TAPING
DETAILS:
Drywall joints are taped with a paper material and joint compound
that you can buy already mixed or in powder form that you mix yourself
with water. The outside corners are finished with a metal bead,
instead of paper tape; inside corners are paper-taped. The metal
edging is used to protect the corners from hard knocks which would
damage the edges.
Sealing
joints and filling holes-
It will require two spot coats of joint compound to cover the dimples
where the board has been nailed. Let the first coat dry before applying
the second coat. Apply compound to fill the channel formed by the
tapered edge of the board at the joint. Place the joint tape on
the compound while the compound is still wet. Embed tape in the
compound with a knife. Then apply a 6- to 8-inch wide coat of joint
compound over the tape. Lightly sand the first coat when dry. When
this is dry, a final coat, 12- to 14-inches wide, should be applied.
Let
the final coat set about 24 hours or even longer if there's lots
of humidity in the air. Then with a damp flat sponge, smooth the
compound. You may have to lightly sand the area to smooth the joints
completely after the joint compound has thoroughly hardened. Easy
does it. You should use a sanding block so you don't dig the compound.
If you do have problems, go back over the area with a thin coat
of joint compound. Smooth it with a taping knife, then use the damp
sponge again, as detailed above.
If
you look closely, you will see that the edges of drywall are slightly
tapered. This taper accepts the thickness of the tape and the joint
compound so the buildup of these two materials match the surface
of the drywall panel.
Installing
outside corner bead-
The bead strip or molding should be nailed through the drywall and
into the framing underneath. Use a drywall knife to apply a 6-inch-wide
coat of joint compound on each side of the bead. After the first
coat is dry, apply a second coat over the first about 9 inches wide.
Feather the edges of the joint compound so the edges "taper" away
from the metal bead left showing at the corner.
When
the compound has hardened, go over the surface of the compound with
medium grit abrasive (sandpaper). Use a sanding block; you don't
want to dig into the compound, which is soft, and leave marks that
can't be covered with paint. If the wall will be papered, the marks
are not as critical; you should, however, make the job as smooth
as possible-paint or paper.
Taping
inside corner-
Carefully crease regular drywall tape lengthwise down its center.
The trick is to get the edges matching and then, on a flat surface,
run a taping knife along the tape to crease it. After you practice
this a couple of times, the job will become easy to do. Apply a
coat of joint compound to both sides of the joint. You want the
compound fairly thin- just about the thickness of the tape that
will be embedded in it. While the compound is wet, press the joint
tape into the compound with your fingers, getting it evenly into
the corner. Then, with the taping knife (use at least a 6-inch wide
knife) press the joint tape into the joint compound, being careful
not to dig into the tape where it bridges the corner joint. Feather
the edges of the compound from the tape out onto the panel. Let
the compound dry. Then apply another coat of compound about 6 inches
wide over the tape on one side of the corner. Let the compound dry.
Then repeat the treatment on the other side. When the compound is
hard, sand the joint area lightly with medium grit abrasive. Do
not over-sand or you'll dig into the tape.
MENDING
SPLIT TAPE:
Very carefully cut and open the split tape with a razor knife. What
you want to do is give yourself enough working room so you can force
glue behind the tape.
When
the split is opened, squirt glue in back of the tape. Press the
tape down with your fingers. If the tape wrinkles at this point,
cut it just slightly with the razor knife. The cut should let you
position the tape flat against the wall surface.
Clamp
the tape in position with straight pins. Push the pins through the
tape and into the wall surface. Let the glue dry for a couple of
days, and then remove the straight pins.
Complete
the project by touching up the area with paint, which will fill
the pin holes and the razor cuts in the tape. You may have to repaint
the entire wall to blend the repair in with the wall surface.
