The fast version
A Class A fire rating is the highest available level of fire resistance for a roof assembly. It comes from a specific lab test (ASTM E108 and UL 790) that an independent testing lab runs on the full roof system, not on the tile or shingle alone. Class A means the assembly resisted flame spread, repeated flame exposure, and a flaming wood block placed directly on the surface. Concrete and clay tile reach Class A naturally because the tile itself is non combustible. Class A shingle systems exist too, but they only stay Class A if the underlayment and the deck meet the spec.
The Palisades and Eaton fires of January 2025 reset what every LA homeowner thinks about roof safety. In the neighborhoods where flying embers traveled miles ahead of the flame front, the homes that survived almost always shared one thing: a Class A fire rated roof system, properly installed.
Class A vs Class B vs Class C: what the letters actually mean
| Rating | What the system survives | Where accepted in LA |
|---|---|---|
| Class A | A 12 inch by 12 inch flaming wood block on the surface for over 90 minutes. Flame spread under 6 feet. Multiple flame exposures with no breakthrough to the deck. | Required in all fire severity zones (very high, high, and moderate) under California Title 24 Chapter 7A. |
| Class B | A 6 inch by 6 inch flaming wood block. Flame spread under 8 feet. Fewer flame cycles. | Not accepted in any LA fire severity zone. Used only in unzoned areas. |
| Class C | A 1.5 inch flaming brand. Less rigorous flame exposure overall. | Lowest level. Not accepted in any LA County brush zone. |
The practical reading: in LA County, if your home sits in a designated fire severity zone, code requires Class A. Most insurers in 2026 also require Class A regardless of zone designation. See our guide to tile vs shingle in Southern California for the material level fire comparison.
What the test actually measures
The Class A rating comes from three separate tests that the full roof assembly has to pass on the same panel.
Test 1 Intermittent flame
A propane burner cycles on and off against the roof, simulating the flame contact a house gets from burning vegetation nearby. A Class A assembly takes 15 cycles without flame penetrating to the underside of the deck.
Test 2 Spread of flame
A continuous flame at the panel edge measures how fast fire travels across the surface. Class A allows under 6 feet of spread.
Test 3 Burning brand
A 12 inch by 12 inch piece of wood is set on fire and placed directly on the roof. Class A means the assembly resists ignition, the wood burns out, and no flame penetrates the deck below. This is the test that simulates the flying ember problem that destroyed so many Palisades homes in 2025.
The word that matters most: system
Class A applies to the assembled system, not the tile. The rating includes the deck, the underlayment, the fasteners, the tile or shingle on top, and the way they are installed together. Swap any one component for a lesser one and the rating drops.
The single biggest misunderstanding homeowners have about Class A is thinking it applies to the tile or the shingle. It does not. A Class A tile installed over a Class C felt underlayment is no longer a Class A system. A Class A shingle installed over an old water damaged deck is no longer a Class A system. The lab test treats the whole sandwich. The code inspection should too.
When American Roofing Pro specifies a Class A tile system in a brush zone, the spec includes the tile, the underlayment (typically a fire rated cap sheet or a synthetic with a Class A listing on the assembly), the eave closure to keep embers out from under the first row, and the ridge and hip detailing. Each component is named in writing before the job starts.
Tile is automatically Class A: here is why
Concrete and clay tile are non combustible. The material itself cannot catch fire, and the air gap that naturally forms under the curved profile of tile reduces heat transfer to the underlayment during an ember storm or surface flame. That is why tile assemblies almost always test out as Class A.
This is not the case with wood shake (Class C at best, banned in LA County brush zones since the 1990s) or with some older felt underlayment shingle systems. Tile carries the rating by default. The question for tile homeowners is not whether the tile is Class A, but whether the underlayment beneath it is still in good shape, and whether the eave and ridge details are blocking ember entry the way they should. Our tile roofing service page covers the install scope in detail.
Underlayment matters as much as the tile
A 30 year old tile roof might still look perfect on top while the underlayment beneath has degraded past its Class A listing. If the underlayment is original felt from a 1990s install, it has likely lost most of its fire resistance. In a 2025 ember storm, the tile might survive but the system has dropped a rating class.
This is the case for a tile lift and re-lay. The existing tile gets carefully removed, the deck inspected, a modern Class A underlayment installed, then the original tile relayed with new fasteners. The system is restored to current Class A standards without the cost of a full replacement.
We recommend a Class A underlayment review every 20 years on any tile roof in a fire severity zone. The roof might pass a visual inspection while quietly being underlayered by a 30 year old fire risk. A roof inspection with a tile lift on a representative section is the way to verify.
California Title 24 Chapter 7A: who has to have Class A
Chapter 7A of the California Building Code applies to all new construction and most re-roofs inside designated Fire Hazard Severity Zones. The zones in LA County include:
Very High Fire Hazard Severity Zones (most stringent, ember resistant venting and Class A required):
- Hollywood Hills
- Bel Air
- Pacific Palisades
- Topanga Canyon
- Calabasas
- Hidden Hills
- Malibu hillsides
- Glendale foothills
- La Crescenta
- Altadena
- Sierra Madre
- Northridge hillsides
- Verdugos
High and Moderate Fire Hazard Severity Zones (Class A required, ember venting requirements vary):
- Granada Hills
- Chatsworth
- Woodland Hills (hillside)
- West Hills (hillside)
- Brush adjacent neighborhoods in the SFV and foothills
If your home sits in any of these zones, your re-roof permit application requires Class A documentation. The roofer must provide the manufacturer's UL or ICC listing reference at permit time. Permits without it do not get approved. See our guide to roofing permits in Los Angeles for how permitting works.
What Class A looks like on flat and low slope sections
Many LA homes are not pure tile from edge to edge. Mediterranean and contemporary builds typically pair a main tile roof with flat or low slope sections over additions, attached garages, covered patios, and second floor decks. Mid-century homes often have entirely flat roofs. ADUs added under the 2020 California regulations are almost universally flat. Every one of those flat sections has to meet Class A independently if the home is in a fire severity zone.
The roofing material that does this work on a flat roof is modified bitumen, sometimes called mod bit. It is a heavy asphalt based membrane reinforced with plastic or rubber and a polyester or fiberglass mat. It rolls out flat across the roof surface and adheres to a base sheet or directly to the deck. When the fire resistance is built into the membrane chemistry, the product is labeled with FR at the end of the product name. Without that FR label, the system is not Class A and not allowed under Chapter 7A. Our flat roofing service page walks through the install scope.
APP vs SBS: what the letters mean
There are two chemical families of modified bitumen:
APP (atactic polypropylene). Plastomeric. Stiffer, higher heat tolerance, harder UV surface. Better for hot installs (torch and hot mop). Slightly more brittle in cold weather, but cold is rarely a factor in LA. APP products typically end in P in product names (Polyflex P, for example).
SBS (styrene butadiene styrene). Elastomeric. More flexible, better at handling building movement and thermal cycling, slightly more forgiving of substrate imperfections. Better choice for buildings that move (older wood framed homes, garages on settling slabs). SBS products typically end in V in product names (Elastoflex V, for example).
Both can reach Class A as a system. SBS is the more common LA residential choice because of the flexibility advantage on older homes. APP shows up more on commercial flat roofs where reflectivity and UV durability matter most.
Application methods: which one fits your project
The FR rating is the same regardless of how the membrane goes down, but the install method affects cost, lead time, neighbor friendliness, and whether the work can even happen at your address.
| Method | How it goes down | Pros | Cons |
|---|---|---|---|
| Torch applied | Open propane torch melts the back of the membrane to the substrate | Strongest bond, fastest install, lowest material cost | Open flame near framing. Restricted on many occupied residential addresses in Chapter 7A territory because of install fire risk |
| Hot mop | Kettle of molten asphalt is mopped down, membrane laid into it | Strong bond, no open flame at the roof itself | Smoke and odor. The ground level kettle is its own fire risk |
| Cold applied | Brush or squeegee adhesive bonds the membrane | No flame, no smoke, safer near combustibles | Slower install, higher labor, longer cure window |
| Self adhered | Peel and stick release liner, no adhesive needed at the roof | Cleanest. Allowed in nearly every occupied residential setting. Fastest in tight access | Higher material cost. Substrate has to be dry and primed correctly |
For most LA residential brush zone work, the right answer is self adhered SBS FR. It avoids the install fire risk that has caused house fires during torch down repairs in dry brush conditions, satisfies Chapter 7A as a Class A assembly, and does not require a torch permit.
The major FR system manufacturers approved for LA
The Class A modified bitumen FR space is competitive. Every manufacturer below offers systems that pass UL 790 and ASTM E108 and are listed in the CAL FIRE Building Materials Listing (BML) for use in Chapter 7A territory. There is no single best brand. We spec based on substrate condition, install method, slope, and warranty fit.
Polyglass
The first manufacturer with a low slope system listed in CAL FIRE BML. We install their Polyfresko G SBS cool roof rated FR cap sheet on most residential flat sections where Title 24 cool roof compliance also applies. For sub-tile fire protection we use their Burn Shield XFR underlayment line under clay, concrete, and metal in steep slope assemblies.
GAF
Liberty SBS series including Liberty SBS FR. Wide local availability. Long manufacturer warranty options.
Firestone Building Products
APP and SBS FR options, strong in commercial leaning residential builds.
Johns Manville
APP, SBS, and modified APP options with FR variants. Solid Class A documentation.
Owens Corning
Standard fire rated lineup, common in tract home re-roofs.
Henry Company
Cold applied and self adhered FR options, often paired with their adhesives in mixed material assemblies.
When the address is in a Very High Fire Hazard Severity Zone, we spec the system before we send the proposal so the permit reviewer can verify the CAL FIRE BML listing reference in writing.
XFR class underlayments: where modified bitumen meets tile
This is where modified bitumen technology bridges back into the tile world from earlier in this guide. Self adhered fire resistant underlayments built on the same SBS chemistry as flat roof FR membranes can sit directly under clay, concrete, metal, or composition shingle on a steep slope. These are sold under product names like Polystick XFR (Polyglass), Tiger Paw FR (GAF), and equivalents from other manufacturers. Each is engineered to bring the assembly to Class A even when the surface tile or shingle would not, on its own, be enough.
For a brush zone tile re-roof, the underlayment is what separates a Class A system from a system that quietly downgraded to Class B over time. The cost premium for an XFR class underlayment over a standard synthetic is typically $0.40 to $0.80 per square foot. On a 2,000 square foot home that is $800 to $1,600 added to the project. In a Very High zone it is not optional.
Cost addition for FR on flat sections
Adding Class A FR membrane on flat or low slope portions of an LA brush zone home typically adds:
| Scope | Size | Cost range |
|---|---|---|
| Self adhered SBS FR cap sheet replacement on a flat garage roof | ~400 sq ft | $4,200 to $7,500 |
| Full FR re-roof on an addition or ADU | 1,000 to 1,500 sq ft flat | $9,500 to $18,000 |
| Cover board upgrade (gypsum or perlite under the membrane for fire performance) | per sq ft added | $1.10 to $1.80 |
These get rolled into the tile proposal as line items when the home has mixed sections. We do not separately quote them after the fact.
How to check whether your flat section falls under Chapter 7A
Two ways to verify:
- The CAL FIRE FHSZ Viewer shows your address in a fire severity zone map. Any zone designation (moderate, high, or very high) triggers Chapter 7A on a re-roof permit.
- The LA Building and Safety Department permit history at your address shows what fire rating the last re-roof was permitted under. If the last work was before 2008, Chapter 7A did not exist in its current form and an upgrade is required at the next re-roof.
When in doubt, our written estimate names the fire severity zone for your address, the Chapter 7A system being installed on each roof section, and the manufacturer BML listing reference for each. That document goes to the permit office and into the homeowner photo report.
Beyond the tile: the ember entry points that defeat Class A
A perfectly installed Class A tile roof can still fail in a wildfire if embers find their way underneath it. The structures that survived the 2025 LA fires almost always had three things in addition to a Class A roof.
1 Tight eave closure
Open soffit vents and gaps under the first course of tile let embers blow into the attic during a Santa Ana ember storm. Closed eaves, ember resistant soffit vents, and a proper bird stop at the first tile row close this path.
2 Ember resistant attic vents
Standard ridge vents and gable vents are open paths for embers in a wildfire scenario. The 2025 update to Chapter 7A requires ember resistant vent products in all Very High Fire Hazard Severity Zones. We spec these as standard on every brush zone re-roof.
3 Sealed roof penetrations
Skylights, chimneys, plumbing vents, and HVAC penetrations are common ember intrusion points. Each one needs proper flashing and current code compliant detailing.
A Class A tile roof system without these three details is still vulnerable. With them, the system performs the way the rating promises. Our roof storm prep guide covers the homeowner side of brush zone readiness.
What Class A means for insurance in 2026
After the January 2025 fires, several California insurers exited the homeowner market or restricted coverage in fire zones. The carriers still writing policies are pricing Class A roof systems differently from anything else.
In 2026, a verified Class A roof system in a fire severity zone typically qualifies for the lowest available premium tier and is often a hard requirement for any new policy. The Tile Roofing Industry Alliance and CAL FIRE's defensible space guidance both list Class A as the baseline for insurable structures in brush zones.
If your insurer asks for documentation, we provide the manufacturer's UL or ICC listing reference plus a stamped permit close out card. That paperwork goes into the photo report we deliver after every install. See our insurance claim guide for the rest of the documentation picture.
Real cost for a Class A tile system in LA
For a typical 2,000 square foot single family home in a fire severity zone:
| Scope | What is included | Cost range |
|---|---|---|
| Class A tile lift and re-lay | Reuse existing tile. New Class A underlayment. Ember resistant venting. Updated eave closure and bird stop. | $22,000 to $34,000 |
| Full Class A tile re-roof | New concrete or clay tile. Full Class A system including all hot zone details. Manufacturer warranty on the new tile. | $42,000 to $78,000 |
| Class A shingle re-roof with brush zone detailing | Class A architectural shingle, Class A underlayment, ember resistant venting, sealed eave and penetrations. | $24,000 to $42,000 |
Pricing varies with tile selection, deck condition, access, and the specific brush zone detail requirements at your address. We provide a written number after an in person measurement, free of charge. See our LA roof cost guide for broader pricing context.
How to verify your roof is actually Class A
If you bought your home with the tile roof already in place, or your last re-roof was more than 10 years ago, there are three ways to verify:
- Pull the permit.Permits issued in fire severity zones after 1990 should show the Class A listing on file. The LA Building and Safety Department or LA County Department of Regional Planning keeps these records.
- Inspect the underlayment.A tile lift inspection on a representative section of roof can show the underlayment type and condition. If the underlayment is original felt from a pre 2000 install, the system has likely dropped below Class A regardless of what the original permit said.
- Get a written certification.We provide written roof certifications that include Class A confirmation when the system passes. This document is suitable for insurance and real estate transactions.
A Class A tile roof, properly maintained and verified, is the single most important fire safety investment in a brush zone home. The rating means something. Make sure the system on your house actually has it.