Home Hardening & Defensible Space
Wildfires are becoming more frequent and more intense across California and the western U.S. Over the last several decades, climate change has resulted in higher year-long temperatures and increasingly dry weather conditions in California. Extended, multi-year droughts, higher temperatures during dry seasons, and longer wildfire seasons throughout the year have contributed to excessive amounts of wildfire fuel in the form of dry or decayed vegetation. Since 1986, wildfires in the western United States have occurred nearly four times more often, burning more than six times the land area and lasting almost five times as long. Through the end of the 2017 calendar year, 11 of the 20 most destructive wildfires in California have occurred in the last 10 years. The 2018 calendar year witnessed the most destructive wildfires in California history in terms of the loss of life and structures.
AB-38, a California law that was enacted in 2019, requires sellers of residential properties in designated High or Very High Fire Hazard Severity Zones to provide buyers with a defensible space inspection report, demonstrating compliance with local defensible space standards, prior to the close of escrow.
Two of the most effective strategies for protecting your home are home hardening and defensible space. “Home hardening” means upgrading or maintaining your home so it is less vulnerable to embers, heat, and flames. “Defensible space” refers to the buffer zone around buildings that reduces fire risk by managing vegetation and other fire fuels. Together, these steps can dramatically increase the chances of your home surviving a wildfire.
Examples of Home Hardening
Roofing: Use Class A fire-rated roofing materials (metal, clay tile, composition shingles).
Vents: Cover attic and crawlspace vents with 1/8-inch metal mesh to block embers.
Windows & Doors: Install dual-pane or tempered glass windows; ensure weatherstripping seals gaps.
Siding: Use non-combustible or ignition-resistant materials (stucco, fiber-cement, brick).
Decks & Fences: Replace wood near the home with fire-resistant materials; keep the underside of decks clear.
Rain Gutters: Keep them free of leaves and debris to prevent ember ignition.
Creating Defensible Space
Defensible space is the buffer you create between your home and grass, trees, shrubs, or other fuels. In California, state law (PRC §4291) requires up to 100 feet of defensible space around homes in fire-prone areas. Three zones to manage:
Immediate Zone (0–5 feet):
Remove all combustible materials (wood piles, mulch, patio furniture).
Use hardscaping (gravel, pavers) instead of plants.
Keep roofs and decks clear of debris.
Intermediate Zone (5–30 feet):
Space trees at least 10 feet apart.
Keep grass trimmed to 4 inches or less.
Prune branches up to 6 feet from the ground.
Extended Zone (30–100 feet):
Create horizontal and vertical spacing between trees and shrubs.
Remove dead plants, leaves, and pine needles.
Thin dense vegetation to slow fire spread.
Action Steps for Homeowners
Walk your property each season and look for fire risks.
Schedule a defensible space inspection with your local fire department if available.
Keep records of your home hardening improvements—these can help with insurance and real estate transactions.
Start small: even clearing gutters or trimming vegetation can make a big difference.
Consider the following home hardening strategies for every area of your property:
Roofs
Material choice: The roof is the most vulnerable part of your home. Homes with wood shingle roofs are at high risk of being destroyed during a wildfire. Opt for composite, asphalt, metal, clay, or tile roofing to resist fires.
Ember sealing: Close off gaps under roof tiles and shingles to block wind-blown embers.
Debris removal: Regularly clear leaves, pine needles, and other debris from the roof to prevent ignition.
Chimneys
Chimney screening: Cover your chimney and stove pipe outlets with a non-flammable screen. Use metal screen material with openings no smaller than 3/8-inch and no larger than 1/2-inch to prevent embers from escaping and igniting a fire.
Keep closed seasonally: Close the fireplace flue during wildfire season when the chimney is not being used.
Vents
Mesh screening: Install 1/16-inch to 1/8-inch noncombustible, corrosion-resistant metal mesh over vents to block embers. Avoid fiberglass or plastic meshes, which can melt.
Advanced venting: It is recommended to replace vents with California State Fire Marshal-approved flame and ember-resistant vents (State Fire Marshal Listed Wildland Urban Interface (WUI) Products Handbook) for enhanced protection.
Be aware: These fire protection modifications may reduce airflow and ventilation to attics and underfloor spaces. Be sure to consult your local building official for ventilation requirements in your area before replacing or covering your vents and hire a licensed contractor to complete the project.
Windows
Dual-pane installation: Fit dual-paned windows with at least one tempered glass layer to withstand fire-induced breakage.
Size consideration: Limit the size and number of windows facing large vegetation areas to reduce radiant heat exposure.
Screen addition: Add screens to all operable windows to catch embers and reduce heat.
Walls
Material selection: Avoid flammable siding. Preferred materials include stucco, fiber cement, or specially treated wood.
Full coverage: Ensure the selected materials extend from the foundation to the roofline for comprehensive protection.
Decks
Fire-resistant materials: Construct decks from ignition-resistant building materials* like composite.
Under-deck clearing: Maintain an ember-resistant zone beneath decks by removing all flammable materials.
Slope consideration: For decks extending over slopes, establish a defensible space below to deter flame ascent.
Patio Covers
Matching materials: Use the same ignition-resistant materials on patio covers as those on your roof.
Eaves and Soffits
Construction: Box in eaves using ignition-resistant or noncombustible materials to prevent ember entry.
Garages
Emergency tools: Store a fire extinguisher and basic firefighting tools within easy reach.
Power backup: Equip garage doors with battery backups to ensure functionality during power outages.
Ember seals: Apply weather stripping around and under the garage door to block ember entry.
Fences
Material transition: Use noncombustible materials for the portion of the fence that connects to the house to prevent fire spread.
Addresses
Clear marking: Your home’s address should be easily visible from the street for quick identification by emergency responders.
Driveways and Access Roads
Clearance maintenance: Keep a minimum of 10 feet of vegetation clearance on either side of driveways and access roads.
Emergency access: Ensure gates open inward and are wide enough for emergency vehicles, and keep overhead branches trimmed.
Rain Gutters
Regular cleaning: Keep gutters free from plant debris to prevent ember ignition.
Drip edge installation: Add a noncombustible metal drip edge to protect the roof’s edge from ember exposure.
Gutter guards: Use noncombustible gutter covers to keep out debris and reduce maintenance.
Water Supply
Hose availability: Install long garden hoses at your property that can reach all areas, including roofs and decks.
Supplementary water sources: Consider installing pumps for pools or wells to increase water availability during fires.
Final Thoughts
Wildfires are unpredictable, but preparation puts the odds back in your favor. By hardening your home and maintaining defensible space, you’re not only protecting your property—you’re helping safeguard your family, your neighbors, and your entire community. If you have questions about whether your home meets compliance guidelines for local defensible space standards give us a call! Not sure where to get started? Start by calling us!
