Drywall

Drywall is a common building material. It is also referred to as plasterboard or gypsum board or by its common trade names Sheetrock and Gyproc. It is composed of two thick paper sides with a slab of compressed gypsum between them. Sheet rock is used as wall and ceiling cladding material and typically scrwed or nailed to wood or metal studs, often set on 16-inch or 400 millimeter centers. Drywall is not weight bearing and is not suitable for floors. However it can add shear strength to a framed structure.

It is known as "dry wall" because it replaced lath and plaster, which was applied "wet".

Drywall has very little water resistance. When a leaky roof or condensation drips or wets drywall, the gypsum can dissolve away and leave just a layer of painted paper in its place. A more water resistant form has a water repellent coating on one of the paper sides. The coating is green and it is called green board. Green board is a cheap solution to backing tile in a bathroom. In a heavily watered area, such as a shower, it is recommended to use cement board or other substrates instead.

Drywall can also have a layer of aluminum foil on one side. This layer offers even more fire resistance and is often used in condominium construction. The foil layer severely limits the transmission of radio waves, such as Wi-Fi signals.

In North America, drywall is typically available as 4-foot wide sheets of various lengths from eight feet to fourteen feet. It comes in various thicknesses, most common being 1/2 inch (12.5 millimetres) as well as 3/8 inch, and 5/8 inch.