Keep moisture at bay with high-performance gypsum panels

Controlling moisture — whether from rain, snow, groundwater, humid air or water vapor — is critical to ensuring the long-term durability of buildings. Left unchecked, the slow creep of moisture can cause mold and bacteria growth, wood rot and insect infestations that diminish indoor air quality, shorten the building’s service life and reduce occupant comfort.

Gypsum board is well known for its fire-resistance properties and that’s the main reason it gained popularity as a reliable building material in the mid-20th century. But by the end of the century, product innovation had transformed gypsum board into a high-performance building material that could also help architects design durable wall assemblies that resist damage from moisture, mold and mildew.

National Gypsum Company offers a continuing education course titled High-Performance Gypsum Board for Today’s Buildings to assist architects in understanding the different types of high-performance gypsum boards and how to specify them. The course offers 1 Contact Hour of Health, Safety and Welfare Education and 1 GBCI General Hour.

This CEU course has five learning objectives.

1. Examine ASTM standards for installing fiberglass-faced gypsum panels and explain how these products protect against mold growth and moisture infiltration, ensuring a healthy indoor environment for occupants.
2. Illustrate how the physical properties of gypsum contribute to the effectiveness of gypsum panel products during a fire, ensuring the safe evacuation of building occupants.
3. Identify the importance of specifying products that provide dimensional stability and a substrate for constructing high-performance, resilient wall assemblies.
4. Demonstrate the durability and strength of fiberglass-faced gypsum products compared to paper-faced gypsum board, emphasizing their higher compressive strength.
5. Describe how sustainable gypsum panel products can contribute to the LEED rating system and promote healthier spaces for occupants.

The National Gypsum Continuing Education program provides online and in-person courses for the design and building community. Presented by the Construction Design Manager team, courses cover product applications, technical standards and industry trends. All courses qualify for AIA learning credits.

What’s the difference between paper-faced drywall and high-performance gypsum board?

Paper-faced gypsum board has been in use since 1917 and can be made of mined gypsum rock or byproduct gypsum made from the cleaning emissions of coal power plants. While additives to the gypsum core and paper facing provide mold and mildew resistance, moisture can still damage paper-faced gypsum boards if they get wet over a prolonged period of time.

High-performance gypsum panels are encased with fiberglass mat that make them moisture resistant, resulting in these high-performance characteristics:

• Inherently mold resistant
• Dimensionally stable under temperature and humidity changes
• Superior strength
• Superior fire resistance
• Withstand up to 12 months of exposure to typical weather conditions

How are high-performance gypsum boards tested for mold resistance?

Mold-resistant gypsum products are tested per the ASTM D3273,Standard Test Method for Resistance to Growth of Mold on the Surface of Interior Coatings in an Environmental Chamber.

• The gypsum panel is placed in an environmental chamber set to a relative humidity range between 95% and 98%.
• Mold spores are injected into the soil.
• After 28 days, the panel is scored on a scale of zero to 10.
• A score of 10 represents no mold growth — and fiberglass-faced gypsum products score a 10.

What applications are high-performance gypsum boards designed for?

High-performance products, such as those in the Gold Bond^® eXP^® family of products, are recommended for constructing durable wall assemblies anywhere moisture is a concern.

Exterior applications

Moisture-resistant drywall, such as high-performance fiberglass-faced gypsum panels, are a good option for any part of the building that will be exposed to weather during construction. That includes elevator and stairwell shaft enclosures, the building envelope and the roof.

Gold Bond Building Products, LLC, an affiliate of National Gypsum Company, manufactures high-performance products designed to withstand the rigors of everyday weather exposure and reduce the chance of moisture and mold damage.

• Gold Bond^® eXP^® Sheathing
• Gold Bond^® eXP^® Fire-Shield^® Sheathing
• Gold Bond^® eXP^® Shaftliner
• DEXcell^® Glass Mat Roof Board
• DEXcell FA^® Glass Mat Roof Board
• DEXcell FA VSH^® Glass Mat Roof Board

Interior applications

In addition to being moisture and mold resistant, high-performance fiberglass-faced gypsum panels can also solve many design challenges inside the building. They are a key element in durable wall assemblies.

• Gold Bond^® eXP^® Interior Extreme^® Gypsum Panel: Ideal for use in pre-rock construction. Also available in a Type X or Type C core.
• Gold Bond^® eXP^® Interior Extreme^® AR Gypsum Panel: A denser core and enhanced glass mat resists indentation and abrasion, making it best suited for high-traffic corridors.
• Gold Bond^® eXP^® Interior Extreme^® IR Gypsum Panel: A denser core has fiberglass mesh embedded in it that combines with an enhanced glass mat facer to resist indentations and impacts, making it a good option for hospital corridors and gyms.
• Gold Bond^® eXP^® Tile Backer: An enhanced moisture- and mold-resistant core encased in specially designed acrylic-coated glass mat facers that provide superior protection against moisture and humidity, making it ideal for bathrooms and shower rooms. Plus, it creates an integral water barrier, eliminating the need for a separate water barrier.

In addition, all of these products can be part of UL fire-rated designs.

Ready to get more out of gypsum board?

Take our High-Performance Gypsum Board for Today’s Buildings continuing education course to better understand the nuances of high-performance gypsum products. Contact the National Gypsum Construction Design Manager team, which brings a wealth of design and construction expertise, to schedule an in-person presentation.