What Actually Burns Homes in a Wildfire
Flying embers destroy most homes lost in wildfires. They land on roofs, in gutters, against siding and in vents. One ember is enough.
Radiant heat can shatter windows and ignite wood siding from a burning house across the street.
Direct flame contact comes last. By then the outcome is usually decided.
In the January 2025 Palisades Fire, an estimated 85% of destroyed structures were lost in the first 60 to 90 minutes, before crews could reach most homes.
Passive Home Hardening
Passive hardening means building or retrofitting with materials that resist ignition. Nothing to monitor, nothing to switch on.
Roof
Your roof is the largest surface in an ember attack. Wood shakes, missing tiles and ridge gaps give embers a place to settle and smolder. A Class A roof is the most effective passive upgrade. See the CAL FIRE home hardening guide.
Gutters and Eaves
Gutters full of dry leaves and needles are ready-made ember fuel. Open eaves trap embers against the house. We specify stainless steel micro-mesh gutter guards and enclose open eaves with fiber cement soffit panels. See our Home Hardening Products Guide for the specific products we use.
Vents
Attic, soffit and foundation vents are open doors into the house. Ember-resistant vents are required for new construction in high-risk zones and are one of the cheapest, highest-impact retrofits. We install Vulcan Vents, ASTM E2886 certified and State Fire Marshal listed. See rated vent products in our Home Hardening Products Guide.
Windows and Doors
Single-pane windows can fail from radiant heat before flames arrive. Dual-pane tempered glass holds up far better. Doors should be solid-core with thresholds that keep embers out.
Siding and Walls
Vinyl melts and wood burns. Three-coat stucco, fiber cement and metal siding hold up best. Browse Fire Marshal-listed siding products to compare ratings and costs.
Fencing
A wood fence attached to the house is a fuse that leads fire straight to the wall. It is one of the most overlooked risks. Noncombustible fencing breaks that connection.
Defensible Space
Defensible space is the managed area around your home that slows fire and starves it of fuel. California law requires it in State Responsibility Areas.
Zone Zero (0 to 5 feet)
The five feet around your home matter most, because that is where embers pile up and fire jumps to the house. The statewide Zone Zero rule (no mulch, wood chips, dead plants or firewood in this band) is still in draft with the Board of Forestry. Berkeley and the Moraga-Orinda Fire District already enforce a five-foot noncombustible zone.
Zone 1 (5 to 30 feet)
Break up the fuel. Space trees so canopies do not touch, limb up low branches and leave gaps between shrub groups.
Zone 2 (30 to 100 feet)
Reduce overall fuel: keep grass low, clear dead growth and thin dense trees.
CAL FIRE publishes the official defensible space guidelines, including rules by slope.
Active Wildfire Defense
Hardening and defensible space lower the odds. They do not remove them. In high winds with a sustained ember shower, a hardened home can still ignite. The third layer is an automated exterior fire sprinkler system that wets the roof, eaves and perimeter before the fire arrives. Every automated system runs on its own, even after you have evacuated.
In the 2007 Ham Lake Fire in Minnesota, a University of Minnesota study found 46 of 47 structures with working exterior sprinklers survived, while only 18 of 48 without sprinklers did. See the full evidence from real fires.
Each system is designed for the property.
Service Tiers
Keystone
Roof sprinklers, smart controller and satellite monitoring automation.
Guardian, Most Popular
Adds eave sprinklers and dual detection with on-property cameras.
Fortress
Adds optional Class A foam, a biodegradable formula that rinses off after an event.
Add-ons for any tier: pool connection, water tank, booster pump and perimeter sprinklers. See full service details for more.
Wildfire Detection: Why It Decides Everything
The biggest design decision is when the system turns on. Start too early, at a fire miles away, and you can drain the water supply before the real threat arrives. That is why FireRoofs uses dual wildfire detection.
Layer 1: regional satellite wildfire monitoring and fire incident data within a 5-mile radius, along with local weather conditions, drive alerts and activation. Layer 2: cameras watch the area around the property for fire, send alerts and can activate the system.
Three threat levels: Early Warning, Active Defense and Maximum Defense. Water starts automatically for a confirmed fire and ramps up as the fire gets closer or conditions worsen. The owner can also start any threat level or individual zones manually from the app, or cancel. The controller has a physical emergency start button, and you get a push notification at every threat level change. See our technical specifications.
The Three-Level Threat Response
The system steps up through three levels, each with a stronger response. You can cancel at any stage, or start the system yourself from the FireRoofs app.
Water Supply Planning
A sprinkler system is only as good as its water. FireRoofs designs systems to run at 60 to 80 PSI, with a booster pump installed if the home’s pressure falls short.
In the Palisades Fire, municipal water failed under demand. That is why your own water supply matters. Your system can run straight from a pool or storage tank, or from city water with your pool or tank as a backup that switches over automatically if pressure drops. Either way, the house is not left depending on city pressure during a fire. An 18,000-gallon pool holds about 17 hours of the system’s heaviest watering. The system only uses water when a confirmed fire threatens your home, so a pool usually outlasts the event. Tanks are sized to run full defense for the hours chosen, about 5,000 gallons for 4 hours on a 3,000 sq ft roof.
Runs on your home’s generator or whole-home battery. Satellite internet is recommended.
Ready to See What Your Property Needs?
Every property out here is different. We’ll walk yours and tell you what it needs.
Request a Private ConsultationInsurance and the WUI Crisis
Major carriers have pulled out of high-risk zip codes, pushing homeowners in Saratoga, Woodside, Los Gatos and beyond onto the FAIR Plan. It caps dwelling coverage at $3 million, well below what many hillside homes cost to rebuild.
Carriers look for documented mitigation. SB 429 also creates a public wildfire risk model, so you can see more of how properties are scored. More on our insurance and WUI page.
California Regulations: Zone Zero and SB 429
The statewide Zone 0 rule (no combustibles within five feet of the home in State Responsibility Areas and High and Very High zones) is still in draft with the Board of Forestry (final draft considered August 19, 2026), with a phased rollout planned. Local rules vary. Saratoga’s tree ordinance, effective March 6, 2026, allows removal of trees within five feet of a home for wildfire safety. Woodside offers a $3,000 Defensible Space and Home Hardening Matching Fund and a free chipper program from May through November.
SB 429, effective January 1, 2026, requires a public wildfire catastrophe model. The California Fire Safe Council lists grants and local council contacts. Visit cafiresafecouncil.org.
Bay Area Risk by Community
Risk varies street by street. CAL FIRE’s Fire Hazard Severity Zone maps are the official source, but slope, wind and vegetation set the real exposure.
Very High Fire Hazard Severity Zones we serve include Saratoga, Los Gatos, Monte Sereno, Woodside, Emerald Hills, Portola Valley, Los Altos Hills, the East Bay Hills and the Santa Cruz Mountains.
High Fire Hazard Severity Zones we serve include Scotts Valley, Aptos, Danville, Pleasanton, Livermore, Morgan Hill, the San Jose and Fremont hills, San Ramon, Alamo, Dublin, Hayward, Castro Valley, Atherton and Menlo Park.
Check your city’s designation and fire history on our wildfire risk hub.
Where to Start
The strongest plan uses all three layers. Ready for a plan? We walk your property, test water pressure, inspect the roof and eaves, and send a full proposal within one to three business days.
Request a private consultation on our evaluation page or call (831) 705-0888.
Frequently asked questions
What is a wildfire defense system?
A wildfire defense system combines three layers of protection: passive home hardening, defensible space, and an automated exterior sprinkler system that pre-wets the roof, eaves, and landscape as a fire approaches. FireRoofs designs and coordinates these systems.
Do exterior sprinklers actually protect a home from wildfire?
Exterior sprinklers raise moisture on and around the structure so wind-blown embers are far less likely to ignite it. They are one layer of defense, most effective when combined with a hardened structure and maintained defensible space, and they depend on an adequate water supply and power.
How much does home wildfire protection cost?
Cost depends on roof size, water source, site access, and how many layers you add. Passive hardening and defensible space can be phased in over time, while an automated exterior system is a larger investment. See our cost guide and estimator for typical ranges for Bay Area properties.
What does California law require for home wildfire protection?
California requires defensible space under Public Resources Code 4291 and ember-resistant construction under Building Code Chapter 7A for homes in designated Fire Hazard Severity Zones. A statewide Zone 0 rule requiring a 5 foot noncombustible zone is still in draft with the California Board of Forestry, with a final draft considered in August 2026. Source: bof.fire.ca.gov.
Where should Bay Area homeowners start?
Start by confirming your Fire Hazard Severity Zone and your local defensible space rules, then harden the most exposed parts of the structure first: the roof, vents, and the first 5 feet. A private consultation can identify the highest-impact steps for your specific property.
External Resources
Reviewed by the FireRoofs Team. Last updated August 2026. All work is performed by licensed and insured contractors.