Taping Drywall Seams Properly
Using mesh tape hides joints more entirely than paper tape, cover the perpendicular or butt joints first, pressing it firmly into place using a drywall knife. Then cover the horizontal seams, and finally cover the corners. Do not overlap the tape. Cut it where the parallel line meets the perpendicular and start again on the opposite side of the line.
Joint Compound: First Coat
The first coat doesn’t need to be flawless, just keep any excess to a minimum. To do this you will be smoothing joint compound across the drywall panel following the same perpendicular, horizontal, corner pattern by applying pre-mixed joint compound on top of the mesh tape with a drywall knife. Smooth the edges to manage excess compound.
Feathering is an application procedure that adds pressure and angles the utility knife as it moves towards the edge of the compound. This makes the thinnest layer of compound at the outlying edges of the seams.
On the inside corners, apply joint compound to each side and crease paper tape along the centerline. Gently push it into place with your fingers. Do no cut the tape, run your knife carefully down one side and then the other to create a firm fit.
Outside corners
On the outside corners, apply a layer of compound to either side. Nip the paper beading to the appropriate height of the wall and press it into place with your fingers. Slide a drywall knife along the beading to make sure the fit is snug and simultaneously remove excess compound. Beading is available in various mediums, which include metal, paper and vinyl.
Covering nails and screws
Finally, using a drywall knife, coat the fasteners with a layer of compound.
Allow the first coat dry 24 hours before starting the second coat, which is sometimes called the fill coat.
A 6-inch drywall knife is used to screen the first coat of tape and joint compound about 3/16 inch thick on the vertical seams, use a 10-inch knife feathering joint compound wide so that it blends with the drywall and then lightly run the knife over the middle. When you’re finished with the second application, the mud should be between 10 to 12 inches wide.
Inside and outside corners
For inside corners, use a 6-inch drywall knife to smooth the mud along one side only. You’ll do the other side on the third coat.
Apply joint compound on both sides of outside corner, use a 10-inch knife to apply compound to both sides. Smooth the second layer out past the first layer in order to merge the edges with the wall.
Apply a second coat of compound over all fasteners and allow to dry 24 hours.
Third Coat
The third coat is called the finish coat, which means you should leave no tool marks.
Using a hand sander, sand the drywall seams lightly with 120-grit sandpaper.
Wear safety goggles and a face mask to prevent dust inhalation. Windows should be open and doorways covered with plastic to reduce the mess in other parts of the house. You can also use a vacuum sander or wet sponge to reduce the amount of dust produced.
Apply joint compound to the seams and feather the edges again for a smooth finish with no marks.
Apply compound to the other side of the inside corner with a third coat of compound cover nail and screw heads that secure the drywall panel to the studs.
Cover the fasteners again, if needed. Allow the finish coat dry for 24 hours and lightly rub with sandpaper for a smooth finish.
Skim Coat
For a pro finish, apply a graze coat which is a thin layer of joint compound that covers any rough areas left after the final coat of compound.
Mix the skim coat according to the manufacturer’s instructions in a bucket with a wire whisk. Then apply skim coat with a paint roller in small sections, work in 4-foot sections to roll on a finish compound. Immediately remove the excess with a 12-inch drywall knife. Let the skim coat dry for 24 hours, then lightly sand for a smooth finish.