Class A Fire Rated Roofs By: Wade Shepherd

Wildfires threaten homes every year throughout the United States. Most homes that catch fire are quickly and completely destroyed during a wildfire event. Firefighters may not be able to protect all the homes and winds will move and feed the fire quickly. One of the best ways to protect your home from wildfires is to “harden the structure” with a Class A fire rated roof. The highest rating achievable for a fire rated roof is Class A. The roof system is tested and rated, not just the roof cladding material. For example, although standing seam metal doesn’t burn, it does conduct heat. Therefore additional fire barriers beneath the steel panels are needed to achieve a fire classification.

Like most parts of the house, roofing systems must meet building codes and insurance requirements demanded by state laws and other relevant institutions. Fire ratings for roofs are offered as Class A, B, or C ratings with Class A offering the best fire resistance for severe fires. A Class B rating may be appropriate for moderate fire exposure and a Class C rating may be appropriate for mild fire exposure. As wildfires are becoming more frequent and intense and more homes are being built adjacent to wildland areas, fire resistant construction is becoming more and more important to prevent catastrophic destruction and loss of life as we’ve seen in recent years in California.

Class A certification requires a very stringent and rigorous test regimen. A product must be tested as part of a system as that system would be constructed. The system includes the roof framing, decking (plywood), underlayment and roof cladding. The product as part of the system must pass each series of the following tests: burning brand, intermittent flame and spread of flame. Four consecutive burning brand tests must pass, and both intermittent and spread of flame tests must be consecutive passes. Each of these tests are conducted with wind blowing the flames and burning embers into the roof system replicating what can happen in a severe wildfire with strong winds. Class B and C certifications are also available; however they are significantly much easier to obtain than Class A. Many roofing products require additional fire barrier materials beneath the cladding, which can be quite expensive, difficult to obtain or challenging to install. Concrete and Clay tile roofs have been among the best protection against fires for centuries. Tiles are non-combustible and insulate against heat and radiation and therefore do not require any additional fire barrier materials. Another susceptible point on a home is the attic vent that can allow embers into the vulnerable attic space causing the home to burn from the inside. Protect your home with ember resistant vents such as Brandguard Vents.

Boral Roof Concrete and Clay Tiles are Class "A" fire-rated. This is the highest fire-resistance rating for roofing as per ASTM E-108. Watch this test and see how Boral Roofs are able to withstand severe exposure to fire with out burning.


Created with an image by Hans - "fire flame barbecue"

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