Guide
A house in a mapped fire zone is one system, and a fire tests the weakest part of it. The roof edge, the vents, the glazing, the siding, the deck and the first five feet of ground decide more than the studs do. This page walks the decisions in the order a fire meets them, says what each material buys, and promises no rating, because a rating belongs to a tested assembly and not to a sentence.
I am Sebastian Moreno Rivera, the owner of Build And Decor Construction. In the City of Los Angeles the Very High Fire Hazard Severity Zone is a fire district, and structures there follow the Wildland-Urban Interface Code; the Resilient Yards pages name that line, and this page builds on it.
Embers land on the ground before they land on the house. The first five feet around the structure, Zone 0, are kept free of what burns: no combustible mulch, firewood or dead vegetation, and no new combustible fencing, as the Resilient Yards pages state the rule. Stone, gravel and mineral ground do the job, and the Zone 0 Courtyard is built on exactly that.
The roof is the largest surface a fire can reach, and its edge is where embers collect. A roof covering chosen for the zone by its listing, gutters that do not hold burning debris or are kept clear, and an eave detail that closes the gap between the roof and the wall are one decision, not three. The covering alone does little if the edge is open.
Attic and crawl-space vents are the holes a house breathes through, and embers follow the air. Vents built to keep embers out, placed and sized to keep the house breathing, are a small line item and one of the most consequential. They are specified with the roof edge, not after it.
Windows fail by heat before flame reaches them, and a failed window is an open door. Multi-pane units with tempered glass, and frames that hold them through heat, are the decision. Large glass facing the hillside is where the view and the risk meet, and the brief says so in writing.
Siding and sheathing face the fire first; the stud behind them matters only once the skin is gone. Non-combustible siding, stucco or fiber-cement, over a sheathing and insulation detail specified for the zone, is the wall decision. Cold-formed steel studs do not burn, which is a real advantage inside the wall, and steel framing vs wood framing lays out the rest of that trade. The assembly is what the code tests; the stud is one part of it.
A wood deck against the house is a fire's ladder. Non-combustible decking, a closed or screened underside, and the ground beneath kept to the first-five-feet rule are the deck decision, specified with the wall it meets. On a hillside house the deck is often the single largest decision after the roof.
None of these works alone, and the materials question is one question: what is the house made of, from the ground five feet out to the ridge. The consultation writes that answer for your house, with each decision's trade-off and who builds it. The home resilience page sets fire beside water, earthquake and outage, and a house that has already burned has the fire damage rebuild page.