Gypsum board is now such a commonly used building material that it's difficult to imagine a construction project that doesn't use it somewhere. Most residential interior walls and ceilings are composed of framing and gypsum board; a very large portion of commercial interior walls use gypsum board; gypsum sheathing is frequently used in exterior construction; and area separation walls in townhouses and shafts for elevators and stairwells frequently are built using gypsum shaft liner board.
Gypsum board is also used in areas less considered, including exterior soffits and ceilings, grease ducts, roof underlayment systems, tiled areas and as a substrate for veneer or Venetian plaster. This popularity as a building product speaks to gypsum board's versatility, cost effectiveness and ease of installation. But gypsum board's current popularity also speaks to the promotion of the product that began as a major effort in the early '50s and lasted through the '70s.