Drywall suppliers can deliver the unwieldy panels almost anywhere—even with a crane through second-story windows. Without the hassle of hauling, that makes drywalling a new room or recovering a damaged wall a reasonable do-it-yourself project—with just a few stumbling blocks.
Here are some of the false steps and how to fix them, or better yet, avoid them altogether.
The wrong framing. Wet lumber (over the acceptable standard of 19 percent moisture content) can wreck even the best drywall job. Finished seams and spackled nail heads give the appearance of smooth plaster to start. But as wet lumber dries out in he wall it can twist enough to pop nails and crack open joints between panels.
The wrong panels. Standard panels work on most walls. But water-resistant panels (normally green-tinted) include an asphalt mix in the gypsum and a chemical in the surface paper to stand up better in high-moisture areas like kitchens and baths. Another special type, fire-resistant panels, increase the amount of time wallboard stays intact when exposed to fire. They offer a better safety margin than standard panels in furnace or utility rooms—and may be required by code.
The wrong fasteners. You can use drywall nails to hang wallboard. And if the supporting lumber is dry and stable the heads probably will hold the panels tightly without popping. But for considerably more holding power, use threaded drywall screws. Aside from the extra strength, screws leave a small, uniform dimple in the drywall surface that's easier to spackle than a nail head.
Incomplete nailing. If you discover loose or sagging panels during installation, press firmly on the panel while driving home extra nails or screws. Don't rely on the fastener to pull the panel into place, particularly on ceilings. If you don't have enough helpers to hold the panel tight to ceiling joists while nailing, build an I-shaped brace, called a deadman, to help support the panel.
Unprotected corners. Drywall corners that protrude into the room are vulnerable to damage. A covering of paper tape and spackle is fine for appearance sake, but doesn't offer the extra strength of corner guard- an L-shaped metal strip that covers the drywall edges. Corner guard also serves as a guide that makes spackling corners a lot easier.
Raised joints. Bulging seams, called crowing, can result when taping compound is painted before it dries. Because it's obvious when compound is dry (it turns a light yellow color and powders under sanding), painting too soon is easy to avoid. More often, the swelling is caused by using too much compound under the joint tape, or by leaving large, compound-filled gaps between panels. The remedy is to sand down the crowns taking care not to scuff the drywall paper too much. To prevent crowning, fit drywall panels together without gaps and use only enough compound in the embedding layer to seat and smooth over the tape.
Tape bubbling. Unless compound is spread thoroughly over the seam between panels, dry spots can be left where the paper tape does not make contact- and they're likely to bubble later on. The key is to spread the embedding coat of compound evenly, and, when smoothing the tape in place, to watch for a complete and uniform color change. With continuous contact, the dry, light-colored tape darkens as it soaks up moisture from the compound. To repair a bubbled seam, use a sharp utility knife to cut away the dry paper and fill the damaged area with compound. Where bubbling pops up in many areas on the tape, the best bet is to remove it, sand off excess compound and start again.
Tape ghosting. Dark streaks over panel seams can appear soon after a new wall is painted. It's usually a subtle ghosting, but enough to see individual panels instead of one smooth surface. On DIY jobs, the most common cause is over-sanding. After three coats of compound, and a lot of sanding each time to smooth and even out the "mud", the joint may be so scuffed that it sucks excess moisture out of the paint—more so than surrounding areas that have a smooth paper surface. That creates a dull streak, most noticeable in white paint. Pros don't encounter this problem because they apply compound so smoothly it requires only occasional, touch-up sanding. For do-it-yourselfers, the solution is to sand sparingly, and if you can't help leaving a scuffed up joint, apply an extra coat of primer with a dry roller before the finish coat.Copyright © 2014, Los Angeles Times