There are three possible ways that homes can ignite: direct flame contact, radiant heat exposure, embers/firebrands or radiant heat exposure. Wind-blown embers can ignite combustible materials like wood shake roofs. The greatest danger to a home is an untreated wood shake roof or shingle roofing.
Roof covering fire ratings include Class A, Class B, Class C, and unrated. Class A provides the best performance. Asphalt fiberglass composition shingles, concrete and flat/barrel-shaped tile are all common Class A roof coverings. Certain materials can have a Class A “by assembly” fire rating. This means that additional materials must be added between the roof coverings and sheathing in order to achieve this rating. Aluminum, rubber and recycled plastic are some examples of roof coverings that have a “by- assembly” fire rating.
Roof coverings can be classified as either Class A, B, C, or unrated according to their fire rating. Unrated roofs are the most vulnerable. The most common unrated roof type is made with non-fire retardant treated wood shakes and shingles.
Asphalt fiberglass composition shingles, concrete or clay tiles are all common Class A roof coverings. Certain materials can have a Class A “by-assembly” fire rating. This means that additional materials must also be used between the roof cover and the roof sheathing to achieve the fire rating. Aluminum, certain fire-retardant wood shakes products, recycled plastic, and rubber are all examples of roof coverings that have a “by- assembly” fire rating.
If your wood shake roof does not have documentation from the manufacturer indicating the fire rating, it should be assumed that the roof is unrated.
This post was written by Ted Williams! Ted is the owner of A Old Time Roofing, one of the best roofing companies in Saint Petersburg, FL! Ted is a Master Elite Weather Stopper GAF Roofing Contractor, a double award winner of Best Steep-Slope Contractor from GAF and achiever of Master Elite Consumer Protection Excellence from GAF. He has been serving the Pinellas County area since 1978. Old Time Roofing has a tradition of quality workmanship, servicing residential and commercial properties.