Residential construction widely relies on a variety of gypsum products such as gypsum boards, panels, finish compounds, and accessories. According to the Gypsum Association, the North American industry trade association of gypsum manufacturers, an average home in the United States uses about 200 sheets of 4-by-12-foot board (approximately 8,500–9,000 square feet) for walls and ceilings. While this usage and its fairly long history in North American construction may lead some to think that gypsum board is just another commodity product, the reality is that gypsum board and panels have evolved and progressed in the past few decades. Changes in building codes, the rise of green building programs such as LEED, and evolving construction practices have generated a need for a suite of specialized solutions. Gypsum product manufacturers have responded with an array of standard and high-performance products that many architects and builders can benefit from by being more knowledgeable about them. High-performance gypsum board in particular has truly taken this former commodity to the status of an innovative product, allowing wall and ceiling surfaces to help solve a variety of current concerns and design issues. For example, the most recent advancements can help address indoor air quality, enhanced sound control between spaces, better durability, and overall sustainability. This course will review some of the history and manufacturing of gypsum products, distinguish between standard and high-performance products and finishing levels, and focus on the ways these advanced products can be used for environmental and human health considerations.

All images courtesy of CertainTeed Saint-Gobain

From design through construction and use, standard and high-performance gypsum boards and panels are estimated to be used in 97 percent of residential construction for a high-quality, sustainable, interior finish solution.

Why Gypsum? A Short History

Naturally occurring gypsum is a mineral made from calcium sulfate with chemically combined water (CaSO₄ 2H₂O). As such, it is quite workable when mixed with extra water and will harden back to a rock-like state as the excess water not needed for chemical bonding is removed. Gypsum has been used in a variety of solid forms and mixed into plasters of different consistencies for thousands of years.

The earliest known use of gypsum in building construction appears to have occurred in 3700 B.C. It has been discovered that the Egyptian pyramid of Cheops used gypsum blocks and plaster applied over woven straw lath as part of the construction. It is notable that much of this construction is still intact some 5,700 years later, testifying to the strength and durability of gypsum. Other places in the Mediterranean are known to have used gypsum for buildings and palaces through the centuries. In the Middle Ages, it was used to make alabaster (a form of gypsum) that was used by sculptors.

During the late 1700s, the noted French chemist Antoine Laurent Lavoisier analyzed the chemical makeup of gypsum. His work and subsequent research by a group of his contemporary chemists helped with a better understanding of its properties. Meanwhile, the discovery and mining of huge reserves of gypsum found near Paris led to the widespread use of “plaster of Paris” as a building material, primarily for plastering wall and ceiling surfaces. During a trip to France around this time, Benjamin Franklin observed farmers using gypsum as a soil additive. He was so impressed by the idea that he began to enthusiastically promote it upon his return to America.

Throughout the 1800s, many gypsum deposits were also discovered in the United States. Following the lead of the French, its primary usage was agricultural at first. However, in 1888, the so-called “grandfather of the gypsum board manufacturing industry” Augustine Sackett teamed up with Fred Kane and developed Sackett board—plaster of Paris sandwiched between several layers of felt paper. Sackett boards did not necessarily provide a nice wall finish, but they did provide a more convenient and excellent plastering base compared to wood lath for wall and ceiling construction. Sackett patented his manufacturing process and opened several production facilities over the next decade so that by 1901, he was producing nearly 5 million square feet of board annually. In 1916, the original board was finally replaced with a paper-faced product that was ready to finish, and gypsum board, or “drywall” as we recognize it today, was born.

World War I brought new challenges for the country but also new growth in the use of gypsum board. The U.S. Army had an immediate need for temporary housing both in the United States and overseas for an increasing number of troops. But when a tragic barracks fire claimed the lives of several servicemen, gypsum boards quickly became the material of choice for its inherent fire resistance. Its increasing use also led to new technological improvements, including air entrainment for lighter-weight and less-brittle boards, along with evolving joint treatment materials and systems. By 1930, there was a growing demand and a high enough number of manufacturers that the Gypsum Association was founded in April of that year. Some of the association’s first tasks were to develop standardized fire-resistance testing for gypsum products.

Gypsum boards have been commonly used in residential construction of all types for decades and have evolved to include high-performance solutions to meet the demands of 21^st century homes.

During the 1940s, gypsum boards were being incorporated in both domestic and overseas military construction for its ease of installation and fire-resistive qualities. By 1945, the government had used approximately 2.5 billion square feet of gypsum board in a variety of buildings and locations. The time period immediately following World War II is well known for the housing boom that followed but it also helped fuel a shift away from domestic plaster use and toward gypsum board. At this time, about 50 percent of the new houses being built in America used gypsum wall board, while the other 50 percent were being built with gypsum plaster over lath. This is also the time period when type X gypsum board was introduced with specific fire-resistance ratings available.

The 1960s and 1970s found the industry focusing on expanding the use of gypsum board into commercial construction, concentrating in particular on apartment building and office tower design solutions. This was also the time that improvements developed in the products, particularly for different types of fire-resistance-rated systems. Concurrently, there was a recognition that gypsum could be created synthetically using the same chemical makeup as natural gypsum so that by the 1990s entire manufacturing facilities were devoted to that purpose.

From a rather humble beginning over a century ago, gypsum boards have become the interior finish material of choice, currently covering the interiors of 97 percent of the new homes constructed in the United States and Canada as reported by the Gypsum Association. Building on this tradition and development, the industry is steaming headlong into the 21^st century with more options and choices for design and construction than previously available.