As an alternative to a week-long plaster application, an entire house can be drywalled in one or two days by two experienced drywallers, and drywall is easy enough to use that it can be installed by many amateur home carpenters. In large-scale commercial construction, the work of installing and finishing drywall is often split between the drywall mechanics, or hangers, who install the wallboard, and the tapers and mudmen, or float crew, who finish the joints and cover the fastener heads with compound. Dry wall can be finished anywhere from a level 0 to a level 5, where 0 is not finished in any fashion and 5 is the most “pristine”. Depending on how significant the finish is to the customer the extra steps in the finish may or may not be necessary, though priming and painting of drywall is recommended in any location where it may be exposed to any wear.
Drywall is cut to size, using a large T-square, by scoring the paper on the finished side (usually white) with a utility knife, breaking the sheet along the cut, and cutting the paper backing. Small features such as holes for outlets and light switches are usually cut using a keyhole saw or a small high-speed bit in a rotary tool. It is then fixed to the wall structure with nails or screws and often glue. Drywall fasteners, also referred to as drywall clips or stops, are gaining popularity in both residential and commercial construction. Drywall fasteners are used for supporting interior drywall corners and replacing the non-structural wood or metal blocking that traditionally was used to install drywall. Their function serves to save on material and labour expenses, to minimize call-backs due to truss uplift, to increase energy efficiency, and to make plumbing and electrical installation simpler.
Screws’ heads have a curved taper, which allows them to self-pilot and install rapidly without having to be punched through the paper cover. When finished driving, these screws are recessed slightly into the drywall. Screws for light-gauge steel framing have an acute point and finely spaced threads. If the steel framing is heavier than 20-gauge, self-tapping screws with finely spaced threads must be used. In some applications, the drywall may be attached to the wall with adhesives.
After the sheets are secured to the wall studs or ceiling joists, the installer conceals the seams between the sheets with ‘joint tape’ and several layers of ‘joint compound’ (sometimes called ‘mud’). This compound is also applied to any screw holes or defects. The compound is allowed to air dry then typically sanded smooth before painting. Alternatively, for a better finish, the entire wall may be given a ‘skim coat’, a thin layer (about 1 mm or 1/16 inch) of finishing compound, to minimize the visual differences between the paper and mudded areas after painting.
Another similar skim coating is always done in a process called veneer plastering, although it is done slightly thicker (about 2 mm or 1/8 inch). Veneering uses a slightly different specialized setting compound (“finish plaster”) that contains gypsum and lime putty. This application uses blueboard, which has special treated paper to accelerate the setting of the gypsum plaster component. This setting has far less shrinkage than the air-dry compounds normally used in drywall, so it only requires one coat. Blueboard also has square edges rather than the tapered-edge drywall boards. The tapered boards are used to countersink the tape in taped jointing whereas the tape in veneer plastering is buried beneath a level surface. One coat veneer plaster over dry board is an intermediate style step between full multi-coat “wet” plaster and the limited joint-treatment-only given “dry” wall.