GBA reader “Mojave Disaster” is asking a question that many others in the far West are confronting these days: Which building materials offer the greatest protection against wildfires?
In a post originally published nearly two years ago and updated just recently, Mojave writes, “As you may have heard, there have been some fires of greater speed and intensity than normal going on lately.” Unfortunately, the same words could have been written just this year, as residents of California, Washington, and Oregon coped with an onslaught of wildfires. Some problems just don’t go away.
Mojave is getting ready to build a superinsulated home with double-stud exterior walls. “What inexpensive, time-tested materials, and how thick, must I put to the exterior to have any chance of the house surviving the heat of a fire tornado?” Mojave asks. “Since there’s also the issue of soil liquefaction in this seismic zone, I hope the answer isn’t a massively thick concrete bunker.”
Windows and doors are another issue. Is there anything available in big-box outlets that would work?
Those are the questions for this Q&A Spotlight.
Let concrete and steel be your friends, suggests Peter L.
“Exposed exterior wood is not a good idea,” he adds. “My recommendations would be an ICF [insulated concrete form] home with 6-in. concrete and rebar, and then use synthetic, non-flammable stucco like StuccoMax for the exterior walls.”
A steel roof also would help, as would paying very close attention to any venting details so that burning embers can’t get into the building.
Finally, Peter says, create a “defensible space” around the building that is free of trees and shrubs that could become fuel for an approaching fire. This vegetation-free zone should extend 30 to 50 ft. from the building.
“The above will give you the…