively common throughout Washington state. Towns like Leavenworth, Cashmere, Soap Lake, Prosser, Wenatchee, and Roslyn have all seen wildfire nearby and all include developed areas with homes in close proximity to each other.

The NFPA’s Firewise USA program helps community members take action together to protect their homes from wildfire risk.

Next steps

Though wildfires increasingly seem like an inevitability, there are proactive steps that can be taken to limit property loss.

In conjunction with national and regional efforts to curb the size and scope of future wildfires, individual actions like home hardening and routine maintenance can make a world of difference. Use our resources to educate your customers and help them keep their homes safe.

More wildfire content

[1] Smithsonian Magazine: https://www.smithsonianmag.com/science-nature/untangling-physics-firenadoes-drifting-embers-other-wildfire-phenomena-180971735/

[2] Wikipedia, https://en.wikipedia.org/wiki/Camp_Fire_(2018) 

[3] Sacramento Bee, https://www.sacbee.com/news/california/fires/article227665284.html 

[4] Insurance Institute for Business & Home Safety, https://disastersafety.org/wp-content/uploads/2019/03/Wildfire-Retrofit-Guide-California_IBHS.pdf

[5] Seattle Times, https://www.seattletimes.com/seattle-news/urban-wildfire-when-homes-are-the-fuel-for-a-runaway-blaze-how-do-you-rebuild-a-safer-community/ 

Robert Ferrell, P.E. is WSRB’s Vice President of Public Protection. He leads the team that manages the insurance rating of cities, fire districts and building departments throughout Washington state. He has more than 25 years of experience in fire insurance rating.

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