Drywall as a building material didn’t become widely used until after world war two during the 1940’s and 50’s. Due to its low cost and ease of installation drywall is now used in almost every residential home, and commercial business. Since the introduction of drywall in the 40’ & 50’s there have been several advancements in the production and application of drywall. Drywall (the generic term) is known by several different names such as Sheetrock (brand), gypsum board, plasterboard, wallboard and gypsum board. Now day’s drywall now comes in various lengths, thickness and special uses.
The most commonly used drywall is Regular drywall. These panels are 48 in. wide and come in a variety of lengths from 8 ft. to 16 ft., are available in four thicknesses (5/8 in., 1/2 in., 3/8 in. and 1/4 in.), each with specific applications (and framing requirements).
Five-eighth-inch drywall is the thickest regular drywall available and provides the best single-layer application on walls and ceilings over wood and metal framing. The panels provide greater resistance to fire and deaden sound better than the other thicknesses; and because the panels are stiffer, they are more resistant to sagging. Five-eighth-inch drywall can be used on walls and ceilings with framing members (wall studs and ceiling joists) spaced up to 24 in. on centre (o.c). If you install (or “hang”) the panels parallel to ceiling joists, the joists should be no farther apart than 16 in. o.c. to prevent sagging. If you hang 5/8-in. panels perpendicular to ceiling joists, a water-based texture can be applied only if the ceiling joists are 16 in. o.c. or closer (again, to avoid sagging).
Half-inch drywall is the most commonly used drywall in both new construction and remodelling. It is usually used as a single layer over wood or metal framing, but it can be installed in two layers (with staggered seams) to increase fire resistance and sound control. The framing requirements for 1/2-in. drywall are the same as for 5/8-in. panels. If the framing is farther apart than the recommended spacing, wood or metal furring strips can be attached across the framing to the specified on-centre spacing.
Three-eighth-inch drywall was initially used to replace wood lath as a backing for plaster. When drywall first became popular, 3/8 in. was widely used on walls and ceilings in new construction, but it was eventually replaced by the more durable 1/2-in. drywall. Today, 3/8-in. drywall is used mainly in repair and remodelling work to cover existing surfaces or as a backing for panelling. It is also used in double-layer applications. The maximum distance between framing members on walls and ceilings is 16 in. o.c. For installation on studs and joists that are more than 16 in. o.c. apart, use a double layer of 3/8-in. drywall with adhesive applied between the two layers.
Quarter-inch drywall is a lightweight panel that is used to cover old walls and ceiling surfaces in remodelling jobs or for sound control in double-layer or multilayer applications. When hanging 1/4-in. drywall over old plaster or drywall, adhesive is used between the old surface and the new drywall in combination with screws to help strengthen the panels and reduce sag. The thin panels are too weak to install in a single layer over bare studs or joists without backing. Regular 1/4-in. drywall is easily bent and can be used to form curved surfaces with long radii (5 ft. or more) if applied dry, or shorter radii (3 ft. or more) if applied wet.
Commonly called green board or blue board due to its light green or blue paper face it is designed to withstand high humidity and low levels of moisture. Moisture resistant drywall is mainly used to cover bathrooms, the bottom 4 feet of a laundry or utility room or the wall behind a kitchen sink. Moisture – resistant drywall should not be used in a wet or high – moisture areas, such as a shower enclosure or wall just above a tub unless it will be covered with ceramic tile or a tub surround. Moisture – resistant is installed just like other types of drywall and can be finished and painted.
The term fire resistant means the ability of a wall or ceiling above covered with drywall to contain a fire. The fire resistant rating for each thickness is measured in intervals of time 45 minutes for ½” panels, 60 minutes for 5/8” panels and 120 minutes for ¾” panels.