You have to get creative in patching drywall at times. While I can't cover every possible situation here, hopefully I can give you enough ideas to start from. I recommend using drywall compound instead of spackle since spackle varies from brand to brand and can be unreliable. You can get compound in containers as small as one quart at some stores and it is cheap and easy to work with. It remains water soluble so you can wipe it off with a wet sponge anytime, until you paint it.
Holes
Small nail holes. Apply compound with
a putty knife and force it into the hole. Then smooth off the compound
into the surrounding texture with a finger so it blends in. Wipe off
any excess with a damp sponge. Usually that is all you have to do, and if the
paint color is a white, the compound will probably not show.
Broomhandle size hole. You will need some
support for the patch. You might get by with mesh
tape over the hole and compound forced through it. But this will be
fragile; don't do this for a doorknob hole; use the method below for a
towel bar, or put a large flat door bumper over the hole.
Towel bar hole, where one has pulled
out of the wall. It would be best to fasten a
slender block of wood behind the hole so you can screw into it. You may
need to enlarge the hole slightly so you can set a block of wood about 1x2x6"
into the hole. Use a screw in the center of it as a handle as you work it in
place, and then fasten it in place top and bottom with a couple drywall screws.
For this you can drive the screws by hand or with a drill driver.
Fill the hole with compound or Fix-It-All with compound over (see below).
Larger hole. Cut a piece of scrap drywall
and hold it in place with one or two splints. If the piece of drywall
that was cut out was saved, that will work very well. BTW you can get patch
size drywall at some home centers. For a splint, use a scrap of wood about
1x1 or 1x2 behind the hole and fasten it in place with a drywall screw on
each end. To hold it while doing this, set a screw near the middle to use as a
handle. Then remove the handle screw and set the patch in place and
screw it to the splints. These splints need not be fancy since you will never see
them again, but it is best if they are at least reasonably flat on the face side.
Metal ring around the hole, like for an
old electrcial box. The metal may interfere
with your patching. I usually use a block of wood and a heavy hammer to bang
the metal back enough so it does not protrude and then proceed with the patch.
It is usually messy to totally remove the metal ring or box, and it is not
necessary.
Deep cracks around your patch. The compound
may shrink and split or crack. Instead, use a fast dry patching compound
like Fix-It-All or Quik-Fix. It adheres well and dries fast, but it doesn't sand smooth,
so leave a little recess over it to fill with compound. Fix-It-All will dry
hard enough to work with in 15 to 30 minutes, and then apply compound over it.
The compound will probably discolor tan over the Fix-It-All but this can
be covered by a stain blocking primer.
You can also use one of the
fast set compounds; they come in powder form for mixing with water, but my experience
with them is that they do not dry as fast as claimed. They supposedly dry fast
enough to work around in the stated time (20, 40, or 60 minutes) but my experience
is that they remain damp for some time, maybe even a day, so you will have to wait
to sand and paint them. And they come in large bags or boxes, but you can get
Fix-It-All in a small box. The fast dry compounds are good for patching plaster or
blending drywall to plaster since they are setting compounds, like plaster, and do
not shrink. The other advantage is that you can do the patching in one step.
Tip: when you splice in a piece of drywall,
you will need to tape around it or the compound will split. But the
tape will make an unsightly hump. Cut around the patch a little over
one inch back from the joint on each side; use a utility knife and cut
the paper face. Then lift off the top layer of this paper face to create a recess for
the tape; you can use the knife, or a 4" wallpaper razor scraper works
well. Sand the recess to smooth it some and remove any loose paper; then set
mesh tape in this recess and fill with compound. The mesh tape may not want
to adhere well to sanded drywall, so wipe it off with a dry rag or paper towel.
The compound will hold it in place ok. You should be able to get a pretty flat
patch with this method.
Surface Problems
When removing paneling, tile, glued-on
mirrors, and sometimes wallpaper, you may be left with the drywall surface
torn up some. The fix is to sand it lightly to remove the fuzz and wipe it
with a damp sponge. If there is any surface paper peeling off, remove that.
Then skim coat with compound and sand it smooth. You may have to repeat this
process a second time. The best tool for skim coating is a drywall trowel,
but a drywall knife will also work; a drywall trowel has rounded corners.
If you still have too much raggedness, try priming it with a latex primer
(see below). But realize that texturing will cover a lot of minor ills.
If there was water damage and the surface
paper has fallen off, and the drywall is soft and powdery, it is best to cut
away that section of drywall and replace it. However, for a temporary fix,
you can try the skim coating fix above. Painting the soggy part of the drywall first
with white glue or latex additive may help firm it. If the water damaged area is
only discolored, just prime with a stain covering primer and paint. I usually use
Zinsser's Cover Stain (oil) but their B-I-N (shellac) will also work.
Loose Tape or Corner Bead
If you have drywall tape coming loose, you
will have to replace it. You can recognize this since it will be in a straight
line, and the tape is about 2" wide; expect the tape to be horizontally about
4' up the wall and in the corners. Be sure of what you are seeing here before
starting. If the tape has split, with a ragged tear, there may be a structural
problem. In that case, remove the tape and nail or screw the drywall to the
framing in that area. To remove the tape, cut on both sides of it with a utility
knife and pry it up, using a wet sponge to assist, if necessary; realize that
there will probably be a thick layer of compound over the tape. On the other hand,
if the tape has lifted off on one or both sides of the joint, that is most likely
caused by it being applied improperly. Don't be too critical of the installer;
this happens to the best of them at times, and it is why I have switched to the mesh tape.
In this case, remove the tape and apply new mesh tape.
If you have cracking along the edge of corner
bead on an outside corner, this may well be because it was not nailed enough or that
it was crimped in place instead of nailed.
You can cut away some of the compound (it may chip off
easily) and nail the edge of the corner bead firmly to the framing; be sure to
set the nails slightly below the surface and use all the nails you have to. I
don't recommend trying to replace the corner bead; that would be a hassle for
the inexperienced. However, if you have rusted corner bead, you may have no
choice but to remove it and start over.
If you have a ceiling-to-wall joint separating
on an inside wall, you may have a problem with "truss lift"; see that heading in
the drywall topic. There is no good solution to this except to install crown
molding attached to the ceiling, not the wall.
Texturing and Finishing
To texture your patch, wait for the
patch to dry. You can use aerosol spray can texture; there are several types, even
one for popcorn ceilings. The nozzle of the water based Homax brand
works best for me. There is also a fast dry (oil) version but it is a terrible
mess to clean up and I don't recommend using it. Spray on the texture and if
it doesn't come out right, scrape it off right away and try again. In some
cases, you can get enough texture to solve the problem by applying soupy
compound with a sponge. When the texture is dry, you can wipe off the excess with a
wet sponge. The patch must be primed and painted; if you don't prime, it will
be difficult to obscure it. Use a latex primer like Zinsser's Bulls Eye 1-2-3.