I have written numerous critiques of the current fire policies that primarily focus on hinterland fuel reduction by logging and prescribed burning. While some limited use of these strategies has a place in reducing fire risk to homes, the main emphasis should be on the house and surroundings.
The most significant home losses are not due to wildfires in the forest but due to urban fires. Firefighters are overwhelmed once numerous homes are ignited, and house-to-house fires continue in a domino effect.
However, what are the primary areas or ways that homeowners can “harden” their property to improve the chances that their homes will survive a wildfire?
People must first recognize that most structures ignite from embers, not a wall of flames as we often imagine. This video, which features fire researcher Jack Cohen, is worth watching.
Second, radiant heat ignites homes, with the heat from a neighbor’s home causing the ignition of adjacent homes. A burning home puts out far more “radiant” heat than a wind-driven wildfire. Wildfires may indeed have high temperatures, but they usually only last for a short time in any one place before the wind pushes the flames and heat to a new location.
This home near Lake Tahoe is a waiting time bomb. There is no defensible space. Trees and shrub vegetation nearly smother the home. The wooden deck is likely to be one of the factors that a fire will ignite, eventually burning down the rest of the home. Photo by George Wuerthner
However, if a home is burning, it pushes out more heat for an extended period of time, plus the construction of materials in a typical home includes flammable substances.
Logging and prescribed burns in the hinterlands do nothing to reduce wind-blown embers or radiant heat.
DEFENSIBLE SPACE
The first thing a homeowner can do is create defensible space. Usually, this means reducing or eliminating flammable brush, grasses, and trees adjacent to within five feet of a home. Have a five-foot margin of gravel, cement, or other non-flammable materials. Clearing these fuels 30 feet or so from the house is typically sufficient. Clearance of more than 100 feet usually provides no further protection. It’s essential to note that clearing trees and shrubs doesn’t necessarily mean you must eliminate all of these plants. For instance, one can trim lower branches on boles, but one doesn’t need to remove entire trees.
ROOF AND GUTTERS
A non-flammable roof can save a home. I’ve read that a metal roof alone might protect most homes, but there are other non-flammable materials, like tile roofs, typical of many California homes, and fire-resistant shingles.
Gutters collect debris like pine needles, leaves, and other flammable materials. One can get metal screens that fit on gutters and allow water to drip through, but keep debris from collecting in them.
EAVES
Many homes are constructed with eaves with vents where the wind can drive embers into the house’s interior. Sealing all gaps and covering vents is critical. Eaves can also be coated with a fire-resistant spray.
VENTS
Wind-blown embers often gain entry into a home through vents. Screening vents with fine mesh that precludes entry of embers is critical. Such mesh covers are inexpensive. Alternative vent covers can be installed that close entirely if heat is detected.
With vents, one should also consider doggy doors. Such exits are designed to swing open easily, and in high winds, they are a ready entry pathway for embers. Installing a means of locking the door can save your house.
DOORS AND GARAGES
Wind-blown embers can easily penetrate homes through gaps in poorly-fitted doors, or around the edges of weather-stripping. For example, my garage door does not fit tightly to the floor, and there are minor gaps. Fixing these gaps is critical to preventing home ignition.
DECKS AND STEPS
Many homes have decks and steps under which flammable material can be collected. Burning decks, in particular, is often how a fire starts that ultimately ignites the home. Cleaning materials from under these structures is critical. Decorative cement planks can replace wooden steps and decks.
WINDOWS
Double to triple-resistant windows are another relatively inexpensive means of reducing entry into the home. One weak link of windows is the frame. Many are made from vinyl and can melt in a fire. Metal frames (not aluminum, which have a low melting point) can fix this problem.
FENCES
Wooden fences are often attached to the home. These tend to dry out over time, are very flammable, and can ignite the home. Short of replacing the entire fence, substituting metal fencing for the last 4–6 feet of any segment that is attached to the house can preclude ignitions.
ROOFTOP SPRINKLERS
A wet house won’t burn. There are inexpensive rooftop sprinklers (like the ones used on lawns) designed to sit on the crest of a roof. Adding sprinklers that water the sides of a home can improve its fire resistance further.
The only cautionary remark I would make is that sometimes the electricity goes off either because power poles have burned, or power companies turn off the electricity to avoid new ignitions. If your water system relies on electricity to pump the water, sprinklers may not be effective. My water system is gravity feed pressure due to piping from a mountain source, and it is likely to be available even if the power is unavailable.
Another issue is that water systems can become overwhelmed. Most municipal water systems are not designed to handle thousands of homes using water simultaneously, which was one of the issues surrounding the Pacific Palisades fire in California.
There are also much more effective sprinkler systems that can be installed and activated by Wi-Fi, so if you were on vacation and learned that a fire was approaching your home, you could start the sprinklers. Although these are expensive, they are still a cost-effective option compared to the cost of replacing a home.
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