DensDeck® Prime and DensDeck® StormX™ help minimize the risk of rooftop fire damage.



The best way to protect the roof is to prepare for the worst by building the best. In the event of a fire, choosing the right high-performance roof board for your building can make all the difference in protecting the roof. But the materials used in the roof boards also make a difference. DensDeck®, DensDeck® Prime, DensDeck® StormX™ Prime Roof Boards are made from both gypsum and glass mat, both fire-resistant and noncombustible materials.


Whether the source of a fire is inside the building or out, it needs oxygen, fuel, and heat to progress. Combustible roofing materials can ignite and fuel a fire when exposed to the right conditions. But noncombustible materials may help starve and active fire by depriving it of additional substance to burn, while also blocking flames and heat from igniting adjacent layers in the roof. DensDeck®, DensDeck® Prime, DensDeck® StormX™ Prime Roof Boards are made from materials that will help enhance the fire resistance of the roofing assembly.

Side-by-side comparison shows that DensDeck® Prime and DensDeck® StormX high-performance roof boards provide better fire resistance than competitive products on the market.

Gypsum’s composition includes chemically combined water, adding natural fire protection from its very core. All gypsum (including DensDeck® Roof Boards) is comprised of 21% chemically combined, crystalized water and 79% calcium sulfate. In the event of a fire, this water gradually releases as vapor and remains inert up to temperatures as hot as 2,200o Fahrenheit. For building materials made with gypsum, this release of water can also help to slow the burning of organic materials in a fire. When waiting for the fire department to arrive, this can add valuable help in the fight to save a building.


The roof of the building is a crucial area that can either aid or halt continued fire development. Designing the roof with strategic board placement can help block heat and flames from reaching combustible components of the roof assembly from either direction.


Adding a roof board as a thermal barrier in your roofing system (attached directly to the roof deck) acts as a fire barrier. If the worst happens and a fire does break out in your building, the roof board helps to keep the roof assembly’s materials from adding to an internal fire’s fuel source.

diagram/illustrationDesigning your roofing system with a roof board in the cover board position (attached beneath the roof membrane) helps to keep embers from airborne neighboring flames from landing and igniting the roof.

For additional product fire, safety, and use information, go to or call 1-800-225-6119.

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