The Quest to Build Wildfire Resistant Homes

“We have to get over this idea that it’s always the best thing to evacuate,” Kolden says. “We used to have community bomb shelters, didn’t we? They are functionally community fire shelters. Those are the kinds of conversations we haven’t had. And if we really want to build fire-resistant communities, we have to move them forward. »

Our shelters

The basic science to keep a building from burning isn’t particularly high tech or expensive, but it does run counter to the way we’ve long thought about wildfires. In the 1970s, when Jack Cohen pioneered the concept of “defensible space,” an area cleared of flammable vegetation or other combustibles around a structure, the U.S. Forest Service largely ignored him. It was a paradigm-shifting innovation—a retrofit that was easy to implement, at least wherever space was available—but it meant viewing wildfires in a defensive position instead of the offensive position that the Forest Service adopted for nearly 100 years.

Today, regulators have arrived and California building standards for high and very high wildfire hazard areas now require 100 feet of open space around structures, at least where there is 100 feet available at to clean. Other home reinforcement measures are comparatively small-scale, even cheap: replacing flammable roofs, sealing window seams and junctions, using fine wire mesh to cover vents where sparks could enter. And the latest fire-resistant materials won’t save a home where the gutters have been allowed to fill with dry kindling. Form tends to follow function: flat roofs, steel windows, clean lines that leave no refuge for a wandering ember. Each devastating fire is bound to encourage new innovation as new weaknesses are revealed.

The basic science to keep a building from burning isn’t particularly high tech or expensive, but it does run counter to the way we’ve long thought about wildfires.

California’s strictest fire code applies only to homes located in a clearly designated high-risk area (where, according to the California Department of Forestry and Fire Prevention, approximately one in four residential structures found) – and only to those that are newly built. In paradise, where a 2018 fire killed at least 85 people and destroyed more than 18,000 structures, nearly 40% of homes built after 1996 survived, compared to just 11% of those built before.

The gradual addition of increasingly dense housing in flammable dead-end canyons is a concern, says Thomas Cova, an evacuation researcher and professor of geography at the University of Utah. The space between the houses, or its absence, is a significant indicator of whether they are burning or not. Building suburban infill is in many ways good housing policy for a state with a severe lack of affordable housing, but it’s bad land use policy for a state with intense wildfires and recurring. Yet there are few clear incentives for local authorities to prevent the construction of new homes, even those that will increase the risk to the wider community. One more flammable structure on the hillside, one or two more cars on the road, but also revenue from one more property tax bill.

Extensive renovation of the built environment in towns and cities established nearly a century ago is essentially irrelevant – it is work that is not required by state codes, and no clear source of funding is available. Even where communities are wiped out by fire, existing roads fall short of minimum fire regulations when it comes time to rebuild. But completely new developments are held to much higher standards.

“I always thought of shelter-in-place as an emergency backup plan, and it would be really wise to consider what options you might have,” says Cova. “But now I think it also comes into the discussion associated with (new) development.”

This is especially true in light of California’s acute housing affordability crisis, which has put great pressure on the state to not only keep building new homes, but also to build them on cheaper land. , more rural and more at risk of fire. A new directive issued in October 2022 by the California State Attorney General explicitly calls on local agencies to “avoid over-reliance on community evacuation plans” and consider shelter-in-place options.