Gypsum wallboard, so common today, was an innovative and crucial component of the post-World War II construction boom. Though it was developed decades earlier (USG Corp.'s famous trade name Sheetrock first appeared in 1916), the paper-covered, nearly rock-hard panels were a perfect fit for mass production.
The prewar standard was strips of wood lath topped with three coats of plaster -- a painstaking job that often took weeks. Wallboard was less expensive, easier to install, needed no lath and required no extended drying time, thus the term "drywall."
USG, the country's leading manufacturer, has made more than nine billion panels, and today the material is used in 95 percent of new homes. Pros apply it at an incredible pace, but do-it-yourselfers working more slowly -- and winter is the time to work inside -- can handle the job following these 12 tips.
• Buy the right panels. Most rooms call for 1/2-inch-thick drywall with a plain paper surface over the gypsum core. But some areas rate special types, sometimes required by code.
Type-MR has a green and sometimes a blue surface due to treatment with moisture-resistant chemicals. The panels are often used in kitchens and baths and as a backing for ceramic wall tile. (Use cement-based backerboard in showers.) Type-X, treated to increase fire resistance, may be used in furnace rooms and in common walls between house and garage.
• Select economical sizes. Most do-it-yourselfers install 4-by-8 sheets on end. That works in rooms with standard ceilings, but creates a floor-to-ceiling joint every four feet. Pros use the longest possible sheets to minimize seams, and install wall panels horizontally to leave one long joint at waist level that's easier to spackle.
• Arrange delivery and storage. Wallboard is heavy (about 55 pounds per sheet), awkward to handle and easy to damage before it's hung. You need to find a safe place to pile it, on its edge. On jobs with narrow halls and stairs, a good boom-truck operator can maneuver loads so you can pull in panels through large windows -- even on a second floor.
• Make straight cuts. It's wise to use a straightedge guide for your drywall knife, especially on long cuts where you need to create a true edge. Many pros use a 4-foot metal T-square.
• Use the best fasteners. The old-fashioned method is to use sharp-pointed drywall nails pounded in with a hammer. The drawbacks: bent nails, hammer head gouges from mis-hits and nailheads that pop through drywall compound and need repair.
It's easier and better to use drywall screws set with a portable drill. The benefits: more holding power, no gouges, a small, uniform dimple that's easier to spackle, and no nail popping.
• Fasten panels completely. Press firmly on panels while driving nails or screws. Don't rely on fasteners to pull panels into place. If you don't have a helper to hold ceiling panels while nailing, build an I-shaped brace, called a deadman, for extra support. On big projects, consider renting a mechanical panel lifter.
• Protect corners. Drywall corners that protrude into a room are easily damaged. Paper tape and compound work well enough elsewhere, but these edges require the extra strength of corner guard. The L-shaped metal strip creates a neat, strong edge and is easy to spackle.
• Check the surface. Before spackling, sweep a metal taping blade or other straightedge across the surface. If it dings against a raised nail or screw head, stop to properly sink the fastener. If not, the protrusion will create gullies and ridges in your finishing compound.
• Use clean taping blades. Drywall compound dries quickly, particularly in flakes and gritty bits on the edges of metal taping blades. If you don't clean them frequently and thoroughly, even a small piece of grit can drag through compound as you smooth it, creating a furrow in the surface. Then you have to dig out the grit and start again.
• Avoid tape bubbling. Beat this problem by spreading a smooth, even coat of compound over seams. Then fully embed and smooth out the paper tape cover.
If you don't see uniform darkening as the dry tape starts to soak up moisture from the compound, pull it off, add more compound and try again. Dry, light-colored spots indicate that the tape is not fully embedded and will probably bubble as you add finishing layers of compound and paint.
• Avoid joint crowns. Raised joint seams result when too much compound is added, and sometimes when panels have gaps along the seams. Prevent crowning by fitting (but not forcing) panels together snugly, and by using a wide taping blade that rides on adjacent wall surfaces to keep the taped seam flush.
• Prevent seam ghosting. Pros conceal seams and fasteners by applying wide, smooth swaths of compound that need only a light sanding. Naturally, do-it-yourself-ers tend to spend more time erasing mistakes.
It's okay to smooth out defects in compound. But don't over-sand the drywall paper nearby. It leaves a scuffed surface that sucks excess moisture out of paint and creates slightly furry dull spots. On some do-it-yourself jobs you can see the grayish, ghost images of every over-sanded seam -- even under two coats of paint.
