California’s wildfire building code significantly reduces structural loss

A recently released study by the National Bureau of Economic Research found that California’s building code for higher risk wildfire areas has significantly reduced structural loss.

A home built in 2008 or later under the Golden State’s expanded wildfire building code is about 40% less likely to be destroyed than a 1990 home experiencing an identical wildfire, according to the research. “There is strong evidence that these effects are due to state and local building code changes,” the bureau’s report says.

California now requires all roof material in wildfire hazard areas to be rated Class A for fire resistance. In addition, exterior siding must be fire resistant, vents must covered by a fine wire mesh to resist ember intrusion, windows and doors must resist fire for at least

20 minutes, and decks and other building appendages must be built of non-combustible materials. The most recently update code also includes requirements for defensible space.

Other states that have experienced damaging large-scale wildfires including Arizona, Colorado, Oregon, and Washington have not as yet followed California’s lead to beef up building codes. California’s code, research suggests, presents a useful model for others to follow.