Drywall panels are manufactured in standard sizes, such as 4 feet by 12 feet or 4 feet by 8 feet. With such large sizes, the panels are heavy and awkward to handle and often must be cut into pieces. The pieces must be fitted together and applied over the entire surface of walls, ceilings, soffits, shafts, and partitions, including any odd-shaped and small areas, such as those above or below windows.
Installers begin by measuring the wall or ceiling areas and marking the drywall panels with chalk lines and markers. Using a straightedge and utility knife, they score the board along the cutting lines and break off the excess. With a keyhole saw, they cut openings for electrical outlets, vents, air-conditioning units, and plumbing fixtures. Then they fit the pieces into place. They may fasten the pieces directly to the building’s inside frame with adhesives before they secure the drywall permanently with screws or nails. Often the drywall is attached to a metal framework or furring grid that the drywall installers put up for support.
When such a frame-work is used, installers must first study blueprints to plan the work procedures and determine which materials, tools, and assistance they will require. They measure, mark, and cut metal runners and studs and bolt them together to make floor-to-ceiling frames. Furring is anchored in the ceiling to form rectangular spaces for ceiling dry-wall panels. Then the drywall is fitted into place and screwed to the framework.
Drywall installers are often assisted by other workers since drywall is very heavy. Large ceiling panels may have to be raised with a special lift. After the drywall is in place, drywall installers may measure, cut, assemble, and install prefabricated metal pieces around windows and doors and in other vulnerable places to protect drywall edges. They may also fit and hang doors and install door hardware such as locks, as well as decorative trim around windows, doorways, and vents.
Drywall finishers, or tapers, seal and conceal the joints where dry-wall panels come together and prepare the walls for painting or papering. Either by hand or with an electric mixer, they prepare a quick-drying sealing material called joint compound and then spread the paste into and over the joints with a special trowel or spatula. While the paste is still wet, the finishers press perforated paper tape over the joint and smooth it to embed it in the joint compound and cover the joint line.
On large commercial projects, this pasting-and-taping operation is accomplished in one step with an automatic applicator. When the sealer is dry, the finishers spread another two coats of cementing material over the tape and blend it into the wall to conceal the joint. Any cracks, holes, or imperfections in the walls or ceiling are also filled with joint compound, and nail and screw heads are covered.
After a final sanding of the patched areas, the surfaces are ready to be painted or papered. Drywall finishers may apply textured surfaces to walls and ceilings with trowels, brushes, rollers, or spray guns.