Do Roof Shingles Burn: Fire Risk, Materials, and Safety

Do Roof Shingles Burn is a common question among homeowners concerned about wildfire exposure, attic fires, or roofing material choices. This article explains which shingle types are combustible, how fire ratings work, factors that influence ignition, and practical steps to reduce roof fire risk.

Shingle Type	Combustibility	Typical Fire Rating
Asphalt Fiberglass	Low Combustibility	Class A or B
Asphalt Organic	Higher Combustibility	Class B or C
Wood Shakes/Shingles	Highly Combustible	Class C or None
Metal Roofing	Non-Combustible	Class A
Clay/Concrete Tile	Non-Combustible	Class A

How Fire Ratings Define Shingle Resistance

Fire ratings are standardized classifications that indicate how roofing materials resist external fire exposure. The three common ratings are Class A, B, and C, with Class A offering the highest resistance. Class A shingles are designed to withstand severe fire exposure from burning embers and flames, reducing the chance of roof ignition compared with lower-rated materials.

Testing for these ratings typically follows ASTM standards or UL protocols, examining flame spread, ember resistance, and burning behavior. Consumers should check manufacturer specifications and local building codes when selecting shingles for fire-prone areas.

Asphalt Shingles: Fiberglass Versus Organic

Asphalt shingles are the most widely used roofing material in the United States, and they come in two primary constructions: fiberglass mat-based and organic felt-based. Fiberglass asphalt shingles are less likely to ignite and commonly achieve Class A ratings because the fiberglass mat is noncombustible and the asphalt coating offers some flame resistance.

Organic asphalt shingles contain cellulose or wood fiber and are generally more combustible. They are older technology and are often rated Class B or C, making them a less desirable choice in wildfire-prone regions or where building codes require high fire resistance.

Wood Shakes And Shingles: Natural Look, High Risk

Wood shakes and shingles provide a traditional aesthetic but pose significant fire hazards. Made from cedar, redwood, or pine, wood roofing materials are inherently combustible and can ignite from wind-driven embers or direct flame contact.

Some treated wood products are available with fire-retardant treatments that can improve performance, but treatments may degrade over time and typically require re-treatment to maintain protection. Many jurisdictions restrict or prohibit untreated wood roofing in high-risk wildfire zones.

Non-Combustible Alternatives: Metal, Tile, And Slate

Metal, clay or concrete tile, and natural slate are noncombustible roofing materials that provide excellent resistance to fire. These materials are rated Class A and will not burn, making them strong choices for reducing roof ignition risk.

Metal roofs can also shed embers and resist heat transfer but require proper installation to prevent gaps where embers could enter. Tile and slate offer mass and thermal inertia but can be heavy and may need reinforced roof framing.

How Embers Ignite Roofs

Embers are the primary way wildfires ignite roofs. Small burning particles can travel miles on wind currents and lodge in roof valleys, gutters, or under shingles. Even Class A shingles can be compromised if embers accumulate in roof openings or combustible debris is present.

Key ignition points include gaps at eaves and soffits, unprotected vents, accumulated leaves, and flammable rooftop equipment. Addressing these vulnerabilities is crucial in defending against ember-driven ignition.

Installation Quality And Roof Design Factors

Proper installation significantly affects how shingles perform in a fire. Poorly sealed shingles, exposed nail heads, and improper underlayment can allow embers to reach combustible decking. Using fire-resistant underlayment, proper flashing, and tight roof transitions reduces the chance of ember penetration.

Roof pitch, junctions, valleys, and penetrations such as chimneys and vents are also critical. Steep slopes shed embers and embers are more likely to lodge on low-slope roofs or in valleys, so design choices matter when assessing roof fire risk.

Codes, Standards, And Insurance Considerations

Building codes in many U.S. regions, especially those prone to wildfires, require higher fire-resistance ratings for roofing. Local codes may mandate Class A or Class B roofs, and insurers often offer premium reductions for noncombustible materials.

Homeowners should consult local building departments and insurance providers before selecting roofing materials. Compliance with codes can affect eligibility for insurance, grant programs, and post-loss rebuilding requirements.

Practical Steps To Reduce Roof Fire Risk

Reducing the risk that roof shingles burn involves multiple actions: clear gutters, maintain a defensible space of reduced vegetation, screen vents, and replace combustible materials near roof edges. Regular maintenance and ember-resistant retrofits significantly lower the chance that roof materials will ignite.

• Install Class A roofing where possible.
• Use noncombustible underlayment and ember-resistant vents.
• Remove leaves and debris from gutters and valleys regularly.
• Create a 30–100 foot defensible space per local guidelines.
• Replace wood shakes or organic shingles in high-risk areas.

Retrofitting Existing Roofs For Better Fire Performance

Retrofitting options include adding mineral-surfaced underlayment, installing ember-resistant soffit and vent covers, and replacing vulnerable trim. Retrofitting can dramatically improve the fire performance of an existing roof without a complete replacement.

An effective retrofit strategy pairs material upgrades with maintenance and landscape modifications. Some homeowners prioritize replacing roofing material; others focus on sealing openings and removing combustible attachments like wooden decks adjacent to rooflines.

Fire Testing And Manufacturer Claims

Manufacturers provide fire-rating documentation and test reports. Look for listings with UL (Underwriters Laboratories) or ASTM test references and ensure the product’s certification applies to the specific assembly being installed. Claims such as “fire resistant” should be validated against official Class A/B/C ratings and supported by test data.

Be aware that product performance in tests assumes correct installation and specific roof assemblies; deviations in underlayment, deck type, or attachment methods may change outcomes in real fires.

Real-World Performance: Case Studies And Lessons

Wildfire analyses show that homes with Class A roofs and defensible space fare much better during ember storms. However, studies also demonstrate failures when embers enter attic vents or gaps. Holistic protection—combining noncombustible roofing, ember-resistant construction details, and landscape management—is the most reliable approach.

Communities that adopt comprehensive building codes and homeowner education programs tend to reduce structure loss during fires, underlining the importance of coordinated risk-reduction strategies.

Choosing The Right Roof For Specific Risks

Selection should factor in local wildfire threat, insurance incentives, budget, and desired aesthetics. For high wildfire risk areas, prioritizing Class A noncombustible materials like metal or tile is a prudent choice.

Where budget or historic preservation concerns limit options, consider fiberglass asphalt shingles with regular maintenance and ember-resistant upgrades to vents and underlayment as a compromise solution.

Resources For Further Information

Trusted sources include state fire agencies, the U.S. Fire Administration, NFPA guidance, and local building departments. Manufacturer technical data sheets and UL listings provide specific fire-rating evidence for products.

Homeowners in wildfire-prone regions should also consult local wildfire mitigation programs, insurance providers, and licensed roofing contractors experienced with ember-resistant construction.

Key Takeaways On Do Roof Shingles Burn

Roof shingles can burn under certain conditions, but the risk varies widely by material, installation quality, and surrounding vulnerabilities. Choosing Class A materials, maintaining clear roof areas, and sealing openings are effective measures to minimize ignition risk. A multi-layered approach that includes both material choice and defensible space provides the best protection against roof fires.