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Innovations in Residential Construction Using Advanced Gypsum Products

Gypsum products are no longer mere commodities; they now offer solutions for safer, healthier, more sustainable and eco-friendly buildings.

By Peter J. Arsenault, FAIA, NCARB, LEED AP

Continuing Education

Use the following learning objectives to guide your study of this month’s Continuing Education article.

Learning Objectives - After reading this article, you will be able to:

1. Understand the history of gypsum as a raw material and its significant usage in residential construction.
2. Comprehend the manufacturing process of both natural and synthetic gypsum products and their contributions to sustainability.
3. Explore the variety of high-performing, innovative gypsum products and their different finish levels contributing to green building designs.
4. Evaluate how gypsum products enhance green and sustainable design in any residential project.

Residential construction heavily depends on various gypsum products such as gypsum boards, panels, finish compounds, and accessories. According to the Gypsum Association, the industry trade association for gypsum manufacturers in North America, an average U.S. home uses approximately 200 sheets of 4-by-12-foot board (around 8,500 to 9,000 square feet) for walls and ceilings. Despite its longstanding use, gypsum board has greatly evolved over the past decades. The development of building codes, green building programs like LEED, and modern construction practices have driven the creation of specialized solutions. High-performance gypsum products now address vital concerns such as indoor air quality, enhanced sound insulation, durability, and overall sustainability. This article will examine the history and manufacturing of gypsum products, distinguishing between standard and high-performance variants and their benefits for the environment and human health.

All images courtesy of CertainTeed Saint-Gobain

Gypsum boards and panels are integral to 97 percent of residential construction, providing high-quality, sustainable interior finishes.

Why Gypsum? A Brief History

Gypsum, a mineral comprised of calcium sulfate with chemically combined water (CaSO4·2H2O), has been used for thousands of years in various forms. When mixed with water, it becomes highly workable and hardens as it dries, making it a valuable material for construction.

The earliest use of gypsum dates back to 3700 B.C. in the construction of the Egyptian pyramid of Cheops, utilizing gypsum blocks and plaster over woven straw lath. The remarkable durability of this construction, still intact after 5,700 years, highlights gypsum's strength. Throughout history, gypsum has been used in Mediterranean buildings and palaces and during the Middle Ages for alabaster sculptures.

In the late 1700s, French chemist Antoine Laurent Lavoisier analyzed gypsum's chemical composition. His work, along with that of his contemporaries, enhanced the understanding of gypsum's properties. The discovery of abundant gypsum deposits near Paris led to widespread use of "plaster of Paris" for plastering walls and ceilings. Benjamin Franklin later promoted gypsum as a soil additive in America after observing its use in France.

Significant gypsum deposits in the United States were discovered in the 1800s, initially used for agriculture. In 1888, Augustine Sackett developed plaster of Paris sandwiched between felt paper layers, marking the introduction of gypsum board. By 1916, paper-faced gypsum board emerged, giving rise to "drywall" as we know it today.

World War I saw a spike in gypsum board usage for temporary housing due to its fire-resistant properties. Technological advancements, such as air entrainment and joint treatment materials, were made possible. By 1930, the Gypsum Association was founded to develop standardized fire-resistance testing for gypsum products.

Gypsum boards have been extensively used in residential construction for decades, evolving to meet modern demands.

In the 1940s, gypsum boards were used in military construction for their fire-resistance and ease of installation. Post-World War II, the housing boom led to a shift from plaster to gypsum board in new homes. Type X gypsum board with specific fire-resistance ratings was introduced during this period.

In the 1960s and 1970s, the industry expanded gypsum board use in commercial construction, focusing on apartment buildings and office towers. Synthetic gypsum began production in the 1990s, leading to entire manufacturing facilities dedicated to this purpose.

Today, gypsum boards cover 97 percent of new homes in North America, with ongoing innovations enhancing design and construction options.

Gypsum Product Manufacturing

Understanding the production process of gypsum products is essential for appreciating their attributes. There are two primary methods for manufacturing gypsum products.

Natural Gypsum

Before the 1980s, nearly all gypsum used in production was naturally mined. Plants were located near significant natural gypsum sources. Today, reclaiming gypsum from recycled products allows plants to be situated closer to construction centers. Natural gypsum rock is crushed, heated to 350 degrees Fahrenheit (calcining), mixed with water and additives to form a slurry, and then fed between layers of paper on a board machine. The board is cut, dried in kilns, stacked, and transported.

Both natural and synthetic gypsum boards share chemical properties, making them suitable for construction and finishing.

Synthetic Gypsum

Since the 1990s, new gypsum board plants have utilized coal-fueled power to produce synthetic gypsum through flue-gas desulfurization (FGD). This process removes sulfur dioxide, creating calcium sulfate of similar quality to natural gypsum. FGD gypsum contributes to environmental cleanliness by promoting clean air and reducing landfill waste. The U.S. gypsum industry annually diverts nearly 8 million tons of FGD gypsum for board production.

Both natural and synthetic gypsum in boards are non-toxic and safe, meeting stringent quality standards. About half of the gypsum used in the U.S. is synthetic FGD gypsum. The paper facing on gypsum boards is typically 100 percent recycled, further reducing environmental impact.

Residential Gypsum Board and Panel Types

Various types of gypsum products are available, distinguished by how the gypsum cores are finished. Commonly, gypsum wallboard with paper facings is used for walls and ceilings. Some products feature glass-mat facings or other surface treatments for enhanced performance, known as gypsum panels.

Standard Gypsum Boards

Two main types of standard gypsum boards are used in residential construction:

• Common residential gypsum board: This standard gypsum board features a paper-facing and is typically ½ inch thick. It is used for single-layer interior applications in residential and non-fire-rated commercial construction. A lightweight version is also available.
• Fire-resistance-rated boards: Type X gypsum board assemblies must achieve at least a 1-hour fire resistance rating, typically requiring 5/8 inch thickness and specific installation details. This board contains non-combustible fiberglass fibers and additives for enhanced fire resistance, used in locations requiring fire-rated separations.

Type X gypsum board is used in residential construction for its fire-resistant properties.

For higher fire resistance, Type C gypsum board contains more glass fiber and an additive to prevent shrinkage during fires, achieving ratings of 2 to 4 hours.

High-Performance Gypsum Boards and Panels

High-performance boards and panels build on standard or fire-resistant boards with variations in core or facings for specialized needs:

• Moisture/mold/mildew-resistant gypsum boards: These boards have a moisture-resistant core and paper facing with additives to prevent mold, ideal for bathrooms and basements.
• Paperless drywall: Reinforced with fiberglass mesh, this board offers higher mold resistance and is used in high-humidity areas but not for direct water contact. Variations include fiberglass-faced backer boards for showers.
• Acoustic-control gypsum board: This multilayer board reduces sound transmission with a central layer of sound-absorbing polymers, suitable for reducing noise in residences.
• Indoor air quality gypsum board: These boards absorb VOCs like formaldehyde, chemically converting them into harmless compounds, improving indoor air quality.
• Abuse/impact-resistant gypsum board: Designed with face paper resistant to tears and cores that resist dents, this board is ideal for high-traffic areas like stairways and garages. It usually comes in 5/8-inch thickness with additional resistance to abrasion and impact.

Understanding the differences between standard and high-performance gypsum products aids architects and designers in selecting the best options for specific project conditions.

Installing and Finishing Gypsum Boards and Panels

The quality of gypsum board installation and finishing greatly impacts final results. ASTM C840 – 17a outlines standards for application and finishing of gypsum board, covering details like framing size, fastener spacing, cutting, installation, and on-site storage. This specification applies to various gypsum products and finishing materials.

ASTM C840 provides standards for proper installation of gypsum boards and panels.

The Gypsum Association’s GA-214-2015 sets recommended finish levels for gypsum boards and panels, developed with the Association of the Wall and Ceiling Industries-International (AWCI), CISCA, PDCA, and the Drywall Finishing Council. This guide updates standards to include modern products and outlines finish levels on a scale of zero to five:

• Level 0 finish: Unfinished gypsum boards or panels secured to studs or substrates without tape, joint compound, or accessories.
• Level 1 finish: Joints and corners embedded in a single layer of joint compound with excess compound removed. Tool marks and ridges are acceptable, and fastener heads and accessories are not finished.
• Level 2 finish: Joint tape embedded and smoothed with a thin layer of joint compound. Fastener heads and accessories are covered with one layer of joint compound.
• Level 3 finish: An additional coat of joint compound is applied to joints, fastener heads, and accessories for a total of two coats. All surfaces are sanded smooth.
• Level 4 finish: Used for flat paints and lightweight wall coverings. A third layer of joint compound is applied, and surfaces are smooth. For glass-mat panels, a skim coat may be necessary for a consistent surface.
• Level 5 finish: The highest level of finish requires a skim coat over the entire surface, ideal for semi-gloss or gloss paints and severe lighting conditions. This finish level should be clearly identified in construction documents due to its higher cost.

Choosing the appropriate finish level ensures the best final appearance, satisfying fire-resistance requirements and controlling project costs.

Sustainability and Gypsum Products

Gypsum products significantly contribute to sustainable building practices. Incorporating standard or high-performance gypsum products supports green building certification programs like LEED v4, The Living Building Challenge, and the National Green Building Standard. Contributions include:

Materials and Resources

LEED v4 emphasizes the availability of life-cycle assessments (LCAs) for certifying green materials. The Gypsum Association has developed product category rules (PCRs) and life-cycle assessments for gypsum boards and glass-mat panels, forming the basis for environmental product declarations (EPDs). Favorable LCA inputs include the use of recycled or reclaimed gypsum, 100 percent recycled paper facings, and minimal packaging for shipping. Gypsum products can be reused, recycled, or used as agricultural soil conditioners at the end of their life, enhancing their sustainability.

Gypsum boards and panels have green and sustainable properties contributing to better life-cycle performance and healthier indoor environments.

Indoor Environmental Quality

Programs like LEED, the WELL Building Standard, and the Living Building Challenge focus on human health in indoor environments. GreenGuard and DECLARE ratings, as well as health product declarations (HPDs), help specify healthy products. Gypsum products are inert and nontoxic, aiding in healthy indoor environments. Moisture-resistant or glass-mat boards prevent mold, adding to indoor quality. Acoustic control boards reduce noise, contributing to a peaceful environment.

Overall, gypsum boards, panels, and related products have a proven history of contributing to green and sustainable construction.

Conclusion

Gypsum products have evolved into a diverse range of standard and high-performance options, enhancing residential construction in North America. By selecting products that offer multidimensional performance, design goals can be met, construction can be improved, green building objectives can be achieved, budgets can be controlled, and the quality of life for building occupants can be enhanced.

Peter J. Arsenault, FAIA, NCARB, LEED AP, is a nationally known architect, consultant, continuing education presenter, and prolific author advancing building performance through better design. www.pjaarch.com, www.linkedin.com/in/pjaarch

CertainTeed drywall and finishing products deliver durability, acoustics, and indoor air quality solutions. To view our full portfolio of solutions, visit www.certainteed.com/drywall.

 

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