Step 8. When the tapered
joints are thy, use a 10-in, knife to apply the first topcoat of
compound. Apply the compound so itís as smooth as possible. Then remove
the excess in a couple of smooth strokes.
Step 10. Apply compound for
the second and final topcoat. Your goal is to spread a 12-in.-wide coat
over the joint. Smooth the middle first, then smooth each edge. Clean
the knife on the edge of the pan after each pass.
Step 9. After the first
topcoat is dry, lightly sand it to remove any ridges. Use a sanding
block or a pole sander to cover more area faster. Donít worry about
filling any gaps, the next coat of compound will take care of them.
Step 11. When dry, sand all
the joints using 120-grit paper. Use either a wide pole sander or a
small sanding block. For best results, go over the joints one more time
with 100-grit paper wrapped around a sanding block.
|The main ways to prevent
joint cracks that disrupt taped seams is to use stable studs that wonít
twist or warp. That means bypassing (or returning) unusually heavy studs
that are overloaded with moisture. As the wood dries out, which may rot
happen until the first heating season, wet lumber can shrink and twist
enough to pop nails and break open joints.
You also need to set framing carefully so that drywall panels will lie
flat. Even small misalignments between standard studs or the extra
framing installed around window and door openings can create ridges in
the edges of drywall panels that rest on them. You could cover these
errors with extra joint com pound. But that can lead to cracking as
thick coats dry unevenly. The best bet is to align all studs, if need
be, by driving a few extra nails to shift the studs slightly one way or
another before installing drywall.
Standard Ĺ-inch-thick panels can bridge the spaces between studs. But
they need full support along the panel edges. Typical framing provides
continuous sup port along the floor and ceiling, but not always at
corners. Several types of drywall clips are designed to reduce wood use
and construction time by holding unsupported drywall edges together.
Sometimes they work. But sometimes they donít and the corner shifts,
cracking the tape and joint compound. So itís best to provide solid-wood
sup port on all drywall edges. The time to do this, of course, if when
the framing is exposed.