Reducing Drywall Callbacks -

Continued

Corner Bead

The corner bead callback can look like someone drew a line with a sharp pencil about an inch in from the corner along the length of the outside corner bead. Or it can look kind of wrinkled, with some compound missing here and there, or be a slightly protruding ridge along the entire corner. Whatever the problem, metal corner bead is a real nuisance to repair. Maybe it's time to use something besides the old standard nail- or crimp-on metal bead. I have had excellent results with the newer mud- or tape-on corner beads (Figure 5).

Figure 5. Mud- or glue-on perforated vinyl corner beads that move with the drywall, not with the framing, eliminate bead pops and make ding repairs a snap.

Mud-on beads are usually made of plastic or metal that is covered with paper. Products include No-Coat (Drywall Systems; 888/662-6281; http://www.no-coat.com), Sheetrock paper-faced metal bead from USG (800/621-9622; http://www.usg.com), and Strait Flex (Con-Form International; 888/747-0220; http://www.straitflex.com), to name a few. They all share the common advantage of being held in place by embedment in joint compound, so there are no nail pops when the wood framing shrinks. Adhesion to the drywall with a continuous layer of joint compound makes a very stable corner that is resistant to edge cracking and the stresses of normal building movement. There are also vinyl corner beads that attach with spray-on contact cement, such as those from Trim-Tex (800-874-2333; http://www.trim-tex.com), Vinyl Corp. (305/477-6464; http://www.unimast.com), and Plastic Components (800/327-7077; http://www.plasticcomponents.com), that work very well. I like Trim-Tex because it comes in several lengths and widths, with plenty of angle and corner accessories. It goes on easily, and holds up well. Even if it gets hit, it's easy to repair, because the only damage is a little loose joint compound. However, if you insist on using metal corner beads, here are a few tips:

• For ceiling-to-floor corner beads, cut the bead approximately 1 1/2 inches short and push it tight against the ceiling. This reduces the risk of the bead binding and coming loose if the wall settles slightly. Follow this rule for any type of corner bead.
• Attach corners by working from the top down, installing fasteners opposite one another every 8 to 10 inches.
• Avoid nailing into the top wall plates.
• Make sure that the edge of the corner bead lies flat and tight against the wall and that the outside bead is raised only slightly above the plane of the drywall.
• Strengthen the edges with paper tape and joint compound to create a tape-on bead effect.

Expansion Joints

One detail that I don't see very often in residential work, at least in my part of the country, is the expansion joint, sometimes called a control or relief joint. An expansion joint is a metal or plastic strip that is attached between the abutting edges of two drywall panels (Figure 6).

Figure 6. Expansion joints can prevent ridging at tall expanses of drywall, as in stairwells. The joint can be painted to blend in or be concealed by trim.

You can walk into almost any two-story home and find at least a slight ridging along a horizontal seam on each side of the stairway. Often, there is excessive ridging that is impossible to conceal by feathering out with additional compound. An expansion joint solves this problem. The finished joint will be a maximum 1/2-inch-wide groove, running level around the stairway walls, located where the ceiling joist meets the first floor wall. If a metal or vinyl expansion strip is used, the joint can be painted to match the wall. If a trim board is used to conceal the joint, you can eliminate the strip and just leave a 1/4-inch gap just above the top of the first-floor wall plate. Either approach is much more attractive than a ridged seam.

Painting Tips

Do not allow painters to begin work before all taped joints are thoroughly dry; painting over wet joints is a major cause of joint discoloration. Differences in suction between the paper facing and the joint compound may cause the paint color to appear lighter or darker, making the joint conspicuous. A coat of primer is necessary to help equalize the porosity and texture of the taped drywall surface. I like to use USG's First Coat, a good-quality latex primer that's formulated with a high solids content, and apply it undiluted. However, even a good prime coat may not be enough when decorating with glossy paint. In this situation, I recommend applying a skim-coat of compound to the entire wall surface first to equalize the surface reaction.