Defensible space refers to the area surrounding a building that is mitigated to protect it from wildfires. Along with the quality of a building’s roofing material, adequate defensible space is one of the most important factors in determining a building’s ability to survive a wildfire. Homeowners should be aware of conditions that may compromise the defensible space of their home, especially in fire prone regions such as North Idaho.
The size requirements for defensible space vary by jurisdiction because the potential for wildfires varies by region. Buildings in forested areas of the Southwest need a much larger protective space than in New Jersey, for instance. As of 2006, California state law mandates a minimum of 100 feet of defensible space for houses in rural locations. Trees and shrubs surrounding a house should be trimmed and spaced apart a safe distance from one another. Chainsaws can be used to remove trees and branches, pruning shears to trim plants, and rakes for removing pine needles and other ground-level combustibles. Trees that are very close to the house should be removed because this is where fire-prevention is most critical. Vegetation can be plentiful towards the perimeter of the space if it is green and pruned.
In summary, buildings can be spared from wildfire damage through the removal of surrounding flammable vegetation. Defensible spaces are critical in hot, dry, forested regions, although their presence is recommended everywhere.
Portions of this article originally appeared on nachi.org and are authored by Nick Gromicko and Kenton Shepard. They are used with permission from the International Association of Certified Home Inspectors.