What is Drywall?
Like plaster, Gypsum is the primary ingredient in drywall. Gypsum is a soft white mineral that can be heated to produce plaster powder. Water (and other ingredients depending on the type of drywall) is added to make Gypsum slurry that is formed into sheets of drywall.
As it is poured and before it dries, gypsum slurry is wrapped with paper. The finished product is a panel of hardened gypsum in between two thin layers of paper.
In many respects, drywall is similar to plaster in its purpose and base material. One difference between the two is that the gypsum slurry is formed into pre-poured panels before installation, whereas plaster is spread directly in place.
Why is it called Drywall?
To understand why the term drywall became popular, it is best to contrast its application with that of plaster. Applying plaster involves spreading several layers of wet slurry across a substrate of wood or metal lath. In this sense it can be thought of as a “wet-wall” process. The contrast between wet plaster and dry panels of preformed Gypsum explains the use of the term drywall.