Gypsum board and plasterboard are panel products used in building construction to finish interior walls and ceilings. These panels are also referred to as wallboard, sheetrock or drywall, but all of these names refer to the same material. Depending on where you live, the contractor or retailer may refer to these boards by several names, and this may be where the confusion over the difference often begins.
One Product with Several Names
The terms gypsum board and plasterboard do not usually refer to a different product. Often it is either the trademarked name used by the manufacturer or the term commonly used in a particular region when referring to drywall or gypsum panels. In the United States, the term gypsum board or drywall is often used, while plasterboard is the term more commonly used in Europe. Both terms refer to a board that is made of gypsum plaster sandwiched between heavy paper layers. The boards are typically manufactured in 4-foot-by-8-foot sheets of varying thicknesses with coatings that make them useful in different applications. For example, Type X drywall is fire-rated, meaning it has been treated with chemicals that make it more resistant to fire than regular drywall.
Types of Gypsum
Gypsum is a crystalline mineral that is naturally occurring in sedimentary rock formations. This material may also be synthetic, created as a by-product of industrial manufacturing processes using fossil fuels like coal. Both types of gypsum are chemically called calcium sulfate dehydrate because they are chemically the same. When making the gypsum that is used in panel products, naturally occurring gypsum rock is crushed into a powder. Synthetic gypsum is typically a fine ground damp material.
The use of the terms gypsum and plaster for the same material may be attributed to the manufacturing process. To ready gypsum for use in wall panels, gypsum powder, whether synthetic or natural, is heated to remove moisture in a process called calcination. This calcined gypsum is commonly called plaster of Paris or stucco and is the primary ingredient in gypsum plaster. Gypsum boards, or drywall, are made by combining this calcined gypsum with water and other additives to form a layered board. As the board moves along the conveyor during manufacturing, the calcium sulfate hemihydrate in the gypsum recrystallizes to its original solid state and the paper layers become chemically and physically bonded to the gypsum core.
The first gypsum board product was made in 1888, when Augustine Sackett sandwiched plaster of Paris between several paper layers, according to National Gypsum Company. It was later sold as Sackett Board. Over time, innovations in gypsum manufacturing and technology made a product that could be tailored to suit the needs of the structure it would be installed in. Fire- and moisture-resistant panels and lightweight sheets that curve or bend are some of the variations that are available today. The term plasterboard may have accompanied this first drywall product because of its plaster of Paris core. Gypsum board is used by manufacturers to more accurately describe what the panels are made of.