Page 285 - 2018 National Home Improvement

2018 National Home Improvement Estimator, All Rights Reserved Page 231

2. Press the paper tape into the mud with a drywall knife, not your hand. Then smooth the surface with
the knife. Press hard enough to force joint compound through the small perforations in the tape, if the
tape has perforations. But don't press too hard. Some mud should remain under the tape. When you’re
done taping and embedding the tape, let everything dry overnight before beginning the finish coats.
3. Cover the tape with cement, feathering the outer edges at least 2” on each side of the paper tape.
Feather an additional 2” when covering a cut joint, as there’s no taper. Then let the cement dry
overnight.
4. When dry, sand lightly. A pole sander speeds this work. Then apply a thin second finish coat,
feathering the edges a little past the edge of the prior coat. Use drywall topping compound designed for
finish coats to create a smooth joint that’s easy to sand. You can buy “all-purpose” compound, which
can be used both for bedding and topping. But it’s better to use bedding compound for bedding, and
topping compound for finishing. Use a wider drywall knife for this finish coat, up to 12” wide. To save
sanding time, keep this finish coat as smooth as possible. For top quality work, apply a third coat of
mud after the second coat has dried and been sanded.
5. When the last coat of cement is dry, sand smooth.
6. Fill all nail and screw dimples with at least one coat of joint compound. Sand the surface after each
coat is dry.

Use folded perforated tape on interior corners. See Figure 10-06. Fold tape down the center to form a
right angle. Tape designed for this purpose already has a crease down the middle. Then apply cement
on each side of the corner and press tape in place with the putty knife. Use a drywall corner knife to
embed the tape on both intersecting walls at the same time. Finish the corner with a coat of joint
compound. Smooth the cement on both surfaces of a corner at the same time with a corner knife. Let
the corner dry overnight and then sand the surface smooth.

For exterior corners, use metal or plastic drywall corner bead. This makes a more durable corner, able
to withstand impacts that are likely at external corners. Also apply paper drywall tape over the edge of
the metal bead. Nail or screw outside corners to the board every 8” and finish with joint compound.
When you’re finished applying tape, bead and mud at both internal and external corners, you should
have a 4” strip of mud on each side of every corner. Don’t worry if this strip isn’t smooth. Sanding and
more finishing will follow.

Drywall mud shrinks as it dries. So apply a little more than actually needed to make a smooth finish,
especially over fastener heads. Bear in mind that drywall sanding is very messy! It creates huge,
choking clouds of dust. Wear a dust mask to avoid inhaling this stuff. In an unoccupied house, the
mess isn’t as much of a problem. However, if you're working in an occupied home, you'll need to control
the dust. Homeowners don't appreciate having everything in their home covered with a thick layer of
white powder. You'll either need to seal off your work area with plastic sheeting, or use a dustless
sanding system, such as a wet sanding sponge.