Fire resistance is one of the most important considerations when choosing roofing materials. One of the big reasons for this is that there are a lot of different mishaps that could cause a fire on the roof. Lightning strikes have been known to do it, and so have drifting sparks and embers from things like bonfires, barbecues or even fireworks. Sparks from chimneys are a common cause of roof fires, and in some areas, wildfires are a threat. That’s why it’s wise to choose highly fire resistant roofing materials if possible. But which materials have the highest fire resistance ratings? Let’s take a look!
Underwriters Laboratories Fire Resistant Roofing Ratings
The key thing to look for in fire resistance ratings are those given by the Underwriters Laboratories. These ratings are given out as classes, Class A, Class B and Class C. Class C is the lowest of the ratings, which means that materials with this rating are effective against light surface fires, allowing flames to spread no more than 13 feet. Class B materials are rated for moderate fires, allowing flames to spread no more than 8 feet, and Class A materials feature the highest fire resistance, the least flammable of all, allowing flames to spread no more than 6 feet.
Another thing to be aware of is that there are technically two types of class ratings. The ratings described above are specific to the product, but there is also a “by assembly” class rating. A roofing product with a “by assembly” class rating is one that may not necessarily fit the criteria of one of the UL classes, but could fit the criteria when installed with other fire-resistant materials. For example, fire retardant wood shakes often have a “by assembly” rating, which means that they need to be installed with the recommended underlayment and other products to meet that rating.
What Underlayment to Choose?
In general, synthetics like Epilay’s Protectite line are a great choice because they often feature the Class A rating. All of Epilay’s synthetic underlayments have this rating, which makes them a great line of defense against fire hazards. And if you’re using a primary roof covering with a “by assembly” rating, then synthetic underlayment can help you meet the criteria to achieve maximum fire protection.
What About Other Roofing Materials?
When it comes to the primary roofing material—like shingles, steel or slate—there are a lot of great options that will give you the Class A fire rating you’re looking for. Fiberglass based asphalt shingles are probably the most popular option, and if they are combined with the right underlayment, then they can achieve a Class A rating.
Clay and slate tiles are two more great options. Both of these types of roofing systems are naturally fire resistant, and they’re thick, which also helps with fire resistance. Clay resists heat, and slate is durable, not easily chipped, which prevents flame from reaching structures below. Both are more expensive than asphalt shingles, but when installed correctly, they’ll offer a Class A rating, too.
Metal roofs should not be discounted, either. Corrugated steel is the most common choice, but there are tiled and shingled metal roofs, too. Quite often, since metal is a non-flammable material, it carries a Class A fire rating.
So there you have it! There are lots of great options that can be used together to create a highly fire-resistant roofing system. Between fire resistant underlayments and modern roofing materials, there’s no need to sacrifice aesthetics to create a Class A roof.