Use a 4-inch knife to apply a heavy coat of joint compound over the sheetrock at the
inside corner (see Figure 2-32). Measure and cut the tape to the length required for
the joint. Fold the tape in half lengthwise, keeping both edges even. Use a corner
tape creaser if necessary. Apply the tape at the top and work downward, running the
edge of your hand at the center of the tape to ensure that it is in the corner. Using
the inside corner tool, press the tape into the compound, working off all excess
compound and being careful not to wrinkle the tape or leave air bubbles.
Figure 2-32. Applying tape at corners
Apply the first coat of joint compound over the tape then apply a medium coat of
joint compound. Feather the compound with the 6-inch knife to about 2 to 3 inches
on each side of the joint. A good job of feathering and smoothing will minimize
Apply the second coat of joint compound over the tape and nail coverings. The joint
compound previously applied must be completely dry. Use the 4-inch knife to apply a
thin coat of compound over the nails, removing any excess compound. Using the
steps above, apply the second coating to the joints using the 6-inch knife and
feathering out 6 to 8 inches on each side of the joint.
Apply the third coat of joint compound (see Figure 2-33, page 2-24). The joint
compound previously applied must be completely dry. Using the step above, apply
the third coat using the 10-inch knife and feathering out 10 to 12 inches on each side
of the joint. Nails should not require a third coat, but it may be applied if necessary.