Drywall is a building material made from gypsum, sand, water, and other minerals. These materials are pressed together and sealed between layers of heavy paper to form a dense sheet that can range from 1/4 inches to 3/4 inches (6.35 to 19 mm) thick. Different types of drywall products are used to build walls, ceilings, and many other architectural features in homes and commercial structures.
The majority of drywall products are chosen based on budget and application. Thinner sheets of drywall are more affordable, but tend to be less durable and long-lasting. Thicker sheets or those with added features tend to hold up better, but come with a higher upfront cost. Choosing the correct drywall products can actually lead to cost savings in the long run however, due to a decrease in maintenance, repair, or replacement costs.
Builders can choose from several different types of drywall when constructing a home or building. Traditional drywall will work in almost any application, and has no added components to increase its cost. Fire-rated drywall, known as "Type X," contains perlite of vermiculite to help slow the spread of fire and minimize the risk of collapse or failure. Moisture-resistant drywall products, often called green board, are used in wet areas like basements, bathrooms, or kitchens to help prohibit mold and mildew growth.
For veneer plaster applications, builders can use plaster board or blue board in place of regular drywall. This material has a special coating on its surface to help plaster adhere to the board smoothly. Sound-rated drywall is used to reduce noise transmission through walls and ceilings, and may contain lead or metal foil to deflect sound waves. Lead-lined drywall products are used in hospitals and laboratories to protect occupants from X-rays and magnetic imaging machines.
Drywall installers must hang and finish these products to create the desired structure or design. Sheets of drywall are hung from wooden or metal wall framing members using drywall screws or nails. They may also be attached to ceilings or masonry walls using metal channel clips. To apply drywall to ceilings or upper wall sections, installers often use a piece of equipment known as a drywall lift, which secures the sheet of wallboard in place so that it can be fastened to the framing members.
After the drywall is hung, it must be finished using additional drywall products to create a smooth surface. First the seams between each sheet are sealed using drywall tape. The tape is then covered by a thick paste known as joint compound or drywall mud. After the mud has dried, the walls are sanded to smooth and even out the surface. Drywall installers may add layers of joint compound to create a textured look, or the walls can be left smooth for painting.