Taping and mudding is the process that joins pieces of drywall into a single solid wall. Fiberglass mesh tape and coats of all purpose drywall mud are applied to reinforce joints and conceal screws and nails. Fiberglass mesh tape is easier to use than paper tape. Compound has to be used to secure paper tape, and there is the problem of it wrinkling or buckling. Fiberglass mesh tape is usually self adhesive and this feature avoids these challenges. Fiberglass tape makes a stronger joint that is less likely to develop defects than one finished with paper tape. It is also mold resistant. When taping and mudding are done correctly, the wall is flat and smooth and the seams underneath are hard to see.
- Unroll enough fiberglass mesh tape to cover a flat seam you’re finishing and cut it from the roll with a utility knife. Starting at one end of the seam, press the tape against the drywall so it covers the joint and lays flat against the wall.
- Mix an amount of drywall mud that you’ll be able to use in 20 minutes to an hour, depending on the time it takes for the mud to set. Be sure to check the specifications on the container. Once the becomes hard you can no longer apply it.
- Hold one end of the fiberglass mesh tape against the wall with one hand while you spread mud over it with a 4- to 6-inch drywall knife, moving the knife along the tape away from your hand. If you don’t hold the tape, the knife can move it, and it is difficult to reposition the tape once it has a layer of mud on it. Continue spreading mud along the length of the fiberglass mesh tape, releasing the end when you have covered about a foot of the seam. Scrape the mud flat when the seam is covered, being careful not to catch the corner of the blade on the mesh and pull the fiberglass mesh tape away from the wall.
- Let the mud dry overnight, then sand it flat with 120-grit sandpaper. When the seam is flat, apply the second coat of mud with a 10 inch utility knife then scrape it flat, and then letting it dry overnight.
- Sand the seams again with the same sandpaper. Apply the third and last coat of mud with a 12 inch utility knife this time. By using a wider knife each time this allows the seam to blend in the wall. Let the mud dry overnight again.
- Sand the wall again for the last time.
The steps are similar for doing inside corners. Fold the fiberglass mesh tape in half lengthwise, starting at one end of the seam, press one half to the wall on one side of the corner. Unfold the tape in 4-foot increments and press the other half to the other wall. Continue until you reach the other end of the seam. Coat with mud, then finish with regular joint compound.
