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Building Code Reference

Got a CBC 1505.1 correction?

Roof fire classification

For builders in California, Greater Seattle, the Las Vegas area, the Denver area and Kansas City · CrossBeam Permits

What this code requires, how to fix it, and how cities and counties review it

What this code requires

CBC 1505.1 is the California Building Code section that sets the minimum fire-resistance classification for roof coverings on new and altered buildings. It requires roof coverings to meet at least Class A, B, or C fire ratings depending on the construction type and location of the building, with Class A required in Fire Hazard Severity Zones and Wildland-Urban Interface (WUI) areas under the California Wildland-Urban Interface Code. Reroofing projects, new construction, and additions all fall under this requirement. Plan-checkers flag it when the submitted roof material lacks a listed fire classification or when the specified class is too low for the zone.

How to fix it

  1. Confirm your FHSZ and WUI designation

    Before touching the drawings, look up the parcel on CAL FIRE's FHSZ viewer (fire.ca.gov/programs/fire-resource-assessment-program/fire-hazard-severity-zones). If the property falls in a State Responsibility Area (SRA) or locally designated fire hazard zone, the minimum required class is likely Class A. If it is a designated WUI area, the California Wildland-Urban Interface Code (Title 24, Part 7), which replaced CBC Chapter 7A and CRC R337 in the 2025 cycle, requires a Class A roof assembly. Print or screenshot the map result and keep it with your permit docs. This determines every decision downstream.

  2. Identify the correct minimum fire class for your project

    CBC 1505.1 ties the minimum class to construction type and location. Most single-family residential work in non-fire-hazard areas needs at least Class C. Any structure in a WUI area or fire-hazard severity zone needs Class A. Check the local jurisdiction's adopted amendments as well. Some cities have upgraded the default minimum to Class A across the board regardless of FHSZ status. If you are unsure what your jurisdiction requires, call the plan-check counter before resubmitting. Getting the wrong class on the second attempt means another full review cycle.

  3. Select a product with a current UL 790 or ASTM E108 listing

    The fire class must come from a listed assembly. The two recognized test standards for roof coverings are UL 790 (Standard for Tests for Fire Resistance of Roof Covering Materials) and ASTM E108. The product's spec sheet, ICC-ES evaluation report, or UL product listing page should state the class explicitly. Use the product name, manufacturer, and UL or ICC-ES report number as your citation on the drawings. Do not assume a shingle labeled as Class A by the manufacturer is the same as a UL-listed Class A assembly. The listing number is what the plan-checker is looking for.

  4. Add the fire classification call-out to the roof plan

    On your roof plan or exterior elevation sheet, add a note that reads something like: "Roof covering: [Product Name], Class A fire-rated per UL 790 / ICC-ES Report #[number], manufactured by [Manufacturer]." If the project uses different roof materials in different zones (sloped shingle plus flat modified bitumen, for example), add a separate call-out for each material. Every roof section must have a fire class noted. A single blanket note at the bottom of the sheet often fails because the reviewer cannot confirm it applies to each material type shown.

  5. Include the product listing documentation

    Attach the ICC-ES evaluation report or UL product page as a submittal exhibit. A one-page product spec sheet is usually enough if it clearly states the fire class and listing number. If you are using a fire-rated assembly that requires an underlayment to achieve its class (many Class A asphalt shingle systems do), the underlayment must also be noted and listed. A shingle alone without the required underlayment is not a complete Class A assembly under most listings. Flag this in your response to corrections letter to show the reviewer you have addressed the assembly question.

  6. Verify the roof deck and underlayment match the listed assembly

    Many fire-class listings are assembly-specific. A given shingle may achieve Class A only over a 7/16-inch OSB deck with a specific underlayment layer. If the deck is older tongue-and-groove boards or the underlayment is omitted, the assembly may only qualify for Class B or C even if the shingle itself carries a Class A label. On a reroof where the existing deck stays, confirm the deck type matches the product listing requirements. Note the deck material on your drawings or in your response letter.

  7. Resubmit with a response letter that addresses each correction item

    Plan-checkers work through your response letter first. Write one short paragraph for the 1505.1 item: state what fire class is required for this project based on its FHSZ status, name the product selected, cite the listing report number, and point to the sheet where the call-out was added. Keep it direct. Reviewers process dozens of corrections a day. A clear, specific response reduces the chance of a back-and-forth on a technicality.

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Why you got flagged

Here is why plan-checkers flag CBC 1505.1. The most common trigger is a roof spec that does not state the fire class at all. The drawings note a shingle product by name but skip the UL listing number and fire classification. The reviewer cannot confirm the material qualifies without that information, so the correction lands on you.

A second scenario: the project is in a mapped Fire Hazard Severity Zone (FHSZ) or WUI area, and the drawings specify a Class B roof covering. Class B is not sufficient in these zones, which require a Class A roof assembly. California expanded its WUI designations in recent years, so a property that sat outside the boundary when the lot was purchased may now be inside it. If the building department has the current CAL FIRE FHSZ map and your drawings do not reflect the upgraded requirement, you will get flagged.

Reroofing projects catch this too. A homeowner replacing worn asphalt shingles like-for-like may not realize the new material must still carry a current fire-class listing. If the replacement product is a lower-cost option without a valid UL 790 or ASTM E108 classification, the correction comes back citing 1505.1.

Finally, plan-checkers flag mixed-material roofs where one section (say, a flat TPO section joined to a sloped shingle section) is clearly specified but the other section has no fire-class call-out. Both sections must meet the requirement; a gap in the spec is a gap in the correction letter.

The official code

California Building Code (CBC) Section 1505.1 — Minimum Roof Fire Classification

Read the source →

Common questions

Does CBC 1505.1 apply to reroofing projects, or only new construction?
It applies to both. Any reroofing project that involves replacement of the roof covering must meet 1505.1. You cannot reroof over a Class B or unrated existing material and call the new material compliant unless the new product itself carries the required rating and is installed as a complete listed assembly. Under CBC 1505.1.2, replacing more than 50% of the roof within one year brings the entire roof covering under the requirement, and any covering applied in a repair must itself be at least Class C (Class A in fire hazard zones and WUI areas). Check your local amendments for stricter thresholds.
What is the difference between Class A, B, and C roof ratings?
The classes reflect how well the roof covering resists fire spread and ember penetration. Class A offers the highest resistance and is the most common requirement in California's wildfire-prone areas. Class B provides moderate resistance and is acceptable in some lower-risk zones. Class C provides light resistance and is the minimum allowed in most non-fire-hazard areas. The testing is done under UL 790 or ASTM E108 standards, which measure flame spread, burning brand resistance, and intermittent flame exposure. In practice, most modern asphalt shingles achieve Class A with the correct underlayment, so specifying Class A usually does not add significant material cost.
Is a Class A shingle still Class A if I skip the underlayment?
Almost always no. Most Class A shingle assemblies achieve that rating as a system: shingle plus a specific underlayment type (commonly a fiberglass-reinforced or fire-resistant felt) over a specified deck. Strip out the underlayment or swap it for a non-listed product and the listing does not apply. The ICC-ES evaluation report for the shingle will list the approved underlayment options. If you are re-using an existing underlayment on a partial reroof, confirm it matches the spec. This is a common gotcha on reroof corrections: the shingle carries a Class A label but the assembly does not.
My project is not in a WUI area. Do I still need Class A?
Not automatically. Outside of WUI areas and fire-hazard severity zones, CBC 1505.1 allows Class B or Class C depending on construction type and occupancy. However, many California cities have adopted local amendments that require Class A across the board regardless of FHSZ status. Before assuming Class C is enough, check the city's adopted amendments. Orange County cities in particular often have stricter local requirements. A quick call to the plan-check counter or a review of the local code adoption matrix for your city will tell you the floor requirement.
How do I find out if my property is in a Fire Hazard Severity Zone?
Use CAL FIRE's online FHSZ map at fire.ca.gov. Enter the address and the tool will show whether the parcel is in a State Responsibility Area rated as Moderate, High, or Very High. Also check with your local fire authority for locally designated fire hazard zones under Local Responsibility Area (LRA) jurisdiction. Both SRA and LRA designations can trigger the Class A requirement. Some properties sit right on the boundary, so verify with coordinates rather than a rough address pin if the result looks borderline.
Can I use a wood shingle roof and still meet 1505.1?
It depends on the class required and the product listing. Untreated wood shingles and wood shakes do not meet Class A or B requirements on their own. Pressure-treated or fire-retardant-treated (FRT) wood shakes can achieve Class B or, with specific assemblies, Class A. Many California jurisdictions in WUI areas prohibit wood shingles and shakes entirely regardless of treatment, citing local amendments or WUI chapter requirements. Check both the 1505.1 fire class requirement AND the California Wildland-Urban Interface Code (Title 24, Part 7) for your project before specifying any wood roofing product.

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