Roof Fire Class, Hazard Zones and Solar

In March 2025, CAL FIRE's Office of the State Fire Marshal issued redrawn Fire Hazard Severity Zone maps for Southern California, including the City of Los Angeles. The Los Angeles County Fire Department expected the update to increase the number of parcels affected by hazard-zone requirements.

On 1 January 2026, the 2025 California Wildland-Urban Interface Code — Title 24, Part 7 — became mandatory, consolidating wildfire construction requirements that previously sat in Chapter 7A of the Building Code.

If you are replacing a roof, or putting solar on one, both of those changes can reach your project. This page explains what applies, in what order, and what it means for an array.

Three points about how this works matter more than the maps themselves:

• Zones are classed moderate, high or very high, based on terrain, fire history, weather patterns and fuel.
• Local agencies must adopt the recommended maps by ordinance within 120 days.
• A local agency may not lower a zone the state has recommended. It may raise it, or add areas the state did not designate.

The Los Angeles County Fire Department expected the number of affected parcels to increase under the updated maps. Where that happens, a household can meet hazard-zone construction requirements for the first time on a house that has stood unchanged for decades — which is why the designation is worth checking for your own parcel rather than assumed from what applied before.

Check the current designation for your own parcel rather than relying on memory or on a neighbor's experience. A designation from before 2025 may no longer be current, and a zone can be raised locally after the state's recommendation.

For buildings that already exist, the trigger is replacement:

• A roof covering that is replaced, or 50 percent or more replaced within a 12-month period, must be replaced with a covering meeting the new-construction requirement.
• All roof covering applied during an addition, alteration or repair must meet at least a Class A classification.

The California Residential Code points there too. CRC 2025 R902.1.1 states that roofing requirements for structures within Fire Hazard Severity Zones or a WUI area shall also comply with Part 7 — the two codes stack rather than substitute.

CRC 2025 R902.1.2 applies to everywhere else:

The entire roof covering of every existing structure where more than 50 percent of the total roof area is replaced within any one-year period, the entire roof covering of every new structure, and any roof covering applied in the alteration, repair or replacement of the roof of every existing structure, shall be a fire-retardant roof covering that is at least Class C fire classification.

And R902.1 adds a proximity rule independent of any map: a minimum Class A, B or C roofing is required where the edge of the roof deck is less than 3 feet from a lot line. On narrow urban lots — much of the older city — that catches a great many houses.

So the structure is: Class A inside a hazard zone; at least Class C on a substantial re-roof anywhere; and a rating required regardless where the roof edge is within three feet of the property line.

• brick, masonry, and exposed concrete roof deck;
• clay or concrete roof tile, slate, or ferrous, copper or metal sheets and shingles installed on non-combustible roof decks — or metal sheets on non-combustible framing without a deck;
• copper sheets of at least 16 ounces per square foot over combustible decks;
• slate installed over underlayment over ASTM D226 Type II underlayment over combustible decks.

The practical reading, especially in the hillside neighborhoods where hazard zones concentrate: a tile roof is frequently already carrying the fire classification the zone requires. That does not make the rest of the WUI package go away — vents, eaves, decks and cladding have their own requirements — but the roof covering itself may not be the obstacle.

CRC 2025 R902.4 requires that rooftop-mounted photovoltaic panel systems installed on or above the roof covering be tested, listed and identified with a fire classification in accordance with UL 2703, installed per the manufacturer's instructions and their listing. Class A, B or C systems must be installed where a jurisdiction requires them by law, or where the roof edge is less than 3 feet from a lot line. R907.4 repeats the UL 2703 listing requirement, and R907.5 adds that systems on or integral to a roof must comply with the California Fire Code.

Here is the point worth carrying away, because it changes what you ask an installer:

UL 2703 rates the system, not the panel. The classification belongs to the combination of module, mounting system and roof deck. A rack tested with a given module type and rated Class A carries that rating with other modules of the same type — but a panel's own spec sheet cannot tell you the fire class of the installed assembly.

So the question is not "are these panels Class A?" It is "which UL 2703 system listing is this array being built to, and does it hold Class A on my roof deck?" That has a documentary answer, and an installer who cannot produce it is not in a position to certify the assembly.

For building-integrated products — where the photovoltaic is the covering — the standard is different: R902.3 requires BIPV systems installed as the roof covering to be tested, listed and labeled to UL 7103.

• Two pathways minimum, on separate roof planes, from lowest roof edge to ridge, at least 36 inches wide, with at least one on the street or driveway side. Pathways must be over areas capable of supporting firefighters and clear of vents, conduit and mechanical equipment.
• Ridge setback: at least 18 inches clear on both sides of a horizontal ridge where the array occupies no more than 33 percent of the plan-view roof area; 36 inches above 33 percent.
• With an automatic sprinkler system installed to NFPA 13D or Section R309, the thresholds relax: 18 inches up to 66 percent coverage, 36 inches above it.

And one requirement that constrains real layouts and is almost never discussed in consumer material — R329.6.3:

Panels and modules installed on dwellings or townhouses shall not be placed on the portion of a roof that is below an emergency escape and rescue opening. A pathway not less than 36 inches wide shall be provided to the emergency escape and rescue opening.

That is the bedroom egress window. The roof slope beneath it must stay clear, and a 36-inch path must reach it. On a small roof with a bedroom window facing the best solar exposure, this is a real design constraint, and it is better raised at layout than at inspection.

R329.6 carries four exceptions: detached non-habitable structures such as garages, carports and solar trellises; where the enforcing agency determines rooftop operations will not be employed; roofs sloped 2:12 or less; and BIPV systems listed to UL 3741 where firefighting operations have been determined not to expose firefighters to shock hazards.

We are deliberately not publishing a count of how many of our installations fall inside a Fire Hazard Severity Zone. We hold coordinates for the projects, but we have not run the geospatial intersection against the 2025 maps, and a number produced any other way would be a guess. When that analysis is done properly, the figure will appear here.

What we can say from the records: these are the neighborhoods where the roof covering conversation and the array layout conversation have to happen together, because the zone requirements, the Class A assembly and the pathway geometry all land on the same roof at the same time.

1. If you are in a zone, the roof assembly must be Class A — and a tile, slate or metal-on-non-combustible-deck roof may already satisfy it by construction.
2. If you are not in a zone, a re-roof of more than half the roof area within a year still requires at least Class C, and a roof edge within 3 feet of a lot line requires a rating regardless.
3. For the array, ask which UL 2703 system listing it is built to, and whether it holds Class A on your deck.
4. Before the layout is fixed, identify every emergency escape and rescue opening. The roof below it stays clear.

• California Residential Code 2025, R902.1 (minimum class; lot-line rule; Class A assembly exceptions), R902.1.1 (WUI cross-reference), R902.1.2 (Class C on >50 % replacement), R902.3 (BIPV, UL 7103), R902.4 (rooftop PV, UL 2703).
• California Residential Code 2025, R907.4, R907.5 — UL 2703 listing; California Fire Code compliance.
• California Residential Code 2025, R329.6, R329.6.1, R329.6.2, R329.6.2.1, R329.6.3 — pathways, ridge setbacks, sprinklered alternative, emergency escape opening rule, and exceptions.

Figures on this page come from the primary sources below and, where noted, from Cali Energy calculations using the stated assumptions. Rates, incentives, and program terms change; each was verified September 1, 2026.

1. 2025 California Wildland-Urban Interface Code (Title 24, Part 7), Chapter 5 — Class A requirement in Fire Hazard Severity Zones (ASTM E108 / UL…
2. LADBS — Fire Hazard Severity Zone Supplemental Checklist referencing the 2025 CWUIC
3. LAFD — 2025 CAL FIRE Fire Hazard Severity Zones map recommendation
4. CAL FIRE 2025 LRA maps for Los Angeles County, issued 24 March 2025; 120-day adoption requirement; local agencies may not lower a recommended zone
5. UL Solutions — PV mounting systems certification; fire classification applies to the system
6. LA County Public Works, Handout H004 — Fire Classification for Roof-Mounted PV Systems