Why do some homes survive in a wildfire and others don’t? Fire hardened homes may be one reason. According to the California Fire Safe Council, “Fire hardened means your home is prepared for wildfire and an ember storm. It does not mean fireproof. Home hardening addresses the most vulnerable components of your house with building materials and techniques that increase resistance to heat, flames, and embers that accompany most wildfires.”
According to the University of California, wildfires spread by a combination of a moving flame front and the wind distribution of burning embers. Embers are small pieces of plants, trees, or buildings that are light enough to be blown through the air and can result in the rapid spread of wildfire when embers are blown ahead of the main fire, starting new fires. Embers cause the majority of wildfire home ignitions by igniting the home or vegetation or materials on or near the home that result in flames touching the house or radiant heat that may break a glass in a window.
CAL FIRE and other fire prevention experts provide some things you can do to harden your home and make it more fire resistant.
The roof is the most vulnerable part of the house. Homes with wood or shingle roofs are at high risk of being destroyed during a wildfire. Replace wood or shingle roofs with non-flammable materials like asphalt, clay, metal, or slate. Replace missing shingles. Plug gaps between your roof covering and sheathing to prevent ember entry. Install a metal angle flashing at the roof edge. Cover tile caps to prevent bird nesting.
Vents create openings for flying embers. Vent openings should be covered with 1/8 to 1/4-inch metal mesh. Do not use fiberglass or plastic mesh because they can melt and burn. Protect vents in eaves or cornices with baffles to block embers, as mesh is not enough.
Eaves and Soffits (Underside of Roof)
Protect eaves and soffits with ignition resistant or non-combustible materials. Whenever possible enclose open eaves. Caulk and plug gaps around exposed rafters and blocking. (Ignition resistant materials are those that resist ignition or sustained burning when exposed to embers and small flames from wildfires. Examples of ignition resistant materials include non-combustibles that don’t burn, exterior grade fire retardant treated lumber, fire retardant treated wood shakes and shingles listed by the State Fire Marshall (SFM), and any material that has been tested in accordance with SFM Standard 12-7A-5.)
Heat from a wildfire can cause windows to break even before the home ignites. This allows burning embers to enter and start fires inside the house. Single-paned and large windows are especially vulnerable. Install dual-paned windows with one pane of tempered glass to reduce the chance of breaking in a fire. Consider limiting the size and number of windows that face large areas of vegetation.
Wall products, such as boards, panels, or shingles, are combustible and not good choices for fire prone areas. Build or remodel walls with ignition resistant materials, such as stucco, fire retardant treated wood, or other approved materials. Remember to extend ignition resistant materials all the way from the roof to the foundation.
Decks are another large surface area on which embers can land. In addition to using ignition resistant decking, prevent debris from building up on or underneath your deck.
Screen or enclose rain gutters to prevent accumulation of plant debris.
Use the same ignition resistant materials for patio coverings as for a roof.
Cover chimney and stovepipe outlets with 3/8 to 1/2-inch metal mesh to prevent embers from entering and igniting a fire.
Have a fire extinguisher and a shovel, rake, and hoe available for fire emergencies. Use weather stripping around and under garage doors to prevent embers from blowing in. Store all combustible and flammable liquids away from ignition sources. Know how to operate your garage door when there is no power.
Use ignition resistant or non-combustible fencing materials. Separate wood fencing from your house with a metal or stone barrier.
Driveways and Access Roads
Driveways should be built and maintained consistent with state and local codes to allow fire and emergency vehicles to reach your home. Consider maintaining access roads with a minimum of 10 feet of clearance on either side, allowing for two-way traffic. Ensure that all gates open inward and are wide enough to accommodate emergency vehicles. Trim trees and shrubs overhanging the road to allow emergency vehicles to pass. Make sure your address is clearly visible from the road.
Have multiple garden hoses that can reach every area of your property. If you have a pool, consider getting a pump.
Don’t allow plant debris to build up in rain gutters attached to your house. You can prevent accumulation of leaves or pine needles by screening or enclosing gutters and making sure they are cleaned regularly. Install a non-combustible gutter guard to reduce accumulated debris.
Be sure the doggy door seals properly and remains closed during fire season.
Propane tanks and woodpiles should be moved away from the home. Replace organic mulch and flammable plants with non-flammable alternatives. Be sure items within five feet of your home are fire resistant.