Choosing the right types of drywall is the key to most speedy building projects. A little over a century ago, the laborious process of applying plaster to lath was the only way to create smooth-finish interior walls. The development of drywall — made of gypsum compressed between sheets of paper — not only significantly sped up the building process, it also brought the construction and renovation of interior walls within the reach of talented do-it-yourselfers.
Other than by brand, drywall varieties are limited in terms of size and thickness. By far, the most important consideration is your local building code. Most codes require fire-resistant drywall for walls that separate an attached garage from a residence and for garage ceilings with habitable rooms overhead (multifamily housing can have additional requirements such as fire-rated wallboard). Codes can also call for thicker drywall when studs are far apart or when a thick coating is to be applied. Moisture-resistant drywall may be required in bathrooms, around sinks or in pool areas. Generally, meeting or exceeding code is not only a legal necessity and a requirement for insurance, but good common sense.
Types of Drywall
Depending upon building codes and specific applications, the primary options are standard or specialty drywall.
Standard drywall is used for most general interior building applications. The most common thicknesses are 1/2-inch and 5/8-inch, and the most common size is 4 feet x 8 feet, although longer or wider sizes are available. Because most drywall seams will need to be covered with a combination of joint compound (“mud”) and tape, which then require multiple passes to create a smooth finish, using the largest size of drywall that requires the fewest seams is helpful. That choice, however, must be balanced against the difficulty of handling larger (and, consequently, heavier) boards. Apart from size, the other choice to make is between square-edge and tapered-edge drywall; tapered-edge is designed to accommodate seam taping and is the most commonly used variety. Square-edge drywall is used when a coating is intended to be applied without taping; if you decide to apply a plaster coating, you may want to choose “blue board,” which has a paper coating that helps the veneer to adhere.
Some thinner sizes of drywall are made for ceiling applications — they are easier to lift overhead. But keep in mind that if you plan any specialty ceiling finish such as popcorn or stucco, a heavier board will be required. Thin (usually 1/4-inch) drywall is also made for walls that curve; certain types are made to be flexible (for arches, for example) and can be applied when wet to make applying the curve easier. There is also a new class of ultralight drywall with a greater strength-to-weight ratio that is rapidly gaining popularity for being less strenuous to carry, but not all building codes have caught up with this new technology, so check before purchasing.
As discussed above, code may require that fire-resistant drywall (also referred to as “Type X” or “Perlite”) be used in certain instances. Although it may sound worthwhile to use it throughout a house, in reality, the fire-retardant effect inside a home would have little additional benefit unless all interior doors were also fire doors — generally an unnecessary expense.
Moisture- and Mold-Resistant Drywall
Recommended for bathrooms and other high-moisture areas, moisture-resistant drywall (also called “green board” for its most common color) is treated to stand up better in areas prone to dampness while allowing covered surfaces to “breathe,” thus avoiding mold build-up. For areas exposed to the most water, such as shower enclosures, an alternative product called cement board is recommended (and sometimes required). Cement board, as the name implies, is made of cement mixed with fibers and is considerably heavier than drywall; it cannot be as easily cut with a jigsaw as standard drywall.
Other commonly available types of drywall are impact-resistant and soundproof (“quiet board”). They are more commonly used in commercial and institutional construction but are widely available in small quantities if you have a residential need they can fill.