• Typical professional installation of drywall takes one to two days for most houses.Jupiterimages/Photos.com/Getty Images
  
  Gypsum board is the most common type of drywall used to build walls and ceilings. Gypsum board is essentially crushed and compressed gypsum adhered to paper. The product is easy to cut or size, lightweight and durable. The specifications for gypsum board include the materials used in the board as well as varying sizes and intended use.
  
  

Makeup of the Board

• Gypsum board is basically the combination of heated, crushed stone and paper backing. Gypsum is a type of quartz rock found frequently in sedimentary deposits. The stone is heated to 350 degrees Fahrenheit in an effort to remove the majority of water and liquids, according to the Gypsum Association. After heating, the crushed rock is mixed with water and other chemicals, pressed between papers, and dried. The chemicals allow the gypsum to recrystallize forming a sturdy and stable base compound.
  
  

Sizes

• Almost all gypsum board comes in 4-by-8 foot sheets. However, several manufacturers produce 10-, 12-, and 14-foot lengths of gypsum board. The boards are usually two sheets pieced together at the ends with a thin strip of paper. The width of the boards can vary from one-quarter of an inch to a full inch. The most common sized used on interior walls is 3/8-inch thick. The individual sheets can be joined using plaster and paper tape that adheres to the surface of the board creating a seamless transition between sheets. Cutting a gypsum board requires running a razor knife along one side of the board, bending the board at the cut line, and cutting the backing along the folded line.
  
  

Uses

• The most common use for gypsum is for interior walls and ceilings. Typically, 3/8 inch drywall is used as the initial covering for walls; 1/2 inch drywall is more common for ceilings, however. 1 inch drywall is used in partitions, hall ceilings, or other areas where high-fire resistance and a sturdier drywall is needed. 1/4 inch drywall, the smallest size available, is rarely used alone; the small size typically is used as a thin cover over existing walls. Drywall has excellent sound-dampening effects. Several contractors use the 1/4 inch drywall as a base material when constructing rooms that need sound proofing.