Let’s face it—no wall is perfect.
And if you want to rejuvenate a room with
fresh paint, it’ll look a whole lot better if
you repair and smooth out those beat-up
walls first. Some flaws, such as shoddy
taping work, have been around since day
one. Others, like cracks and nail pops,
start showing up months or years later as
the house ages. And still others are just
insults from day-to-day living: holes from
doorknobs, dents from furniture, holes
from shelving and picture hangers. The
good news is that you can fix all these
problems. You only need a few inexpensive
tools and a bit of finesse. With our
tips, some patience and a keen eye, even
beginners can get good results.
In this story, we’ll show you how to
repair and cover the most common drywall
flaws so that they’ll be all but invisible
after that new coat of paint. The fixes are
ordered from the most common and easiest
to ones that are less common but more
challenging.
To find the problems, inspect the entire
wall surface by holding a light close to the
wall and “raking” across the surface. The
light will highlight wall flaws that aren’t
obvious to the unaided eye (below).
Circle each problem area with a pencil
(not a pen or marker, which may bleed
through paint later) to mark it for repair.
1. Fill nail pops and small holes |
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Small holes from brads or picture hangers are simple to fix. Gently tap on the wall with the handle of your putty knife to drive any standing drywall facing paper below the surface and create a tiny crater, and then fill it with wall filler.
Nail pops are usually caused by fasteners that are driven through the drywall paper during installation, or by a gap between the drywall and the stud. Then vibration and seasonal wood swelling and shrinkage cause the overlying
filler to pop out from the wall. Drive in another 1-1/4-in. drywall screw near
the nail pop so the head penetrates just below but not through the drywall
paper. Then remove the old screw by pushing the screw gun tip through the
middle of the nail pop and backing out the screw. If it’s a drywall nail, drive it
into the stud with a nail set and leave it. Then dimple the old hole (Photo 1)
and fill it and the new screw head with two coats of filler (Photo 2). |
Click Image to enlarge.
Click Image to enlarge.
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2. Caulk cracks at inside corners |
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| Hairline cracks at inside corners usually signal slight
movement between adjoining walls. Choose any type of
latex caulk and cut the tip just short enough to leave a
1/8-in. hole in the end. Squeeze a narrow line of caulk
directly over the crack (Photo 1). Then mold the wet
caulk into the corner with a moistened finger (Photo
2). The caulk will remain flexible and keep the crack
from reappearing. Avoid thick layers of caulk, which
may look too rounded in a square corner. |
Click Image to enlarge.
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EDITOR’S NOTE |
Mud basics
Most of the fixes in this story require at least two
coats of taping compound. Compound is too thick
to use right out of the bucket, so mix in small
amounts of water until you get a smooth, mashed
potato–like consistency. Use a slightly runnier mix
for embedding paper tape. Let each coat dry completely
(usually overnight) before applying another
coat. If you have leftover ridges from tools, let them
dry and scrape them off with a putty knife before
adding the next coat. With the first coat, don’t
worry about craters, scratches or other small flaws.
Just try to avoid large humps and make sure any
patches are covered. The second coat is to fill in and
smooth out any voids or low spots.
Generally, larger patches call for wider coats of
drywall compound to mask them. That way, higher
areas from patches or existing humps can be feathered
out over wide areas so the wall will appear
flatter. The most common mistake is to use narrow
rather than wide swaths of compound over patches
and humps. Strive for a thickness of 1/8 in. or
so over the fix and feather the edges flush with the
drywall. Sand all the fixes with 120-grit drywall
sandpaper. Use a handheld sander for small jobs
and a pole sander for big jobs. Check your work
with the light again after sanding to look for areas
that need more work. You can always add a third
or even fourth coat of joint compound to fix any
remaining problems.
-Travis
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3. Patch medium-size holes |
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Large holes still require old-fashioned
fixes that include cutting out a square
chunk of drywall around the hole,
installing backing, adding a drywall patch
and then taping the wound. But holes
under 6 in. in diameter can be more easily
repaired with a self-adhesive drywall
patch. Find 4 x 4-in. or 8 x 8-in. squares at
home centers and specialty paint stores.
Select a size that’ll overlap the sides of the
hole by at least 1 in. Pick away any loose
chunks of paper or gypsum that protrude above the surface.
Then peel off the backing and stick the patch in place.
Spread a wide, thin layer of mud over the patch and
the surrounding wall. The thin metal patch is perforated
so the mud can penetrate and lock it in place.
After the first coat dries, spread a second layer of mud
to fill in imperfections and low spots, then sand. |
Click Image to enlarge.
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4. Nail, retape and mud cracked corners |
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If a metal corner bead is badly dented or damaged, your only
option is to pry it off and replace it. That’s a big job because
you’ll have to remove and reinstall the base trim as part of the
project. But if only the edges are popping through the surface
or there’s a hairline crack along the flange, you can fix it.
(Chances are the flange of the corner bead wasn’t nailed
securely or the taper neglected to tape the edges.)
Drive 1-1/4-in. drywall nails through any corner bead
edges that are loose, using as many nails as needed to hold
the flange flat to the wall (Photo 1). Center fiberglass mesh
tape over the flange over the entire length of the
corner bead (Photo 2). Spread two coats of joint
compound over the mesh tape, using the corner of
the bead as a guide for the taping knife. If you have
a corner that’s in a vulnerable spot and constantly
gets bumped, use “setting” compound for the first
coat and regular joint compound for the second
one. Setting compound is much tougher and won’t
crack nearly as easily. But be careful to apply even
coats that don’t project beyond the corner or leave
humps or tool marks. Setting compound is very
hard to sand. |
Click Image to enlarge.
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5. Cut out and replace loose tape |
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| If the tape is blistering or lifting away from
the wall, it’s because there wasn’t enough
joint compound under the tape to anchor
it to the drywall. The solution is to cut
through the paint and joint compound
and peel every bit of loose tape away from
the wall to expose the surface behind
(Photo 1). Be aggressive with this step,
even cutting and peeling tape beyond the
evident crack. There’s bound to be more
poorly anchored tape that just hasn’t come
loose yet.You can tell just by looking at the
lack of compound on the drywall surface
behind. After cutting loose material away,
fill the hole with setting compound
(Photo 2). When that hardens, embed a
strip of paper tape in taping compound a
few inches beyond and directly over the
patch. Then overlay two wide swaths of
taping compound to blend the patch into
the wall. |
Click Image to enlarge.
Click Image to enlarge.
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6. Taper humped joints |
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| Butt joints (where drywall joins at the ends) often have unsightly
humps left from built-up and/or poorly feathered edges when
the walls were originally taped. (These really show up with the
raking light.) Fix them by overlaying a wider layer of compound
to blend the hump in with the surrounding wall. Apply the first
layer of compound with a taping knife, working from the bottom
to the top of the hump (most of the time these will be vertical
joints; Photo 1). Use a little more pressure on the knife edges on
both sides of the hump to help feather (taper) the edges. Strive
for an overall width of at least 2 ft. for the patch. Immediately
after applying the first coat, drag a knockdown knife over the wet
compound, smoothing the edges flat against the drywall (Photo
2). (A knockdown knife, $15, has a 22-in.-long rubber blade.)
Wait too long with this step, even a few minutes, and the rubber
blade will drag in the mud and you’ll have poor results. Let the
first coat dry and apply a second, slightly wider and thinner coat
with the same techniques. Check out your patch with a raking
light while sanding, and add more coats if needed to fill in low
spots, craters or grooves. |
Click Image to enlarge.
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7. Carve out and fill joint cracks |
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Midwall cracks are tricky to fix and may crack
again, so there are no promises here. That’s
because the cracks usually occur at the corners of
windows, doors and other openings, which are the
weakest points in the framing. Seasonal movement
or foundation shifting shows up there, especially if
the drywall hanger put a joint at that spot. If so, the
only sure fix is to tear off the drywall and seam
new pieces near the center of the opening.
However, try this fix first. Carve a 1/2-in.-wide
by 1/2-in.-deep “V” with a utility knife in the center
of the crack (Photo 1). Fill the crack with setting
compound and let it harden (Photo 2). Then
embed paper tape in taping compound directly
over the patch (Photo 3) and overlay it with two
or more wide layers of taping compound. |
Click Image to enlarge.
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8. "Skim coat" large damaged areas |
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If there's significant damage over a large area of drywall, the
only answer is to “skim coat” the entire area. That means
covering the surface with a thin layer of joint compound to
bury the damage. Tackle one area at a time, preferably areas
no larger than 4 x 4 ft., at least until you get the hang of
applying and smoothing larger areas of compound.
Prepare the wall by picking away any loose edges of drywall
facing paper. Prime the leftover raw paper with any
type of priming paint to seal the raw paper. (Kilz is a great
product to use for this step because it seals well and dries
fast.) Dab at the wet paint with a foam brush or rag to saturate
the paper and wipe away any runs. Let the paint dry
and lightly sand away any standing paper nubs. If you sand
through the paint and expose fresh paper, paint it again or
the paper will absorb moisture from the taping compound
and paint and show through later.
Trowel on the compound with overlapping vertical
strokes as we show in Fix No. 6. Then make a series of overlapping
vertical strokes with a knockdown knife to smooth
out tool marks and fill in low spots (Photo 1). Next make a
series of overlapping horizontal strokes, again with the
knockdown knife (Photo 2).Work quickly so the thin coat
of mud doesn’t begin to dry. If you did a good job of applying
and smoothing the joint compound, you’ll only need
one coat. But if after sanding the wall, you find some uneven
areas, trowel on more taping compound wherever it’s needed
to fill in problem spots and sand again. |
Click Image to enlarge.
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