This article describes the purpose of California Building Code Chapter 7A. This code was created in the year 2008, in an effort to address the greatest fire danger to homes: tiny, wind-blown embers that can travel for miles.
Does Your Home Have Modern Ember Defense?
Research consistently shows that the majority of homes lost in wildfires are ignited by airborne embers.
Wildfire embers can travel up to 2 miles on the air, and if an airborne ember enters a home's exposed attic vents, it can cause home ignition in as little as 60 seconds.
Recognizing this ember threat, California enacted a landmark update to its building code that fundamentally changed how homes are built in California.
This update to the California Building Code, known as Chapter 7A, went into effect for new construction on January 1, 2008.
So, the critical question for any homeowner is: was your home built before or after 2008?
The answer can tell you a lot about your home's ember-related vulnerabilities, and whether you should consider adding supplemental ember-defense mechanisms.
We've created a tool that allows you to enter your address in order to see what year your home was built; click here to find out when your home was built.
If it turns out that your home was built before 2008, then please contact us about installing Ember-Resistant Vent Screens on your home.
Before 2008: A Dangerous Standard of Construction
Before 2008, homes in wildfire-prone zones were often built with materials that are (now) known to be highly susceptible to ember attacks.
If no renovations have been made to your home since 2008, then your home has increased-vulnerability to ignition from embers.
Common vulnerabilities in these older homes include:
- Combustible materials: Wood shake roofs, untreated wood siding, and single-pane windows were more common, all of which can fail quickly when exposed to the radiant heat and embers from a wildfire.
- Vents with large openings: Attic, foundation, and gable vents often had 1/4-inch mesh screens, which are large enough to allow dangerous embers to pass through and ignite materials inside your attic or crawlspace.
- Vents in vulnerable locations: It was common practice to place vents directly on the underside of roof eaves (soffits). During a fire, heat and embers get trapped under these eaves, providing a direct pathway into the attic.
If your home has these kinds of gable vents, eave vents, or foundation vents, then you might be a good candidate for installing ember-resistant vent screens.
After 2008: What Chapter 7A Changed
California Building Code Chapter 7A established a new set of minimum standards for the exterior of a building to increase its ability to resist the intrusion of flames and embers.
For any new home built after January 1, 2008, in a designated Fire Hazard Severity Zone, the following features became mandatory:
- Fire-Rated Roofs: Only Class A fire-rated roof coverings are permitted. Gutters must also have covers or other means to prevent the accumulation of flammable debris like dry leaves.
- Ignition-Resistant Walls: Exteriors must be made of noncombustible or ignition-resistant materials like stucco, fiber-cement, or heavy timber.
- Safer Windows and Doors: Windows must be dual-pane, with at least one pane made of tempered glass, which is far more resistant to breaking under high heat. Exterior doors must be solid-core or have a fire-resistance rating.
- Protected Decks and Eaves: Decks must be built with fire-resistant materials. The underside of roof eaves and overhangs must be enclosed ("soffited") and protected with noncombustible materials to deny embers a place to lodge and ignite.
The Biggest Change: Ember-Resistant Vents
Perhaps the most significant and impactful change in Chapter 7A was the complete overhaul of how homes are ventilated. Vents are necessary to prevent moisture buildup, but home vents are also a primary pathway for wildfire embers to enter your home's attic.
The new code mandated several critical changes:
- Finer, Stronger Mesh: All vents must now be covered with a noncombustible (metal) mesh with openings between 1/16-inch and 1/8-inch—small enough to block most dangerous embers. Plastic or fiberglass mesh, which can melt or burn, is prohibited for ember-resistant vent screens.
- No More Standard Soffit Vents: The code outright prohibited traditional vents on the underside of eaves in most cases. This was a massive shift in construction practice, forcing builders to find safer ways to provide attic ventilation.
- A New Generation of Vents: In response, manufacturers developed specialized ember-resistant vents. These vents use advanced designs like baffles, fine double-layer mesh, and intumescent coatings that swell up and seal the vent shut when exposed to high heat.
Using these state-approved vents is now a common way to comply with the code.
By hardening these small but critical entry points, the odds of a home surviving an ember storm increase dramatically.
If your home has older, unprotected vents, upgrading them is one of the most effective steps you can take. For more information on modern vent solutions, you can explore ember-resistant vent screens.
Does Your Home Need an Ember-Defense Upgrade?
The answer comes down to your home's age and location.
- If your home was built BEFORE 2008: It is almost certain that your home does not have the wildfire protections mandated by Chapter 7A. Your vents, eaves, and other exterior features are likely vulnerable. Retrofitting your home, especially by installing ember-resistant screens on all vents, is a critical step toward protecting your property. You can learn more about common home vent types here.
- If your home was built AFTER 2008: Your home was likely built to these higher standards. Post-fire analyses have shown that homes built to Chapter 7A code are significantly more likely to survive a wildfire. However, it is still wise to inspect your home's exterior, ensure vents are clear and intact, and maintain your defensible space.
If you are unsure about your home's vents or want to explore upgrading them to modern, ember-resistant standards, professional installation can provide peace of mind.
CBC Chapter 7A: Proven Strategy for Saving Homes
The implementation of California Building Code Chapter 7A has been a proven success.
By focusing on hardening homes against the primary threat of embers, these standards have demonstrably saved properties in major fire events.
While newer homes have these protections built-in, owners of pre-2008 homes can take proactive steps to significantly reduce their risk.
The most effective place to start is by securing the most vulnerable entry points: your vents.
To learn more about how you can protect your home, visit our page on Ember Resistant Vent Screens.
Disclaimer: This article is provided for informational purposes only, and is based on our online research of publicly available documents. Total Screen is not an expert on building codes. Homeowners should consult with their local fire department and building officials for authoritative guidance and to verify all requirements for their specific property. The regulations and best practices for wildfire safety are continually evolving.
Additional Information Sources:
- California Department of Housing and Community Development, 2010 California Building Code, Chapter 7A
- Fire Safe Marin, Fire-Resistant Vents
- Fire Safe San Mateo County, California Wildland Urban Interface Code Information