Drywall, otherwise known as gypsum wallboard or by the very common trade name of Sheetrock, has replaced plaster as the most common wall surface in American homes. It is used as a backing for wall treatments such as wallpaper, fabric, tile, and wood paneling. Or it can simply be painted.

Drywall has the virtue of being easy and inexpensive to install. It is sold in 4-by-8-, 4-by-9-, and 4-by-10-foot sheets; the most common thicknesses are 3/8 inch, 1/2 inch, and 5/8 inch—though other thicknesses are available. Most residential construction utilizes 1/2 inch.

Standard drywall is subject to moisture damage. Drywall that is water-resistant is identifiable as such because it comes with a thick blue or green backing. It is a must for bathrooms, especially showers, because of the walls’ high exposure to moisture. Both the surface and core of water-resistant drywall are specially treated to protect against humidity. It is almost always used to back ceramic tile.

After purchasing drywall, make sure to store it flat and in a dry location until you’re ready to install it. Leaning it up against a wall or other vertical surface could cause it to bow or warp and the edges to crumble.

Drywall panels are fastened directly to wall studs or to furring strips applied over masonry surfaces using wallboard nails, wallboard screws, or, in some cases, adhesive. The joints between panels are hidden by wallboard joint tape and joint compound. In some cases, a texture of special topping compound is applied over the entire surface.