Gypsum board is also commonly known as drywall or wallboard. The product is a type of material used for walls and ceilings and has been utilized as such since the 1940s. This type of wall board is the most common used in homes throughout the United States. The primary ingredient in gypsum board is a mineral called gypsum, also known as hydrous calcium sulfate. When making gypsum board, the mineral is ground and then mixed with starch so that it adheres well. There are several types of gypsum board made and the type will determine what other ingredients might be added. Once water is added to the mix a slurry is laid between two think sheets of paper and set to dry in a kiln before they are cut into appropriate sizes.
Gypsum board is commonly used by contractors to close off walls and provide a solid wall or ceiling. The contractor uses nails or screws (known as drywall screws) to hold the gypsum board in place against the studs of the walls and ceiling. Once put in place most contractors use drywall tape and sometimes mesh corner pieces for all edges and corners. The contractor will then use drywall putty or cement to putty over all of the nails and rough places. When this dries the contractor will sand the putty down evenly, clean the wall of all dust and prepared for painting.