Back-to-back breakout of summer wildfires turns attention to making fire-resistant homes
This summer’s back-to-back breakout of wildfires in the North State has put the spotlight on what it takes to make homes fire-resistant.
The massive Carr Fire ripped through the area in July, destroying 260 homes in the city of Redding and another 817 residences located in western Shasta County.
While experts agree that no building upgrades could have fully protected homes from the fury of that swift-moving inferno, installing fire-resistant features still makes sense, according to Redding-based Nichols, Melburg & Rossetto Architects + Engineers.
A recent consumer alert from NMR outlines steps homeowners can keep in mind if they are rebuilding from scratch or are considering upgrades to their existing homes.
"A wildfire ... will attack your home from the exterior. Driven by strong winds, it will reach peak temperatures in seconds and may pass over your site and be gone within minutes, as soon as all the standing fuel is consumed,” NMR's alert said.
“The problem then is secondary spot fires started on and within your home by wind-driven flames and embers. If you can design your home to withstand this massive but brief exterior attack, it has a good chance of survival,” said the alert.
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One protection measure is a state building code that requires all new homes to be equipped with fire sprinklers. While those systems cannot stop a Carr Fire-sized blaze from destroying a house, fire sprinklers may extinguish flames that break out inside a home and keep them from spreading to nearby vegetation and causing a wildfire that way, said Jim Wright, building official for the city of Redding. "That’s a good prevention issue."
In the wake of the region’s devastating wildfires, more building regulations are likely coming, NMR Principal Architect Les Melburg said.
“I can almost guarantee you that ... as the result of this Carr Fire, when they do the forensics on it and find how the fire managed to spread and what the issues were, there will probably be some new recommendations or code issues,” Melburg said.
It’s not yet known how many of the nearly 1,100 homeowners who lost property in the Carr Fire intend to rebuild. But the replacement homes of those who are — and who live an area that state officials deem wildfire-prone — are required to include several features that are designed to make it harder for fire to overtake a residence.
Those features include using building materials and window types that are more fire-resistant. Other features include using roof systems that are able to stop hot embers and flames from taking hold.
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These standards only apply to homes that are built within California’s “Wildlife-Urban Interface” or WUI for short. That’s a fancy term for areas that are located near undeveloped wild lands.
Sometimes people don’t realize that homes that don’t directly connect with open space can still be at high risk, said Melburg.
“The WUI boundary can actually project hundreds of feet into a subdivision, so people would be surprised to find how far they are away from a true greenbelt or wildlife zone and still these [building requirements] will apply,” he said.
Also, Wright said homes located outside areas that are officially designated as high-fire zones could still benefit from incorporating the WUI building standards. Those generally involve upgrades to windows, roofs and materials used on the home’s exterior to reduce flammability.
Having a home that’s located outside the official high fire area “does not mean that you won’t have shrubs outside of your house that catch fire," added Wright. "Certainly, anybody who is remodeling now could incorporate those [features]. It certainly wouldn’t hurt.”
Here are some highlights of strategies to make a home more fire resistant.
Make roof upgrades
Vents on the roof can become an entry point to your home for hot embers and flames. Embers can 'rain' on and around homes for hours before and after actual wildfire flames reach the house, according to the Division of Agricultural and Natural Resources at the University of California.
Cover all vent openings with 1/8-inch to 1/4-inch metal mesh, the California Department of Forestry and Fire Protection recommends. Don’t use fiberglass or plastic mesh, which can melt and burn. Protect vents in eaves or cornices with baffles to block embers, Cal Fire suggests.
In some new construction, vents located underneath eaves have been eliminated. In their place, the vent function is performed by through-roof vents located in the lower region of the roof, especially near the roof's edge.
Install tempered glass
While a home’s exterior might be able to withstand flames, searing heat can shatter regular, non-tempered glass and let flames inside.
Tempered glass stands up better to intense heat.
In addition, NMR suggests, "fold-down panels or shutters on sloped rails can also be designed to close and latch automatically. For non-operable windows, there are many
kinds of wire glass or fire safety glass that holds together even though cracked by the heat. These are good alternatives to plastic bubble skylights."
Aggressively control trees and shrubs near the home
California law already requires homeowners clear flammable vegetation within 30 feet of buildings and modify vegetation within 100 feet around buildings to create room for firefighters to maneuver. Consider trimming low tree branches that could serve as “ladders” for flames, the University of California says. And space trees and plants to make it harder for flames to spread, says the group.
NMR suggest using “incombustible material between you and the wild lands using patios, driveways, or low-growing fire-retardant plants. You can be attacked from any direction, but an up-slope running fire is by far the most dangerous and so deserves special design attention.”
For more information visit the Cal Fire resources online at https://bit.ly/29FWGE1 or the University of California's guide for homeowners to reduce the wildfire risk at https://bit.ly/2GrGG8j.
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