Gypsum board, for both interior and exterior construction, comes in a variety of? formulations, thicknesses, sizes and types. Principally made of a gypsum plaster mixed with additives and sandwiched between a top and bottom layer of paper, it can also be referred to as drywall, plasterboard, wallboard, sheetrock, LAGYP, gyprock or gib board. Standard thicknesses range from 0.25 to 0.75 inches, with the 4 x 8-foot outer dimension being the most common. A single manufacturer typically produces many different gypsum board formulations on the same production line in up to 30 different plant locations.