How To Tape and Finish Dry Wall
Once your wallboards are hung, there are three separate parts to getting wallboard (also referred to as gypsum wallboard and drywall) ready for primer and paint. They are:
1. finishing nail or screw indentations
2. finishing corners
3. finishing joints
Fortunately, all three parts can be worked at the same time.
The nature of joint compound, hereafter referred to as mud, is that it shrinks as it dries. As it shrinks, it is normal for it to crack. Mud generally requires three separate coats to compensate for this cracking and shrinkage. Each subsequent coat of mud should be spread with a wider knife than the previous coat. Each coat requires 24 hours drying time between applications. Depending on your skill level, you may need to do some light sanding between applications. The final coat will always require sanding. You can use a finishing sander to speed up the job.
When sanding, it's best to start at the outer edges of the dried mud and work your way toward the center. Use circular motions applying just enough pressure to remove the imperfections.
Suggested Tools & Materials
3" drywall taping knife
6" drywall taping knife
10" drywall taping knife
Finish sander
Outside corner beads
Joint tape
Joint compound
Fine or medium grit sand paper
Old sheets, plastic or painter's canvas
Finishing Nail or Screw Indentations
Use a 3" drywall knife to spread mud into the indentations left by nails or screws. Scrap away excess mud. Repeat until indentations are relatively flush and then sand.
Finishing Corners
There are two types of corners: inside corners and outside corners.
Finishing Outside Corners
Metal beads are available and recommended for outside corners. Finish the outside corners by positioning the bead. Drive drywall nails or screws into the smaller holes about every five inches. Each nail or screw should attach to a wall stud that is located behind the wallboard. Using a 3" knife, spread about 1/8" of mud over the entire bead, one side at a time. Be sure to feather out the mud about 2 inches on both sides of the bead. Allow to dry. Sand lightly if needed. Repeat the process using 6 inch knife feathering out the mud and additional 2 inches on both sides. Allow to dry. Repeat the process for the final time feathering the mud an additional 2 inches using your 10 inch knife. Sand away the minor imperfections.
Finishing Inside Corners
A similar procedure is used for insides corners. You may elect to use paper inside corner beads or to embed paper joint tape into the corner. To embed joint tape spread about an eighth inch of mud into the corner. Make sure the mud is spread wider than the tape. Fold the tape along the crease and position into the corner. Starting at the top, use a 3" knife to embed the tape and squeeze out the excess mud by placing the blade flush against the tape and pulling down while applying pressure. Do one side at a time but work quickly as the mud will began to surface dry if you take too long. Apply a second 1/8th inch coat of mud over the tape. Allow to dry. Add subsequent coats feathering out the mud an additional two inches or so. Finally, sand out any imperfections with medium or fine grit sand paper.
Finishing Joints
To finish tapered joints (joints where two pieces of drywall meet and where the edges are tapered), spread mud into the joint using a 3" or 4" knife. Allow 24 hours to dry. Repeat the process using a 6" knife. Allow to dry. Use a 10" knife for the final application. Allow 24 hours to dry. Sand away any imperfections.
Sometimes you may have joints joined where they are not tapered - often called butt joints. In this case you may have to feather the mud out as much as 2 feet on each side of the joint to give the wall the illusion of being perfectly flat.
Tip: Finishing drywall is more of an art than a science. Production speed comes with experience. Professional finishers make the job look easy because they have acquired years of experience perfecting their technique. Work patiently and don't worry too much about mistakes. They are relatively easy to correct. However, don't prime and paint until you've corrected your mistakes.
Controlling Dust
Dust control is an important part of finishing drywall. Unless you're working in a newly constructed area, you'll want to prepare for the dust caused by sanding. Always wear a dust mask and goggles to protect your eyes and lungs from the non toxic dust. Open windows and consider using a box fan to exhaust the dust. Drape sheets or a canvas over large items and remove small items from the work area.
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