New houses, built to fire code, burned down anyway in California’s 2017 Thomas Fire

Many of the homes destroyed on Andorra Lane were ignited by embers, not by walls of flame, experts say. (Photo by Morgan Lieberman/KPCC)

LOS ANGELES – California’s building codes are not keeping up with the severe, wind-driven wildfires that are becoming the norm.

Ten years ago, the state passed strict new standards for homes built in high fire-risk areas. But even homes built to those standards were destroyed in the Thomas Fire in December 2017. Homes now are being rebuilt in the same places, under the same codes.

In the Ventura Foothills, about an hour northwest of Malibu, four of the nine homes on Andorra Lane burned down in the Thomas Fire. Almost no one expected it. After all, the homes were brand new. They were surrounded by dozens of other homes. And most important, they met the state’s building codes for areas at heightened risk of wildfires.

Nancy Bohman, who lives in one of the Andorra Lane homes that survived the fire, said she was “totally shocked. Totally blown away, ’cause look,” she said, slapping the sturdy outside wall of her house. “It’s stucco and a concrete roof.”

Very high fire-hazard zones

“Almost no one” expected homes on Andorra Lane to burn down, but Cal Fire did.

Andorra Lane is tucked into a fold of the foothills above Ventura, and the entire nine-home subdivision is in a “very high fire hazard severity zone.” That’s a technical term created by Cal Fire – the state’s Department of Forestry and Fire Protection – and it applies to neighborhoods on the edge of undeveloped land, “the wildland urban interface” where severe wildfires are likely. That area is also known as the WUI for wild urban interface.

The term is important because, since 2008, all homes built in these zones have had to meet strict building codes designed to prevent them from catching fire. They must have fire resistant roofs and siding; fine mesh screen on attic vents to keep embers out; decks and patios made of non-flammable material, and heat-resistant windows.

Built in 2016, the houses on Andorra Lane had all those features. They were supposed to have a better chance of surviving a wildfire than older homes without those protective features.

Where you build your home is more important than what materials you build it from, says fire ecologist Alexandra Syphard with the Conservation Biology Institute. (Photo by Morgan Lieberman/KPCC)

“Nobody ever reads the fine print”

When the first residents of Andorra Lane moved into their houses in 2016 and ’17, few realized their homes were in a risky place. But buried in their closing documents was a small disclosure, telling them they were moving into a “very high fire-hazard severity zone.”

“We flipped through hundreds of pages; I’m sure nobody ever reads the fine print,” said Phil Azer, one of the four burned-out homeowners on Andorra Lane. “I think I was probably more concerned about earthquakes.”

His neighbors had similar experiences: Only one recalled seeing the fine print.

“I don’t think (the real estate agent) ever actually said, ‘Hey, do you realize you’re on a flood or fire zone,’ or anything like that?” Bohman asked.

The developer, Williams Homes, declined to comment.

Why did the houses burn?

Ventura City Fire Marshal Joe Morelli thinks topography played a role. The narrow valley in which Andorra Lane sits may have acted as a wind tunnel, funneling embers toward the neighborhood.

“Really what we had was something like a blowtorch going through our city,” Morelli said. “And even with the fire-resistant construction standards, you can still have loss. They’re not fireproof standards.”

Researchers who study how houses burn say embers are to blame, not walls of flame.

When embers land on ornamental mulch, pine needles built up at the base of a wall or wooden deck furniture, they smolder. And those little fires can eventually ignite the house itself, even a fire-resistant house, especially if no one is there to put them out, as is usually the case in an evacuation zone during a mega-fire.

California wildland fire codes may also have weaknesses, Morelli said. They don’t cover wooden sheds, carports or backyard play structures, which can ignite, sending embers toward the house. Nor do they cover skylights that open outward. And garage doors aren’t as fire-resistant as they could be, meaning embers can get sucked underneath them, igniting whatever is inside.

Being new, the houses on Andorra Lane were likely some of the most fire-resistant in Ventura. But many of the older houses that burned in the Thomas Fire also had some fire-resistant features.

According to Cal Fire data, 80 percent of houses destroyed in the Thomas Fire had fire-resistant exteriors and 90 percent had fire-resistant roofs.

It’s where you build, not what you build with

To fire ecologist Alexandra Syphard with the Conservation Biology Institute, it’s becoming increasingly clear that houses built in risky places are impossible to fireproof.

“You can make a big difference in increasing the potential safety of your house, but you can’t guarantee that it’s not going to burn,” she said.

Her research has found that where you build your house, not what it’s made of, is the biggest factor in determining whether it will burn.

But city and state officials are reluctant to do anything that would increase the cost of new housing. Yolanda Bundy, the chief building official with the city of Ventura, said she’s just not focused on changing local building codes or overhauling land use planning at the moment.

“Right now, all the efforts are concentrated on helping people rebuild their homes, not to create more rules or regulations or more processes,” she told KPCC earlier this year.

The burned homes in “very high fire-hazards severity zones” will be rebuilt according to the newest codes, which Bundy still considers a big improvement because nearly all 777 of them were constructed before 2008.

Statewide, new building codes are adopted every three years. That means lessons learned from the 2017 Thomas Fire will not be incorporated into the next round of code changes.

“We’re constantly playing catch up,” said Pete Muñoa, Cal Fire’s deputy chief of land use planning. “We’re trying to be proactive to see how we can make homes more survivable by adding additional code requirements.”

But, he said, regulators also have to balance safety with cost.

“Depending on the pushback we get from industry, we may or may not be successful in getting codes that we believe are going to be effective.”

What you can do

So, what should you do if you live in a high fire risk area, or are rebuilding your house in one? Focus on the area 30 feet around your house, said Tom Welle with the National Fire Protection Association.

The first 5 feet out from your foundation should be nearly bare, or only covered with non-flammable plants or landscaping. Beyond that, Welle said to “think about where leaves and debris just pile up because of wind. That’s where embers are going to go.”

Keeping your house from igniting is really important, Morellis said, because nearly 90 percent of houses that ignite, even brand new ones, are destroyed.

This story is part of Elemental: Covering Sustainability, a multimedia collaboration between Cronkite News, Arizona PBS, KJZZ, KPCC, Rocky Mountain PBS and PBS SoCal.