Cal Fire and the El Dorado Hills Fire Department recognize the Insurance Institute for Business and Home Safety's (IBHS) wildfire research and mitigation measures as best practices for homeowners who want to protect their homes from embers and flames.

IBHS home mitigation measures include California Building Code Chapter 7A, considered the most stringent building code for wildfire-prone areas in the country.

Currently, the Fire Department requires new construction on Serrano custom lots with less than a 30-foot setback from the property line to comply with IBHS Wildfire Prepared Home Plus certification requirements. These requirements include a noncombustible five-foot buffer around houses, called Zone 0, and attached metal fences and gates.

The Insurance Institute for Business and Home Safety (IBHS) is a nonprofit organization that researches how wildfires impact homes, identifies vulnerabilities, and develops mitigation actions that homeowners can implement to reduce wildfire risks. They field test their mitigation actions to ensure they address vulnerabilities.

IBHS

IBHS has a research center in South Carolina. It's a big facility with 105 6-foot-diameter fans and a tall concrete structure room to construct full-size structures. The facility can blow up to 135-mile-an-hour winds and burn embers across a structure to test mitigation measures.

IBHS Best Practices

Mitigations Against Embers and Flames*

Roofs

Roofs are prone to ember accumulation and eventual ignition if they are not fire-resistant. A Class A roof covering reduces this vulnerability.

Ensure roof lines are clear of debris so that fires won't ignite on the roof line or up against a dormer.

Serrano roofs are Class A rated.

Gutters

Leaves accumulate in gutters, providing embers with a fuel bed. Vinyl gutters will melt and drop to the ground

Gutters and downspouts should be metal.

Noncombustible gutters also shield the facia board from flame exposure.

Clear debris from the gutter and install a metal gutter cover.

Vents

Old-style vents can allow embers and direct flame to pass through them. Vent openings must be protected with a 1/8-inch or finer non-combustible mesh screen to prevent large embers from entering the house.

Dryer vents should be louvered, so they close when the dryer stops.

Zone 0

IBHS's research and validation testing concluded that removing all vegetation and combustible items within 5 feet of the home is the most effective way to minimize pathways to home ignition and reduce the risk of wildfire.

Attached Wood Fences and Gates

Flames from a burning fence can threaten eaves and nearby windows.

Replace wood fences and gates with metal inside Zone 0 to break the path of fire to a home.

Smoldering bark ignited a wood fence fire that traveled to the Serrano home in the photo. Flames broke windows and entered the house.

Decks

Deck assemblies (walking surfaces, joists, and posts) are vulnerable to embers and flames. Embers can fall between deck boards and ignite the joists beneath or combustible items under the deck area, allowing fire to reach the house.

Keep the underdeck area well-maintained with no combustible materials. Where decks are low to the ground, enclosing the underdeck area with 1/8-inch or finer noncombustible mesh reduces the likelihood of debris and ember accumulation.

When building a deck, choose a noncombustible deck assembly with a solid walking surface.

Create 5-foot noncombustible zone around the deck.

Accessory Buildings

When spot fires ignite accessory buildings like sheds and gazebos, short local flames become tall flames that radiate significant amounts of heat and touch nearby buildings.

Accessory buildings should be moved further than 30 feet from the house to limit these exposures. If unable, they should be built with the same mitigation measures as the home.

Eaves

Eaves can trap heat and fire. Fire can get through vents and travel down the roof line.

Protecting eaves with ember-resistant vents and noncombustible soffits mitigates the ignition potential.

Siding

The spread of fire can be slow through walls, but surface flame spread on combustible siding occurs quickly.

Serrano homes have noncombustible exterior siding.

Windows

Windows are vulnerable to flame contact and heat radiation. Multipaned windows are more resilient by providing multiple layers of protection before flames penetrate the home.

Serrano homes have dual-paned windows.

Research is underway to examine windows as an assembly rather than the glass component. IBHS testing revealed that direct flames on plastic and vinyl window frames deformed them, causing the whole window to fall out.

Doors

Flames are less likely to reach exterior doors with proper Zone 0 space around the home. However, wind-blown embers may still accumulate at the base of a door or penetrate small openings around the door and ignite the door jam. Therefore, the entire door assembly should be mitigated. Fire-rated doors are the most practical solution due to the lack of noncombustible door assemblies on the market.

Bay Windows

Bay windows trap heat underneath them. Enclosing this area with noncombustible material eliminates the risk.

* Hedayati, F., Quarles, S., and Hawks, S. (April 2023). Wildland Fire Embers and Flames: Home Mitigations That Matter, Insurance Institute for Business and Home Safety.

County Ordinance

Hazardous Vegetation shall mean any combustible vegetation that endangers public safety by creating a Fire Hazard. Hazardous Vegetation includes material that, in its natural state, will readily ignite, burn, and transmit fire from native or landscape plants to any Structure or other vegetation. Hazardous Vegetation includes, but is not limited to, dry grass and leaves, brush, weeds, green waste, dead or dying trees, low-hanging branches, litter, or other flammable vegetation that create a Fire Hazard.

Parcel owners are responsible for creating and maintaining the required 100-foot defensible space around combustible Structures on their property but not beyond the property line.

Suppose a Structure's required 100 feet of defensible space crosses the property line. In that case, the adjacent property owner shall remove hazardous vegetation that poses a fire hazard within 100 feet of that Structure.

A greater clearance distance, up to 300 feet, may be required if the clearing is necessary to significantly reduce the risk of transmission of flame or heat sufficient to ignite the Structure and no other feasible mitigation measure is possible to reduce the risk of ignition or spread of wildfire to the Structure.

The El Dorado County Hazardous Vegetation and Defensible Space Ordinance 5186 requires 100 feet of defensible space from all sides of combustible structures in unincorporated areas, which includes El Dorado Hills.

Before the close of any Real Estate Transaction in a High Fire Hazard Severity Zone (Custom homes, Fairway Villas, and Villages K6, J3B, and J. Lot H), the seller shall obtain a defensible space inspection report from the Fire Department documenting that the property complies with the Ordinance and provide that report to the buyer at or before the close of escrow.

County Emphasis Areas

The El Dorado Hills Fire Department enforces the Ordinance with home inspections and education.

Each year, El Dorado County identifies County Emphasis Areas and conducts defensible space inspections in partnership with the El Dorado Hills Fire Department.

These inspections provide homeowners with valuable information on meeting their defensible space requirement and making their homes more resilient to wildfire.

Residents in the County Emphasis Areas will receive a Notice of Defensible Space Inspection, inspection timeframes, and an invitation to a local informational workshop.

Serrano is not in a County Emphasis Area this year.

Defensible Space Assessment

Fire Department defensible space inspectors Alex Borriague and Alec Dietrich assessed four Serrano Fire Safe Council board member properties: two custom homes and two production homes. They spent about 45 minutes at each property.

The council members found the assessment to be an essential educational experience. They appreciated the inspectors' flexibility in discussing front and back yard landscaping. We discovered that even small changes can significantly reduce risk, empowering us with knowledge to protect our properties.

If you want the Fire Department to assess your yard, submit an assessment request here.