A Primer on Roof Fire Ratings

Winds carrying embers can reach your roof—which also happens to be the part of your home that’s most susceptible to catching fire—well before wildfires do. That’s why building codes, like roof fire ratings, usually require and take into account buildings that have a fire-resistant commercial roofing system.

Primer on Roof Fire Ratings

Fire Rating Classifications

A roofing material’s fire rating indicates its resistance to flames. In general, there are four classifications. These are:

  • Class A – Class A roofing materials have the highest resistance to fire and are highly recommended for commercial and multi-unit buildings in areas prone to wildfires.

  • Class B – Roofing materials with a class B rating should be able to withstand moderate fires with a maximum flame spread of 8 feet.

  • Class C – Class C roofing materials provide minimal protection against fires.

  • Unrated – Avoid using commercial roofing materials that are unrated. The lack of a fire rating means the roofing material didn’t even meet the requirements to be classified under Class C, the lowest fire classification rating.

Common Fire-Resistant Roofing Materials

Here’s an overview of the most widely used fire-resistant roofing materials:

  • Asphalt shingles – Thanks to their durability and affordability, asphalt shingles are the most popular material for residential roof replacement projects. Class A shingles can withstand exposure to fires for about two hours.

  • Metal roofing panels – Metal roofing panels are noncombustible and therefore highly resistant to fires. However, the type of underlayment installed can affect a metal roof’s fire rating.

  • Single-ply roofing – There are several reasons why single-ply roofing membranes are one of the most popular commercial roofing materials in the country. They’re highly resistant to fire and damaging ultraviolet rays, exceptionally durable and. if you’re trying to green, an eco-friendly roofing material.

To learn more about the fire classification ratings and your commercial roofing options, you can consult an experienced roofer.

Sully Jones Roofing has been offering professional roof repair and replacement services to San Diego County residents since 1952. To get a free inspection, call us at (619) 444-0150 or fill out this form. We serve homeowners in El Cajon as well as the surrounding CA communities.