DIY Finishing Drywall Seams with Fiberglass Mesh Tape

• Drywall Finishing Materials and Techniques
• Finishing Seams with Paper Tape
• Installing Drywall Corner Bead
• Finishing Inside Drywall Corners

These instruction cover finishing drywall seams with fiberglass mesh tape and ready–mixed joint compound. To finish drywall seams with paper tape use these instructions. To install drywall corner bead use this link, finish inside drywall corners here and use this link for more about drywall finishing materials and techniques.

Choose the Joint Compound

You can use ready–mixed joint compound for this job or if you can work quickly, setting–type may also be a good choice. The main difference between the two is the time it takes to finish a seam. Ready–mixed can take as much as a day to dry before a second coat can be applied, while setting–type will set, depending on the grade used, anywhere from 10 minutes to an hour.

Tape the Joints

When using fiberglass mesh tape for this job it's best to finish all the flat seams before going on to finish the inside corners at ceilings and adjacent walls, otherwise it can be difficult to blend the two different types of seams together.

Start at a corner and unroll the tape over the seam without pulling too hard on the roll so as not to stretch it. At the other end, cut the tape off squarely by holding a joint knife as shown, firmly against the tape while pulling back quickly on the tape to tear it.

Use One Piece of Tape

Wherever possible tape the full length of the joint between two drywall sheets without cutting the mesh tape. This will limit the chance of pulling the ends up with the joint knife when skimming the mud out.

Coat the Joint

Use crossing strokes with a 6 inch joint knife to apply about ½ inch of mud over the tape and depression between the drywall sheets, from one ceiling to floor. On ceilings, work on a manageable

Skim the Joint

Immediately skim the excess mud from the joint holding the knife at about 30°. Rest the blade evenly on each sheets of drywall so it rides along the edges of the depression. Leave a coat of mud that covers the tape and fills the depression. Skim along the edges to remove any buildup of mud there. Let the mud dry for a few hours or more before applying a second coat.

Second Coat the Joint

When the first coat is completely dry, sand any raised, tape fibers using 120 sand paper to go over it lightly with a couple of strokes and wipe or vacuum the dust off the wall. Apply a second coat of mud to the joint using a larger joint knife in crossing strokes to cover the joint and the outer edges of the first coat with about a quarter inch of mud.

Skim the Second Coat

Immediately skim the mud from the joint resting the blade on the high point along each side of the depression to "float" the blade over the center of the joint, leveling it with the surrounding wall. Don't press too hard on the center of the blade, this will cause it to bow and create a perceptible dip in the finished seam. Clean the blade off on the pan frequently to avoid a buildup and go over the edges of the mud to skim off any buildup there.

Check for a Level Joint

When the mud has dried, check for a level joint by holding the knife perpendicular to the wall surface while looking for any gap between the blade and the wall, indicating the depression is not quite level. Apply a third or fourth coat of mud if necessary to smooth the joint. Let the final coat dry for 6 to 12 hours and lightly sand with medium grit sandpaper to finish the job.