Wildfires are becoming larger, faster, and more frequent.
Underwriters Laboratories (UL), a non-profit organization that tests and certifies building materials, specifies testing.
Roof coverings (also known as roofing material) must provide a degree of protection against flame penetration to the underlying deck and attic space without producing flying embers or slipping from their installed position in order to meet UL standards and receive a fire Class A, B, or C rating. Roofs that fail to meet this standard are deemed unrated. A Class A rating indicates the best type of roof for fire resistance.
Class A roofing materials have proven to be resistant to the most severe fire tests. They offer the best fire resistance as stand-alone roofing products, with excellent resistance to surface flame spread and no need for chemical treatments or additional underlying roofing materials.
Class B roofing materials have proven to be resistant to moderate fire exposure. To meet Class B requirements, some roofing materials may be infused with fire-retardant chemicals.
Only light fire exposure has proven to be effective for Class C roofing materials. Reconstituted wood products and untreated wood shakes are examples of Class C materials.
It is important to note that Class A, B, and C fire test ratings are for external fire resistance only; they have no bearing on how a roof will withstand an internal fire.
While a Class A-rated roof is essential for fire resistance, homeowners should also consider other property conditions to.