Roofing Material Fire Ratings

An exterior fire retardant treated shake roof has a stand alone class b rating.

Roofing material fire ratings.

Common underlying materials include a type 72 roll roofing material also known as 72 pound felt or 72 pound capsheet material and a panelized gypsum product called densdeck. Wood shake plywood or particle board roof are the most common roofing types listed as class c. Ul 790 underwriters laboratories roof fire ratings a b c tests. Fires that originate outside of the structure itself.

But by including a particular underlying material it can meet the requirements for a class a roof. Understanding roof fire ratings class a roofing. In a recent roofing column we focused upon technical information that could be found on roofing material wrappers that could verify compliance with various building codes. The maximum flame spread is 6 feet for a class a rated roof 8 feet for class b and 13 feet for class c.

The slope of the test specimen is preselected and since steeper slopes are more of a challenge due to melting material feeding the fire the rating applies to the maximum slope passed. Class a roofing is the preferred choice for any home but this type of roofing is particularly important if you live in an area that is prone to wildfires to achieve a class a rating the roof must be effective against severe fire exposure. Class c fire resistant roofing material. Class a does not mean grade a roofing systems are rated by realistic fire tests.