Drywall changed the building industry when it came on the scene about a century ago. While it took a few decades for drywall to fully take root in home construction, this pre-sized wallboard eventually meant no more nailing of hundreds of lath boards and troweling of wet plaster.
Along with its many advantages, standard sizing is one of the drywall's best features. With each sheet of drywall, you know in advance its exact size, down to the millimeter. Predictable sizing allows builders and homeowners to plan their projects with complete accuracy.
Drywall Length and Width
The length and width of drywall sheets are usually in multiples of 4 feet—most commonly, 4-foot by 8-foot, 4-foot by 12-foot, or 4-foot by 16-foot sheets. Building codes often have specific requirements for the thickness of drywall sheets but not for the width and length. These are determined by the needs of the architect, builder, and client.
4-Foot by 8-Foot Drywall
The most common size of drywall is 4 feet wide and 8 feet long.
Since 1/2-inch thick sheets of 4- by 8-foot drywall tip the scales at 57 pounds, this size tends to be the biggest sheet that most do-it-yourselfers can carry and lift into place.
The 4-foot by 8-foot size allows for either vertical or horizontal installation. Typically 4 by 8-foot panels come attached in pairs—two sheets face to face, with paper strips binding the two sheets. Most people find it extremely difficult to carry these sandwiched panels by themselves, and they can be difficult to cut. For solo transport, you can pull off the binding paper to separate the panels.
4-Foot by 12- or 16-Foot Drywall
For tall or long walls, drywall is available in lengths of 12 or 16 feet.
One advantage of these longer sheets is that you can create a smooth vertical surface to meet higher ceilings, creating a smooth surface that is completely unbroken from floor to ceiling. 16-foot-long drywall, when installed horizontally on a wall, produces fewer butt joints than with 8-foot-long sheets. If you are intending to work with 16-foot lengths of drywall, you need to have several people on hand to help you with the installation.
2-Foot by 2-Foot Drywall
The 2-foot by 2-foot square of drywall is not a stock sheet size. However, cut-down pieces of drywall are often available at most home centers and especially at smaller local hardware stores. These small sheets can be useful for patching jobs or wall-boarding small nooks and alcoves.
Alternative Sizes of Drywall
When wall panels come in lengths and widths other than these multiples of 4 feet, they are usually not drywall panels but are instead cement board or a drywall alternative, such as DRIcor Smartwall.
While not common on the consumer market, 4-1/2-foot-wide drywall sheets can be special-ordered. They are not stocked in home improvement centers and are rarely used except by professionals.
Common drywall thicknesses are 1/4-inch, 1/2-inch, and 5/8-inch. Building codes do have some requirements when it comes to the thickness of drywall panels. The thickness required for each application is dictated by the building code.
Not a common thickness, 1/4-inch-thick drywall is used as a skimming (or double-wall) material for placing over an existing surface.
An existing textured ceiling, for example, can be covered over with 1/4-inch sheets rather than going through the mess and work of removing a texture.
These thin drywall sheets are also valuable when you need to install drywall on slightly curved surfaces. If the drywall is not quite meeting the curve, you can slightly dampen the drywall to make it more flexible.
Half-inch drywall panels are the standard thickness for interior walls, as well as ceilings. These panels are easy to carry and hang.
Even easier to carry are ultra-light 1/2-inch panels, which are 13 pounds lighter than conventional 1/2-inch drywall.
These panels are commonly used for ceilings or for walls that require a prescribed fire-resistant rating.
When installed on ceilings, 5/8-inch-thick panels are less susceptible to sagging between the joists than 1/2-inch panels. Adding popcorn texture or another type of heavy surfacing material can add to the weight problem, making 5/8-inch drywall a better choice for ceilings.
Some applications call for or allow multiple layers of drywall. In townhouses, for example, the shared walls between units may require double layers of 1/2-inch wallboard to create a very fire-resistant and sound-resistant wall. In ordinary residential construction, doubling up drywall thickness can reduce sound transmission and make for sturdier walls.
Thicker drywall may be required by code for any wall or ceiling covered with a texture or skim coat where studs or joists are spaced 24 inches on-center rather than 16 inches.
This thicker drywall is often called fire-resistant drywall. Common walls between residential living spaces and attached garages, for example, require a fire-resistant construction, as do furnace rooms. This fire resistance can also be achieved by installing multiple layers of thinner drywall panels.