An Introduction to Drywall
Available in an ever-growing range of types and sizes, drywall is the preferred surface for walls and ceilings in residential construction.
During the 1940s and 1950s, prefabricated drywall panels gradually replaced plaster as the material of choice for finishing interior walls and ceilings. The earliest drywall panels were used to replace the lath backing in plasterwork; they were narrow (16 in. wide) and only 3/8 in. thick. Today, drywall comes in a wide variety of lengths, thicknesses, and special-use materials. The low cost and the large, easy-to-attach panels make drywall the preferred choice over conventional plaster.
A sheet of drywall consists of a hardened gypsum core sandwiched between two layers of paper—a strong, smooth-finished paper on one side (the face) and a rougher, “natural” paper on the back (see the drawing “End View of a Drywall Panel”). The face paper is folded around the long edges, which are tapered slightly to accommodate joint tape and compound after the panel is installed. The ends of the panel are cut square and finished smooth, leaving the gypsum core exposed.
Plaster-and-lath construction adds a lot of moisture to a building, and plastered surfaces are traditionally left to dry for up to two weeks (depending on humidity, temperature, and airflow) before being decorated. By comparison, drywall has a low moisture content and the joint compounds used to finish the panels cover only a portion of the exterior, rather than the entire surface, so they dry in 24 hours or less—hence the name “drywall.” Drywall is known by many other names, as well, such as Sheetrock (a brand name), gypsum board, plasterboard, wallboard, and gypsum drywall.
Drywall provides excellent sound control, structural integrity, and fire resistance. It is easy to decorate and serves as a good base for paint, wallpaper, paneling, textured finishes, decorative fabric, and vinyl wall coverings. The generic term drywall refers to a number of different types of panels, each with characteristics that make it suitable for specific residential and commercial applications.
Types and Uses of Drywall
When most people think of drywall, they probably picture the standard 4×8 panel that has been in use since drywall first became popular. But this is by no means the only size or type of drywall available today. Panels come in lengths of up to 16 ft. and in 48-in. and 54-in. widths. A wide variety of special-use drywall is also available, including moisture/mold-resistant, fire-resistant, and abuse-resistant panels; 1/4-in. flexible panels; 1/2-in. high-strength ceiling panels; and foil-backed panels. There is also a lighter-weight drywall, and a new type of drywall that takes volatile organic compounds (VOCs) out of the air, creating healthier environments. In the sections that follow, I’ll guide you through the various types and their uses, the thicknesses and lengths available, and the framing specifications for each one. With this information, you’ll be able to make the right decision about which type of drywall to order when it comes time to plan a job.
Why Use Drywall?
Regardless of the type, all drywall panels have common characteristics that make them more suitable for wall coverings than plaster, plywood, and other materials.