Peter and Sharen McColl watched helplessly from a nearby roadway as a 100-foot wall of fire swept over their newly built home and horse stables. A few hours earlier, a 4 mile-wide finger of the Cedar Fire had swept across Interstate 8, the multilane freeway connecting southernmost California with Arizona. The fire would stop its push southward only a few more miles past their home.
When the McColls selected the home site—located on a mountain top 1,000 feet above Harbison Canyon, a small community 15 miles east of San Diego—they knew it lay in harm’s way. The sides of the mountain were covered with thick, dry chaparral, and they had decided to leave undisturbed the vegetation that grew among large boulders located only a few feet from their dwelling.
However, although their home was in a more vulnerable position, it survived while over half of those located below in Harbison Canyon were destroyed. The McColls clearly had luck on their side, but they had also made good decisions about how to build their home to withstand the potential threat of a firestorm. These included integrating construction features that met or exceeded those contained in the International Urban-Wildland Interface Code™ (IUWIC™) for structures required to be of Class 1 Ignition-Resistant Construction (see Table 2).
Concrete masonry was selected for the exterior walls of both the home and the stable, and the roofing of each structure was concrete roof tile. The horse stable was constructed without an eave, where an intense fire exposure might have caused ignition; and the combustible wood framing of the house eaves, including the fascia board, were covered with cement-based stucco. Among other features required by the IUWIC, the dwelling’s windows had double-pane glazing.
There are a number of guides for homeowners who plan to build or retrofit dwellings in urban-wildland interface areas. Such information is important for the education of local citizenry, who are unlikely to read or fully understand why certain building regulations are necessary. A pamphlet published by the Institute for Business & Home Safety (IBHS), “Is Your Home Protected from Wildfire Disasters? A Homeowners Guide to Retrofit,” is particularly worthwhile. It provides basic information in simple-to-understand language.
As an example, it explains that structures constructed on sloping properties, like the McColl home site, are particularly at risk because “hot gases rise in front of the fire along the slope face, pre-heating the up-slope vegetation, moving a grass fire up to four times faster with flames twice as long as fire on level ground.” The photo shown here gives some idea of how hot the fire was. Since the McColl’s buildings were still rather new when the fire occurred, unused materials, such as these concrete masonry units, remained on the property. They had been stored on wooden pallets, which were incinerated by the intense heat. The only evidence remaining of the pallets is the charred ashes of a few boards. The brochure also provides three checklists of critical steps that should be taken before, during and after a wildfire strikes.
For more information, visit Insurance Institute for Business & Home Safety (IBHS).
Photos courtesy of Chris Hastings, RCP Block & Brick Inc, Lemon Grove, California.