Understanding your roof fire rating and what it means

A fire near your home is a nightmare scenario, but such events are actually quite common here in the Valley. Every New Year’s Eve and Independence Day, errant fireworks accidentally set neighborhood trees ablaze, threatening surrounding homes. It’s important for your home’s roof to protect the rest of the structure when that happens. In this article, we’ll review what roof fire rating is, the origin of these ratings, and what classification your roof likely has.

Why are roof fire ratings important?

It’s unheard of today in the United States, but there once was a time when cities feared what homeowner-started fires could do. In 1871, the Great Chicago Fire killed 300 people and left 100,000 more homeless. The 1906 San Francisco earthquake was devastating, but most of the damage was actually caused by the fires started by ruptured gas lines. Phoenix has even seen its share of devastating fires throughout its own history.

What changed?

First, big city fire departments became more organized and more sophisticated, moving from volunteers to trained professionals. New infrastructure, such as fire hydrants, were installed to make fighting residential fires more efficient. But, most importantly, new building codes came into effect that dictated how buildings were constructed and what standards they needed to meet for fire resistance.

Today, this includes your roof, which often needs to shield the rest of the home in the event of a neighboring home on fire or a nearby tree that has caught ablaze.

A tile roof on fire, highlighting the importance of roof fire rating and testing.

In the event of a fire, a Class A roof is in the best position to resist fire getting into the attic until fire personnel arrive.

Understanding fire rating

Let’s start by discussing who decides what the particular “fire rating” of a material is. That’s typically a third-party, independent safety company. Here at KY-KO Roofing, our Owner’s Pride Guarantee promises that we only use high-grade roofing materials tested and approved by Underwriters Laboratories (UL, LLC). UL and similar companies put roofing materials and products through rigorous, scientific fire testing to determine how different materials stand up to fire exposure. They then assign a rating to those materials: A, B, C, or unrated.

In layman’s terms, your roof’s fire rating can be understood as:

Roofing Material + Underlayment Material + Any Additional Treatment = Roof Fire Rating

For example, a certain type of roof shingle might be a Class C material, but if the right underlayment is used and there is additional flame retardant added to the shingles during manufacturing, the entire roof’s fire rating may be Class A.

So, what do each of those “classes” mean?

  • Class A: The highest resistance to fire. Typical Class A roofs are those with concrete or clay roof tiles; metal roofs; or those using fiberglass shingles.
  • Class B: The second-highest resistance to fire. Typical Class B roofs are those with shingles that contain fire retardant chemicals.
  • Class C: The second-lowest resistance to fire.
  • Unrated: The lowest resistance to fire, or no fire resistance.

What kind of fire rating does your roof have?

  • Tile Roof: Many homes here in the Valley have tile roofs. That choice may have been made because of neighborhood aesthetics, but it’s also a good thing in terms of fire safety. Clay, concrete, and sandcast tile are all highly resistant to fire and heat, and have a Class A rating. Fire has a difficult time penetrating the tile to the underlayment and the attic below.
  • Foam Roof: Similarly, most foam roofs are considered Class A. Foam roofs are made of multiple layers to protect the underlayment and roof structure.
  • Shingle Roof: Shingle roofs can vary in terms of their fire rating, but the most commonly used fiberglass asphalt shingles typically are Class A. Organic shingles are more likely to be Class C by default, but, as noted above, the right underlayment and treatment can raise that classification to Class B or Class A.

What does this mean for your new roof?

First, you should only work with a roofing contractor that uses high-quality, UL-approved materials like we do here at KY-KO Roofing. Without that testing and verification process, the material’s fire resistance is effectively unknown. You’re, well, playing with fire.

One of the things that KY-KO Roofing does differently is our detailed roofing installation process, which has three phases overseen by an experienced roofing project manager. Proper installation is a major part of ensuring that the roof fire rating actually lives up to its billing in the event of a fire, which is why we focus on quality at every step of the job.

If you need a new roof here in the Phoenix metro area, call us for a free roofing checkup from our professional roofers. We’d be happy to discuss our materials and installation process in greater detail with you.