Different Drywall Thickness
Drywall comes in many different thicknesses. The two most common are half inch and five eighths. Here is a brief description of some common drywall thicknesses and their use.
¼ inch thick drywall
Quarter inch thick drywall is very flexible and for this reason it is sometimes used on curved walls. It is easily bent around large gradual curves but will crack if forced too much. Wetting quarter inch drywall can make it more flexible, allowing it to mold to even tighter curves. However, care is needed not to use too much water which can reduce the structural integrity of the panel.
Usually when using quarter inch drywall to wrap around curved walls or soffits, it is best to double the thickness by adding a second layer over top of the first. This adds strength to the wall. It also makes it easier to create, even, gradual curves.
⅜ inch thick drywall
Three eighths inch thick drywall is also very flexible and can also be used for bending around some curves. However, it is more often used to cover over old plaster or unsightly drywall walls. As plaster ages and the building settles, it starts to crack. A few cracks here and there can be fixed with drywall tape but if cracks develop throughout, drywall tape does not provide enough reinforcement. In that case, drywall can be used to laminate over top of the old plaster. Three eights inch thick drywall is perfect for this application. Drywall glue can be used to secure the drywall to the plaster. However, the layer of drywall on top is only as strong as the layer it is attached to. Therefore, it is always best when laminating, to use long screws that reach to the underlying studs.
Three eighths inch thick drywall is also used to laminate over top of cinder block and form poured concrete walls. Plastering is usually the preferred method of interior finishing over top of concrete or cinder block. However, since skilled plasterers are hard to find, some contractors have found success laminating over concrete using three eighths drywall. In this case drywall adhesive is generally your best option for securing the drywall. Once challenge is figuring a way to keep the drywall in place while the glue dries. You can use wooden bracing shoved against the opposite wall to achieve this. The key is to support the sheet of drywall evenly as the drywall adhesive cures.
½ inch thick drywall
Half inch thick drywall is the most popular thickness of drywall used in residential construction. Half inch thick drywall is used on most walls and even some ceilings. As long as the studs or floor joists are spaced no more than sixteen inches on center, half inch drywall provides enough rigidity to be used in most settings. Half inch drywall is less expensive than five eighths drywall and easier to handle. For this reason, it is the go to choice for residential construction.
There are types of half inch drywall that is specifically designed for used where the studs or floor joists are wider than sixteen inches apart. However, as a word of caution, if the type of drywall you are using is not specked for use on ceilings with twenty four inch on center floor joists, it will most likely sag. Usually thicker drywall is needed in those instances.
⅝ inch thick drywall
Five eighths inch thick drywall is by far the most commonly used thickness of drywall for commercial and industrial construction. Most municipal building codes require five eighths drywall in commercial settings and depending on the situation, fire rated five eighths may be required.
Five eighths drywall is stronger than half inch drywall and makes for stronger walls. It is also more rigid and for this reason can be used on ceilings where the floor joists are spaced twenty four inches on center. Five eighths drywall will not sag as easily and therefore holds up better even when used with heavy ceiling textures.
¾ inch thick drywall
Three quarter inch thick drywall is not used very often. Though only slightly thicker than five eighths, it is difficult to work with and more expensive. Three quarter inch thick drywall is usually only used in unique settings where an architect or engineer specifically directs its use.
Anything one inch or thicker
Drywall that is one inch thickness or more is rarely used. This thickness of drywall is considered specialty drywall and is only used as part of engineered controls for a building. For example, one or even two inch thick drywall may be specified for lining elevator shaft walls due to fire protection requirements. Drywall this thick is very difficult to work with and incredibly heavy.