Siding in a Fire Zone: Fiber Cement, Stucco, Treated Wood or Vinyl?

Which Los Angeles homes are in a fire zone?

The State Fire Marshal maps Fire Hazard Severity Zones, and the City and County of Los Angeles adopt them. The Very High zone takes in the hillsides south of Ventura Boulevard in Sherman Oaks, Studio City and Encino, the Hollywood Hills, Granada Hills north of Rinaldi, Sun Valley's foothill edge, all of Calabasas, all of Malibu and the canyons between them. The parcel map at the city or on the State Fire Marshal's viewer shows whether a house is inside; most hillside houses are.

What changed on January 1, 2026

The 2025 California Building Code repealed Chapter 7A, the old materials-and-construction chapter for wildfire areas, and moved its rules into a new stand-alone code, the 2025 California Wildland-Urban Interface Code (Title 24, Part 7). Two things matter for a re-side. First, the code applies to additions, alterations and repairs in a fire hazard zone, not only to new houses, so replacing siding triggers it. Second, it says in so many words that paints, coatings and stains are not an approved method of protection: no product you brush on makes a wood wall comply.

Siding materials in a fire zone at a glance

Why fiber cement is the usual answer

It does not burn, it looks like the wood lap or board-and-batten the hillside houses were built with, it takes paint for a decade and it needs no extra layer to comply. On a canyon house with cantilevered decks and three levels, as on the Calabasas project, it also solves the termites and the sun that had finished the original wood. Stucco is the other common answer on Spanish and Mediterranean houses in Calabasas and Malibu; metal suits modern houses.

The details the code also looks at

A re-side opens the wall, which is the moment to handle the other wildland-urban interface items: enclosed or noncombustible eaves and soffits, metal flashing at the base of the wall, vents with ember-resistant mesh, gaps at the bottom of siding closed so embers cannot lodge, and the first few feet above grade treated as the most exposed part of the wall. These are the same places water gets in, so the fire detailing and the water detailing are one job.

Permits in fire-zone cities

Calabasas and Malibu permit through their own building departments and apply the wildland-urban interface code with their own checklists; Calabasas asks for the fire-zone worksheet on exterior work. Inside the City of Los Angeles, a re-side is an express permit at LADBS over solid sheathing with an approved barrier, and the hillside parcels south of Ventura Boulevard and in the Hollywood Hills carry the fire-zone requirements on top. The permits-by-city guide covers who files where.

What a fire-zone re-side costs

The material does not cost more for being in a fire zone; the site does. Scaffolding on a slope, material carried by hand, and the extra detailing at eaves, vents and the wall base add to the planning ranges: fiber cement lap $13–$22 per sq ft of wall, three-coat stucco $11–$20, metal $12–$30, compiled from published Los Angeles pricing. A three-level hillside house can run six weeks where a flat single-story house takes 2–4. Insurance carriers increasingly ask about exterior materials in these zones, and a documented, permitted noncombustible exterior is worth having in writing.

Stucco or fiber cement in a fire zone?

Both comply, so the choice is the house. A Spanish or Mediterranean house in Calabasas or Malibu keeps its character with three-coat stucco, and a sound stucco wall can simply be re-coated, which no siding can match for cost. A wood-sided canyon house, a mid-century post-and-beam in the Hollywood Hills or a Craftsman in the foothills reads right in fiber cement lap or board-and-batten, and fiber cement takes paint for a decade where wood needed it every few years. On cost the two overlap once the wall is open, $11–$20 per sq ft of wall for three-coat stucco and $13–$22 for fiber cement lap; stucco takes longer because each coat cures, fiber cement goes up in days. Metal suits modern houses and is the lightest option on a slope where every pound is carried by hand.

Insurance, resale and the paper trail

Carriers in the fire zones increasingly ask what the exterior is made of, and some non-renewals in the hills have turned on wood siding and open eaves. A permitted re-side in a noncombustible material, with the inspection record and the product listings in the file, is an answer you can hand to an insurer or a buyer. We photograph the opened wall, the flashing and the eave and vent details before the siding closes them, and the permit card and manufacturer documentation stay with the house.

What we recommend

Confirm the zone on the parcel map, then choose between fiber cement and stucco by the architecture, with metal for modern houses and treated wood only where the look demands it and the listing exists. Have the eaves, vents and wall base detailed at the same time, because the wall is open once. Right Image Builders builds to the wildland-urban interface code with its own crew and has done so on several hillside, Calabasas and Malibu exteriors; see fiber cement siding and siding replacement.

Sources (checked October 2026): 2025 California Wildland-Urban Interface Code (Title 24, Part 7), effective January 1, 2026, which replaced Chapter 7A; applies to alterations and repairs in Fire Hazard Severity Zones; coatings are not an approved method of protection; CAL FIRE Office of the State Fire Marshal: Fire Hazard Severity Zone maps and the Wildland-Urban Interface building materials listing; University of California Agriculture and Natural Resources, Fire Network: siding and exterior wall materials in wildfire areas; LADBS Information Bulletin P/GI 2020-003, Express Permits: re-stucco (item 3), vinyl/wood/fiber cement siding over solid sheathing with an approved water-resistive barrier at 5 feet or more from property lines (item 20), replacing siding with stucco (item 21), dry-rot repair under 10 percent of replacement cost (item 16); Right Image Builders' 2026 siding planning ranges, compiled from published Los Angeles pricing (First Builders LA, Stucco Champions, MyCali Builders, Cost vs. Value 2025 Los Angeles; national guides as a check) and labeled as such; per square foot of wall area including tear-off, weather barrier, flashing and trim, paint separate; Right Image Builders service and neighborhood pages (2026 planning ranges, timelines, permit authorities). Cost figures are Right Image Builders' 2026 planning ranges from its service and neighborhood pages.