A Guide to Roof Fire Ratings

Residential roof repair and installation involve a fair amount of work. As the homeowner, you’re expected to know your way around various options as far as materials, looks, warranties and other factors are concerned. It’s safe to say you should do your homework before contacting a contractor.

Most homeowners will look at swatches, materials and the like before they make a decision. However, one of the most important factors that many homeowners neglect is the fire rating of the materials they consider. To help you avoid making that mistake, here is a rundown of the different fire ratings for roofing materials. 

Class A Roofing

Materials can be stand-alone or assembly-rated as Class A fire-retardant. Stand-alone materials include concrete tiles, slate, clay tiles and asphalt glass fiber composition shingles. Materials that meet Class A standards only in combination with other elements are known as assembly-rated. 

A material can achieve a Class A rating if it passes several tests:

• -Go through 15 cycles of a gas flame turned on and off without catching fire
• -Withstand two to four hours of flames before igniting
• -Keep its integrity after being subjected to a 12”x12”, 2000-gram burning brand
• -Experience a maximum flame spread of six feet

Reputable residential roofing contractors would be happy to tell you more about the Class A-rated products they carry. Make sure to ask them about fire ratings if you live in an area that’s prone to wildfires.

Class B Roofing

Roofing that’s rated as Class B should protect your home against exposure to moderate fires. The test is similar with Class A products, with a few exceptions. The flame spread is up to eight feet. The burning brand is 6”x6” and weighs 500 grams. The roof shouldn’t catch fire at least an hour after exposure. And it should resist the on-off gas flames for eight cycles.

There are common Class B-rated materials, such as pressure-treated shingles and shakes.

Class C Roofing

Light fire protection is what a material offers when it’s rated as Class C. Flame spread would reach 13 feet; the burning brand is only 1.5”x 1.5” and weighs only a fourth of a gram; it should last 20 minutes before ignition; and the gas flame on-off test is three cycles long.

Untreated wood shingles and shakes, particleboard and plywood are Class C. A good roofing installation company is highly unlikely to recommend Class C materials. 

Unrated Roofing

Avoid using unrated roofing materials. They are unrated because they couldn’t even pass the testing for Class C. They offer hardly any protection against fire, if at all. 

Reach out to Dior Construction for more about roof fire ratings and their significance to your home. Call us today at (833) 838-3467 or fill out our contact form to set an appointment. We would be glad to answer your questions in Essex County, NJ, and in other areas in New Jersey.