How to Cover Joints in Wallboard

Place self-adhesive drywall tape evenly over all joints from the top to the bottom. Ensure that the tape is not wrinkled and that an even amount lays flat on either side of the joint.

Apply joint compound over the taped joints using a 6-inch drywall knife. Place joint compound in a drywall pan. Scoop joint compound onto the knife and scrape it on the side of the pan, leaving a bead an inch wide on the end of the knife. Apply the joint compound to the joints using an upward motion at a low angle to the wall. Remove excess joint compound by pulling the knife downward at a larger angle to the wall. Allow the joint compound to dry for 24 hours.

Sand the joints using a pole sander with a drywall sanding screen installed. Lightly guide the pole sander over the center of the joint and then along the edges to remove ridges and to blend the joints into the rest of the wall.

Repeat the joint compound application process using a 10-inch drywall knife on all the joints. This will help blend the joints into the rest of the wall. Allow the second application to dry for 24 hours and sand with a pole sander. Use a drywall sanding sponge for more detailed sanding in areas that need it.