What is home hardening?

It is the process of upgrading or retrofitting some components of your home so they are resistant to ignition from ember storms, radiant heat, and direct flame.

Why should I harden my home?

In wildfires, 60-90% of home loss is due to embers. Embers can originate from an approaching wildfre or small parts of nearby burning vegetation and construction materials (e.g., an adjacent structure or ADU, storage shed, wood pile). Embers can ignite a home directly if they enter an attic through a vent. They can ignite a home indirectly by igniting a mulch bed or vegetation located close to a home. Reducing the vulnerability of homes to ember ignition will increase the chance of homes and neighborhoods surviving a wildfire.


Where do I start?

The foremost study on home hardening is NIST Technical Note 2205 which recommends 40 actions that should be taken. So, where should you focus your efforts? This image from Sustainable Defensible Space shows the relative cost of upgrading the listed features to ember-resistant materials and design compared to the priority level which indicates the features most vulnerable to wildfires and embers.

The four highest priority items are installing a fire resistive roof, addressing your deck, installing non-combustible gutter guards and replacing or retrofitting the vents to your attic, basement and crawlspace. The latter two are inexpensive and recognized as being very effective.

Learn much more about home hardening by using the two buttons below.

Source: https://defensiblespace.org/house/house-upgrade/


Find a Contractor to Help You

The City of Berkeley provides a listing of contractors that specialize in home hardening as a service to the public. The City of Berkeley makes no representation about the quality of work performed by these contractors and residents must perform their own research to ensure competency, appropriate licenses and insurance are in place and valid, and that there are acceptable references.


More Hardening Resources for a Deeper Dive

  • [Click Here] Includes a Low-cost Retrofit List , a Wildfire Home Retrofit Guide and a Wildfire Survey to get a custom checklist

  • [Click Here] Lots of good information and helpful videos that illustrate each component.

  • [Download Here] Structural losses in wildfires have been attributed to exposures from embers (firebrands) and fire (radiation and/or convection). As structural losses continue to increase, there is need for a comprehensive hazard assessment and mitigation methodology to harden appropriate structures and parcels effectively and efficiently against ember and fire exposures.

    The science-based methodology in this report uses the knowledge collected from post-fire field observations spanning over a dozen years and tens of thousands of hours of field data integration and analysis, and utilizes the latest technical knowledge gained from laboratory and large-scale research in fire propagation and hazard mitigation in the WUI.

    The study is the result of a sixteen-month collaborative effort between NIST, the California Department of Forestry and Fire Protection (CAL FIRE), and the Insurance Institute for Business and Home Safety (IBHS).

  • [Download Here] A series of field experiments were conducted to examine the effects on fire spread toward a structure for combustible fences and mulch under conditions that may be encountered in a wildland-urban interface (WUI) fire.

    The fire behavior of a variety of materials, designs, and configurations were studied under various wind conditions in 187 experiments.

    A small structure was located between 0 m and 1.83 m (0 ft to 6 ft) downwind of the fence or mulch bed as a target for flames and firebrands. A target mulch bed at the base of the structure tested the ability of firebrands produced by the burning fence and mulch bed to ignite spot fires that threatened the structure.

  • [Download Here] Wildfire Prepared Home™ was developed to help you protect your home from wildfire. The requirements described here are based on years of scientific research by the Insurance Institute for Business & Home Safety (IBHS). Our science has demonstrated that, when applied together, these specific actions reduce the wildfire risk to your home and property.

  • [Click Here] The key to preventing wildfires from becoming disasters is to keep them from entering and spreading into the built environment. IBHS has identified key vulnerabilities for suburban neighborhoods and communities; these insights build on findings published by the fire protection community and the best experimental and field research to date.

  • {Download Here] Wind-blown embers are the principal cause of building ignitions. Although the importance of embers (also called brands or firebrands) has been understood for a number of years, the ability to evaluate them in a laboratory setting has been a relatively recent development.

    The objective of this study was to clarify the relative importance of vents, including style, type and location of the entry of wind-blown embers. At the time this project was conducted, three vents had been accepted for use by the California OFSM. These vents were incorporated into the experimental design.

  • [Download Here] Fences and mulch contribute to the spread of wildland fires. They act as both ignition targets and as sources that may themselves ignite nearby objects through direct flame contact and firebrand generation. The linear nature of fences gives them the capability of spreading fire over long distances.

    This paper presents the findings from outdoor experiments that investigated the spread of fire through firebrand spotting from fences and mulch beds near a structure in a wind field. A variety of fence and mulch types and materials were tested. Fence type, proximity to the structure, wind speed, and type of ground cover beneath the fence all affect firebrand spotting.

  • [Download Here] Climate change, increased wildland fuels, and residential development patterns in fire-prone areas have combined to make wildfire-risk mitigation an important public policy issue. One approach to wildfire-risk mitigation is to encourage homeowners to use fire-resistant building materials and to create defensible spaces around their homes. We develop a theoretical model of interdependent household wildfire risk and examine its implications for a hypothetical fire-prone community. Results indicate that homeowners wildfire risk reduction actions can have significant, positive spillover effects on the wildfire risk of neighboring houses. In such cases, individual homeowners will engage in inefficient levels of wildfire-risk mitigation. We also demonstrate that wildfire risk reduction is most effective when concentrated in houses at the interface of communities and wildlands.

  • [Click Here] Sam Manzello (NIST) presenting on firebrand research targeted on quantifying structure vulnerabilities to wind-driven firebrand showers. This type of firebrand research was never possible prior to the development of the NIST Firebrand Generator, also referred to as the NIST Dragon.