Roof Boards Provide Moisture Control

Use DensDeck® Prime and DensDeck® StormX™ Roof Boards to help fight moisture damage on your building’s roof.


Enhanced with EONIC™ Technology

Moisture has a huge impact on the lifespan of a roof—affecting the safety of a building, as well as the contents and people it houses. Water’s damaging effects can affect your building in a variety of ways, both incredibly obvious and utterly undetectable until large-scale damage is already done. But adding a high-performance gypsum roof board to your roof assembly helps increase its water-resistance regardless of the environment in your building’s location.

A well-designed roof assembly includes a high-performance cover board to help protect against weakened roofing caused by moisture intrusion.
A well-designed roof assembly includes a high-performance cover board to help protect against weakened roofing caused by moisture intrusion.

Doubling DensDeck® Roof Boards’ resistance to moisture, built-in EONIC™ Technology makes DensDeck® Prime and DensDeck® StormX™ Roof Boards the only boards on the market with manufacturing specifications that include 5% total water absorption resistance by weight and 1-gram surface water absorption performance on both sides of the board.*

* Based on published manufacturing specifications as of December 1, 2017.


From hailstorms to ongoing foot traffic to heavy equipment and tools, general maintenance and usage can weaken a roof’s foundational defense. Cracks or tears of any size in the roofing membrane can leave openings for water to makes its way inside the roof assembly and begin to do damage. DensDeck® Prime and DensDeck® StormX™ Roof Boards provide a durable layer of protection over the insulation.

Without a high-performance cover board situated between the roofing membrane and insulation to enhance the assembly’s durability against the environment outside, extra pressure from general wear and tear or accidentally dropped equipment can leave cracks or holes that expose the structure to future water damage:

  • Creating openings for water to infiltrate during stormy weather
  • Trapping bulk water inside with no easy escape
  • Potentially soaking into the delicate insulation, reducing its R-value, and potentially rendering it useless


Even without an opening for entry, significant temperature differences inside and outside a building can result in vapor drive—as water vapor moisture flows in or out to find balance. But a well-designed roof with a high-performance cover board in place can better resist water absorption as a result of condensation from vapor drive.

DensDeck® Prime and DensDeck® StormX™ Roof Boards can better resist water absorption that results from condensation from vapor drive, which otherwise results in droplets:

  • Transferring from high to low pressure and density, away from warmer areas to cooler ones
  • Leading to warm, humid moisture within the roofing assembly, depending on seasonal weather changes and geographical locale
  • Requiring thermal regulation to keep this scientific phenomenon under control


Once inside the roofing structure, trapped water can lead to mold and mildew growth in a matter of days—particularly on commercial buildings with low-slope or flat roofing designs. Often unseen until it has already grown, mold spores can lead to toxic air quality and health concerns for tenants. Unlike other roof boards made with organic materials, DensDeck® Prime and DensDeck® StormX™ Roof Boards are inorganic, meaning they won’t contribute food to support mold growth. Coated with fiberglass facers with an enhanced moisture- and mold-resistant gypsum core, both roof boards meet the ASTM D3273 standard for mold growth. Using a roof board made from organic materials—like other common HD ISO roof boards on the market—can provide a cool, damp trap for fungus to spread:

  • Creating the perfect breeding ground for algae and mold growth
  • Developing as quickly as 1-2 days after the initial water infiltration occurs
  • Eventually showing signs through the building’s internal ceiling in the form of light pink or brown rings of discoloration

NOTE: Moisture has a detrimental effect on every cover board, including DensDeck® Roof Boards and every effort should be taken to keep them dry before, during and after installation. Damage or reduction in performance resulting from exposure to more than an incidental amount of moisture is NOT covered by the limited warranty for DensDeck® Roof Boards. For additional information on installation guidelines and product warranty, please see Resources.

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