Do it Yourself Drywall Finishing for Seams

This page contains taping and finishing instructions for flat drywall seams. Go to Installing Drywall Corner Bead and Finishing Inside Corners for help with those projects.

Drywall sheets are compressed on two finished edges so when two sheets are placed edge to edge, a small depression is formed. The seam between the sheets is taped with drywall tape and the depression is filled with drywall joint compound or mud, to create a smooth finished surface.

Flat drywall seams can be finished with paper tape or self–sticking, fiberglass mesh tape. Always use ready–mixed joint compound for finishing drywall seams. Setting–type joint compound will harden too quickly, causing problems. See Wall Finishing Tools and Materials for more information about drywall finishing tools, tapes and joint compounds.

Finishing Drywall Seams

Cut a piece of paper drywall tape the length of each joint to be finished. If you're using fiberglass mesh, tape all the flat joints you will be finishing at the same time. For inside drywall corners go to Finishing Inside Drywall Corners for taping instructions.

Scoop mud into a mud pan and collect a portion onto the rim. From the rim, work the mud onto the wall a little at a time. See Skim Coating Techniques for more on handling joint compound.

When using paper tape, apply a thick coat of mud over the joint and lightly press the tape into it. If you are using fiberglass mesh, apply a thick coat of mud over the tape using crossing strokes. Cover the tape and fill the depression to overflowing with excess mud. Work on about 6 feet of the seam at a time. Skim the excess mud from the mesh tape using the techniques in this crack repair process.

Hold a 6 inch joint knife at about a 30° angle. Start a few inches from one end of the tape and draw the knife down, pressing hard against the paper taped. Use enough pressure to squeeze all but a thin coat of mud from between the wall and the tape. Return the excess mud to the rim of the pan as it collects on the knife blade.

To avoid lifting the end of the tape, skim the end in the opposite direction and then continue down the length of the seam. When all the joints have been skimmed return the unused mud to the joint compound bucket and wait at least an hour before applying another coat.

Apply a second coat of mud to the seams when the first has set firmly. Fill the pan with mud and apply a thick coat over the joints. Use crossing strokes to cover the tape and fill the depression between the drywall sheets with excess mud.

Skim the excess mud from the seam using a 10 inch joint knife. Rest the knife on the high point along each side of the depression and "float" the blade over the center of the seam. Try to leave a thick coat of mud in the depression to level it with the surrounding wall. Don't press too hard on the center of the 10 inch blade. This will cause it to bow and create a perceptible dip in the finished seam.

Be sure to skim off all excess mud along the edges of the joint as well as the center. Allow the mud to dry for a couple of hours and repeat this step as many times as needed to completely cover the tape and fill the depression. Check for a good finish by holding the joint knife perpendicular to the wall surface and look for any gap indicating the depression is not quite level. Let the final coat of mud dry for 6 to 12 hours and lightly sand with medium grit sandpaper to finish the job.