When last week’s fires in Los Angeles set parts of the city ablaze, one viral image was of a lone house in Pacific Palisades that was left standing while all of the homes around it were destroyed.
Architect Greg Chasen said luck was the main factor in the home’s survival, but the brand-new build had some design features that also helped: a vegetation-free zone around the yard fenced off by a solid concrete perimeter wall, a metal roof with a fire-resistant underlayment, class A wood and a front-gabled design without multiple roof lines.
Elsewhere in the Westside Los Angeles neighborhood, another home with a metal roof, cement design and a covered chimney appeared in excellent condition while the homes all around it were all lost. “This house was perfect; it was built for this,” Jacob Ruano, a federal firefighter with the US Forest Service who was deployed to fight the Palisades fire, said. “Not all homes are built like that.”
About 12,000 houses, businesses and other structures have been lost in the recent raging wildfires and Angelenos are quickly learning that the architectural and design choices people make plays into the level of damage fire can cause to their structures, making some homes more prone to burning down while others appear completely fire-resilient.
Even as wildfires in the US west grow more frequent and severe, aided in part by global heating, more people than ever are moving into high-risk areas. At least 44 million homes in the US reside in the wildland urban interface (WUI), where houses mingle with the forest. People live in the WUI (pronounced woo-eee) for all kinds of reasons, from a desire to be close to nature to lower housing prices.
“Many southern California homes are inherently vulnerable due to their exterior materials and vegetated surroundings,” said architect Duan Tran, a partner at KAA Design Group in Los Angeles. “When clients talk to us about their dream homes, there’s often a note of worry; they’re asking how to make their homes not only beautiful and functional, but also safer in an unpredictable future.”
That means telling clients that siding, overhangs and decks, common features to increase a home’s warmth and charm, can ignite easily. Wood or shingle roofs are high-risk, as are homes with open vents and eaves, since flying embers can enter a home through them.
While no structure is entirely immune to the kind of devastating wildfires we’ve seen in Los Angeles, architects can make their projects more resilient, which allows for valuable extra time when it comes to evacuation and firefighting efforts. Materials such as concrete, stucco and steel can significantly reduce a home’s vulnerability and builders can use noncombustible materials for the part of a fence that connects to the house to prevent spread.
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Researchers who studied structure loss in California wildfires from 2013 to 2018 found that enclosed eaves, vent screens and multi-pane windows have all been proven to prevent wind-born embers from penetrating a house. While sprinklers may not be able to stop an enormous wildfire, fire suppression systems can slow a fire’s progress.
“As we’ve seen in LA and with the Marshall fire and Camp fire and Lahaina fire, what truly characterizes the process of a home burning down, is largely the result of embers that fly miles ahead of that wildfire,” said Kimiko Barrett, a wildlife researcher at the non-profit Headwater Economics. “They account for 90% of structural loss in a wildfire.”
California already has some of the strictest building rules, colloquially known as Chapter 7A, when it comes to new homes in high-risk fire regions and they’re designed to improve a house’s chance of survival. While regulations and building codes are effective, they don’t apply to homes built before 2008, when Chapter 7A was adopted. This means that even homes designed to withstand fire are vulnerable when wildfires spread to older homes nearby.
Houses made from chemically-treated synthetic materials, which have become common since the 1980s, are especially vulnerable since the home itself acts as fuel for a fire, as do the many petroleum-based products inside, ranging from furniture and carpet to appliances and electronics. Once they start to burn, the energy release becomes so intense that homes release radiant heat and in a high-wind scenario, propagate structure-to-structure spread.
Aside from building materials, another way to protect your home is through collective action. “If just one or two neighbors are protecting their structures and reducing the flammability of their property, it’s not as effective as when a group of people are working together,” said research ecologist Alexandra Syphard, who studies wildfires. “The defensible space right next to your structure can provide the best protection.”
When it comes to that defensible space, the buffer area between your home and the surrounding area, Cal Fire, the state’s department of forest and fire protection, says there are simple and low-cost steps everyone can take. Best practices include clearing dry vegetation, replacing mulch within 5ft of all structures with noncombustible dirt, stone or gravel and regularly cleaning roofs, gutters, decks and the base of walls to avoid accumulating fallen leaves and other flammable materials.
For the millions of homeowners who aren’t building a house from scratch or can’t afford a pricey full-blown retrofit, there are basic, affordable measures that can be taken for as little as $2,000 such as installing metal gutter guards and enclosing under-deck areas with metal mesh screening. And strategies such as closing a fireplace flue during wildfire season and relocating firewood at least 30ft from your home can be done at no cost. “Doing something is better than nothing,” said Syphard.
There is currently no federal agency or any funding available to help people harden their homes or reduce risk to the built environment.
While architecture, design and defensible space efforts all come into play for resiliency, fire ecologists say where you build your house is the primary factor in determining whether it will burn. “Folks say we could have prevented this, we could have just hardened the homes,” said Syphard. “There are lots of examples of homes that have done everything right, but when you’re fighting millions of wind-borne embers that are flying through gusts of 70-mile per hour winds, it’s hard to keep one from going underneath your garage door.”
Gabrielle Canon contributed reporting