Rivagips BG Ltd

The name drywalling derives from drywall’s replacement of the lath-and-plaster wall-building method, in which plaster was spread over small wooden formers while still wet. In 1916, the United States Gypsum Company invented a 4′ x 8′ sheet of gypsum pressed between sheets of extremely strong paper, which they called „Sheetrock.“ Despite being used extensively at the Chicago World’s Fair in 1933-34, it was generally seen as an inferior alternative to plaster and did not catch on quickly. It gained popularity during World War II, when the war effort made labor expensive. It was reintroduced in 1952, and the suburban migration of the 1950s was fueled in part by the cheaper construction methods allowed by drywall.

As opposed 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 mudman, or float crew, who finish the joints and cover the nailheads with drywall compound.

Drywall is cut to size, using a large T-square, by scoring the paper on the front side (usually white) with a utility knife, breaking the sheet along the cut, scoring the paper backing, and finally breaking the sheet in the opposite direction. 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. Drywall is then fixed to the wall structure with nails, or more commonly in recent years, the now-ubiquitous drywall screws.

Drywall screws have a curved, bugle-shaped top, allowing them to self-pilot and install rapidly without punching through the paper cover. These screws are set slightly into the drywall. When drywall is hung on wood framing, screws having an acute point and widely spaced threads are used. When drywall is hung on light-gauge steel framing, screws having an acute point and finely spaced threads are used. 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 seams between drywall sheets are concealed using 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. For this application blueboard is used 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 drywall 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.