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,” said Jacob Ruano, a federal firefighter with the US Forest Service who was deployed to fight the Palisades fire. “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 44m 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.
video of burned down homes before panning over to a home unscathed
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 Headwaters 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
