Step 23d – Install Corner Beads and Second Coat
All of the edges of the drywall sheets are now covered with tape except for two. The edges of the drywall that butt up against the floor, and the edges of the sheets that come together to form an outside corner. The edges against the floor will eventually be covered by trim, and the edges that form outside corners are covered with what is called corner bead. The type of corner bead I am using is called mini-bullnose. It has a rounded edge, as opposed to the more common squared off edge found in most houses. The rounded edge of the mini bullnose is less likely to chip when impacted and gives a softer feel to the style of the home.
Installing corner bead is very simple. You merely attach the corner bead to the drywall with crown staples and then apply joint compound. Using a six inch taping knife, you hold one edge on the corner bead and the other on the wall so the mud is forced into the space between them.
After stapling and mudding all of the corner bead, I started working on the second coat of mud. Every taped joint and corner bead receives a second coat. We currently have a little bump where each piece of tape lies and this coat will smooth that bump out. As with the taping, I started with the corners. Best practices call for mudding one side of each corner with a six inch taping knife, waiting for it to dry, and then getting the other side of each corner. Unlike a drywall contractor, I have the luxury of time on my side. I can work on mudding drywall for half of the day and do something else on the other half. This allowed me to space the corners out so there were dry when I came in to do the other sides.
For the flats, a larger 12 inch taping knife is used so that the entire space between the two tapered edges of the drywall is completely filled with mud. For the butt joints, the twelve inch taping knife is also used so the bump where the tape lies becomes a little more gradual. The idea is to run one edge of the knife along the tape and one edge along the wall so the space between them is filled with mud. Once this is dry, we can extend the bump further and make it even more gradual by running one edge of the knife around the middle of the bump and the other edge along the wall.
Corner beads also receive a second coat of joint compound to fill in any areas where the first coat shrank a little. Finally, everything is given a quick sanding.