Understanding the Fire Safety of Asphalt Roofs
Your roof is your home’s first line of defense against the elements, including fire hazards. If you’re considering installing or replacing an asphalt roof, you might be wondering: Are asphalt roofs flammable?
The short answer is yes, asphalt shingles are combustible, but modern roofing materials are designed with fire resistance in mind. In this guide, we’ll explore:
✔ How flammable asphalt roofs are
✔ Fire ratings and classifications
✔ Factors that affect fire resistance
✔ How to improve your roof’s fire safety
By the end, you’ll have a clear understanding of how to keep your home safe while still benefiting from the affordability and durability of asphalt shingles.
Are Asphalt Roofs Flammable?
Asphalt shingles are made of fiberglass or organic felt saturated with asphalt and coated with protective granules. Since asphalt is a petroleum-based material, it is combustible, meaning it can catch fire under extreme heat.
However, not all asphalt roofs are the same. The fire resistance of asphalt shingles depends on their fire rating and the materials used in your roofing system.
Fire Ratings for Asphalt Shingles
The ASTM E108 fire rating system classifies roofing materials into three categories:
| Fire Rating | Protection Level | Description |
| Class A | Highest Resistance | Withstands severe exposure to fire without igniting. |
| Class B | Moderate Resistance | Resists moderate fire exposure but may ignite under direct flames. |
| Class C | Lowest Resistance | Provides minimal protection against fire. |
💡 Most modern asphalt shingles have a Class A fire rating, meaning they are designed to resist fire spread for the longest time possible.
What Makes Asphalt Roofs Fire-Resistant?
The fire resistance of an asphalt roof depends on several factors, including the materials used in the shingles, underlayment, and decking.
Composition of Asphalt Shingles
Fiberglass Asphalt Shingles (More Fire-Resistant)
✔ Made with a fiberglass mat base, which is naturally fire-resistant.
✔ Typically comes with a Class A fire rating.
✔ Best option for homes in fire-prone areas.
Organic Asphalt Shingles (Less Fire-Resistant)
❌ Made with a wood pulp or cellulose base, making them more flammable.
❌ Usually Class B or C rated.
❌ Less common in modern roofing.
💡 Tip: If fire safety is a top concern, always choose fiberglass-based asphalt shingles.
Fire-Resistant Underlayment
Underlayment acts as a protective barrier between the shingles and the roof deck. Some underlayment materials can increase fire resistance, such as:
✔ Fire-rated synthetic underlayment
✔ Asphalt-saturated felt with a Class A rating
✔ Self-adhering modified bitumen membranes
Choosing a high-quality, fire-resistant underlayment can greatly enhance your roof’s safety.
Roof Decking Material
The decking is the foundation of your roof and plays a role in fire resistance.
✔ Plywood & OSB (Oriented Strand Board) – Standard choices, but they are combustible.
✔ Fire-Rated Plywood – A safer option that is treated with fire-retardant chemicals.
✔ Concrete or Metal Decking – Non-combustible options for maximum fire resistance.
Roof Slope & Design
🔥 Roofs with steeper slopes tend to be less vulnerable to fire spread, as flames have a harder time moving uphill.
🏡 Flat or low-slope roofs may be at a higher risk if embers land on them and ignite debris.
💡 Tip: Keeping your roof clean and free of debris reduces the risk of fire.
Common Causes of Roof Fires & How to Prevent Them
Even with fire-resistant materials, roof fires can still happen. Here are the most common causes and how to protect your home.
Wildfires & Wind-Carried Embers
🔥 Risk:
- Wind can carry embers up to a mile away, igniting flammable roofs.
✔ Prevention Tips:
- Choose Class A asphalt shingles for maximum fire resistance.
- Trim trees and remove dry leaves & debris from the roof.
- Install gutter guards to prevent buildup of flammable material.
Chimney & Fireplace Sparks
🔥 Risk:
- Sparks from a poorly maintained chimney can land on the roof and start a fire.
✔ Prevention Tips:
- Install a spark arrestor on your chimney.
- Have your chimney cleaned and inspected annually.
- Use only dry, seasoned wood in your fireplace to reduce sparks.
Electrical Malfunctions & Lightning Strikes
🔥 Risk:
- Faulty wiring in the attic can overheat and start a fire.
- Lightning can ignite a poorly grounded roof.
✔ Prevention Tips:
- Have a professional inspect your electrical system regularly.
- Install a lightning protection system to redirect strikes safely.
Rooftop Equipment & Solar Panels
🔥 Risk:
- Faulty HVAC units, solar panels, or satellite dishes can overheat and cause fires.
✔ Prevention Tips:
- Ensure proper installation and maintenance of rooftop equipment.
- Use fire-rated mounting brackets for solar panels.
How to Improve Your Roof’s Fire Safety
If you’re concerned about fire hazards, there are several ways to improve your roof’s fire resistance.
✔ Upgrade to Class A Fire-Rated Shingles – The most effective way to enhance fire safety.
✔ Install Fire-Resistant Underlayment – Adds extra protection against ignition.
✔ Keep Your Roof Clean – Remove dry leaves, pine needles, and debris.
✔ Trim Overhanging Trees – Prevents embers from reaching your roof.
✔ Use Non-Combustible Gutters & Flashing – Metal options reduce fire risks.
💡 Tip: If you live in a fire-prone area, ask your roofing contractor about additional fire-resistant materials and coatings.
FAQs About Asphalt Roof Flammability
Are all asphalt shingles fire-resistant?
No, only Class A fiberglass shingles provide high fire resistance. Older organic asphalt shingles are more flammable.
Can a Class A roof still catch fire?
Yes, but it will resist ignition longer, giving firefighters more time to respond.
How do I know if my asphalt roof is Class A rated?
Check the manufacturer’s specifications or ask a roofing professional for an inspection.
Prioritize Safety with Fire-Resistant Roofing
While asphalt roofs are flammable, modern Class A shingles provide strong fire resistance. By choosing the right materials, keeping your roof clean, and taking preventative measures, you can reduce fire risks and protect your home.
If you need expert advice or a roof upgrade, contact Gorilla Roofing today for a free consultation!
🏡 Class A Fire-Rated Asphalt Shingles Available
🔥 Fire-Resistant Underlayment & Installation
✅ Free Roof Inspections & Estimates
📞 636-295-1212
🌐 gorillaroofing.com