The logo uses graphical text to spell out “DensDeck” in blue and green with a registered trademark symbol. The line below, starting at the second D, says “Prime Roof Board” in smaller, black text. The line above has the smaller white letters “GP” in a blue triangle with an extra small point at the bottom middle, and “Georgia-Pacific” in black text next to it.
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TOPIC 01

What is a Cover Board

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Chapter 01: The Risks of Leaving a Cover Board Out

How a cover board can help you mitigate risks.

This video tells you what can happen without a cover board in your roofing system.
Chapter 02: The main function of a cover board

Why use a cover board?

A cover board is a rigid component in a low-slope roofing system used to enhance durability and resiliency. Its key function is to protect your roof from damage.

A glass-mat gypsum cover board can help your roof stand up to fire, wind uplift, hail and punctures.

Where does it go?

A cover board is typically installed below the waterproofing membrane and above the insulation.
 
Glass-mat gypsum cover board can also be installed in the “roof board position” at the bottom of the roofing assembly. Here, it would protect the roof from internal fire within the building. This could help prevent the roofing system from becoming additional fuel.

A graphic shows commercial roofing system layers with annotations pointing out the Cover Board while the Membrane, Insulation, Substrate Board and Classified Steel Deck is isolated and grayed out.

Cover board options and comparison

Did you know that system manufacturers require a cover board for a 30-year roof? That’s why several types are available. See the differences in your options below. 
On a green background a chart compares cover board types across (5) categories: Cover Board, FM-Classified for VSH* (Very Severe Hail), Thermal Barrier, Noncombustible (Per ASTM-E136) and Ease of Use (Does not require special tools to cut). On the side, OSB/Plywood (Wood) has checks for Cover Board, and FM-Classified for VSH* (Very Severe Hail). HD ISO (High Density Foam Insulation) has checks for Cover Board and Ease of Use. Gypsum (Fiberglass mat rigid substrate) has checks for all (5) categories. Cement Boards has checks for Cover Board, Thermal Barrier, and Noncombustible (Per ASTM-E136). The asterisk states, “Consult RoofNav for FM-Approved and VSH assemblies with DensDeck® Prime and DensDeck® StormX® Prime Roof Boards.
Chapter 03: Building up the system

Common membrane choices

A graphic shows commercial roofing system layers with annotations pointing out the Membrane, while the coverboard, Insulation, Substrate Board and Classified Steel Deck are isolated and grayed out

A roof that can stand up to high winds, heavy rain and severe hail starts with a strong, durable membrane. 

EPDM – (Ethylene Propylene Diene Terpolymer)

A resilient, synthetic elastomer. Available in black and white, in a variety of widths and two thicknesses, 45 and 60-mil. It can be installed either fully adhered, mechanically attached or ballasted, with seams sealed by liquid adhesives or specially formulated tape.

TPO – (Thermoplastic Polyolefin)

A reflective, white roofing material made primarily from recycled rubber. Can be fastened, attached or ballasted. Must be installed in dry conditions due to the heat adhesion seaming process. Material quality varies drastically among manufacturers, which may cause price variability.

PVC – (Polyvinyl Chloride)

A durable, long-lasting, reflective, white plastic monomer. Flexible and resistant to moisture, wind, fire and chemicals. Available in a range of widths and thicknesses from 50 to 80-mil.

MOD Bit – (Modified Bitumen)

A durable, flexible material made of asphalt combined with either polymerized rubber (SBS—styrene-butadiene-styrene) or plasticized polymers (APP—atactic polypropylene). It is then reinforced with fiberglass to create a waterproof membrane. Usually installed from rolls directly onto the substrate via an adhesive. The material may be heat-welded, cold-adhered, or in some cases, self-adhered or mechanically attached.

Chapter 04: The Benefits of Gypsum

All it takes is a single ember

Building owners probably aren’t thinking about roof damage before installation. But you can make sure they’re prepared for the worst.

Whether it’s from a neighboring building or faulty electrical wiring, commercial building fires can escalate quickly. Using noncombustible roofing materials like gypsum can help mitigate the spread of fires that cause damage, injury and loss of life.

Discover How to Prepare Your Roof with a gypsum cover board to help you mitigate risks.

A large burning ember is in the foreground with smaller embers scattered on the perimeter. The roof of a large commercial building is shown below. The tops of semi-trucks can be seen in parking spots next to the building. Graphic text overlay says: Non-residential building fires have increased by 27% from 2013 to 2023. The 2022 national estimates for non-residential building fires and losses were: 129,500 total fires, 140 total deaths, 1,300 total injuries, $3,741,200,000 in dollar losses.

SOURCE:
1 Nonresident Fire Estimate Summaries – Nonresident building fire trends (2013-2022). U.S. Fire Administration (page last reviewed Dec. 2024). https://www.usfa.fema.gov/statistics/nonresidential-fires/

Test your knowledge

Topic Quiz: Roof protection education

The logo uses white graphical text to spell out “DensDeck” with a registered trademark symbol. The line below, starting at the second D, says “Roof Board” in smaller text. The line above has the smaller black letters “GP” in a white triangle with an extra small point at the bottom middle, and “Georgia- Pacific” in text next to it.
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