| In
This Article:
The broken drywall is cut
back, a new piece of wallboard is screwed in place, and the
joints are filled with mud. |
Related
Articles:
|
| Skill Level:
2 (Basic) |
Time Taken:
2 Hours |
By
Bruce W. Maki,
Editor
 |
A section of wall had a series of fist-sized holes,
covering an area about 2' by 2'.
The procedure is to cut out the affected area and attach a
new piece, and then fill in the edges with drywall joint
compound to make it smooth. |
My objective was to get the left edge of the patch to fit under
the window trim, so there would be one less edge to finish, which
would reduce the chances of a crack occurring later on.
 |
There were also several screw heads popping through the
surface. They show up as little bumps...
...but underneath the screw head is visible. I drove these
in tight with a screwdriver. |
 |
 |
The window trim was pried away from the wall. See that
story.
I broke away some of the wallboard to find the stud at the
right hand edge of the hole. |
 |
I marked the wall where the new piece of drywall would go, making
sure that the right hand edge would fall in the center of the stud.
 |
I used a drywall saw to make the cuts.
And then a sharp knife was used to finish the cuts at the
corners. |
 |
 |
The damaged drywall was peeled away.
The hole after most of the damaged section was removed.
There is still a thin strip to be removed along the right
side. |
 |
 |
Any screws that were exposed were removed. There were a
couple of screws under the window trim. These were broken off
by striking them with a pry bar.
The drywall edge was beveled with a sharp knife. |
 |
The sharpness of the knife is very important. I use inexpensive snap-off
blade knives (3 for $1 at Sears, when available). There are many
brands available, two common brands are Olfa and Tajima. I stay away
from the usual retractable utility knives, but with a new
blade they should work for this task.
 |
The beveled edge, about 1/2" wide.
A piece of drywall was fitted into the opening. |
 |
Before going any further, I added a piece of wood behind the
hole. This is a common technique to provide backing for a drywall
patch that is not big enough to span between two or more studs.
 |
I placed the piece of 1x3 against the hole, to make sure it
extended above and below the hole by a foot or so. (The clamp
was only needed so I could step back and take a picture.)
The stick was slid downward behind the drywall and
then up behind the top section. A few 1-5/8"
drywall screws secured the board. |
 |
 |
The patch was installed with a few drywall screws.
There was a 1/4" gap along the lower edge. It can be
filled with joint compound. |
 |
Joints in the middle of a wall will probably crack eventually,
unless tape is used to span the joint. Tape is available in paper
and fiberglass mesh. The fiberglass mesh is stronger but thicker, so
it is harder to hide under joint compound.
 |
The paper tape is too wide for the small bevel I made, so I
cut it narrower.
The tape was a little less than half it's original width. I
also made a fold down the middle. |
 |
Applying The Joint Compound
 |
This very crucial tool comes straight from the kitchen: a
curved rubber spatula. I use it for mixing joint
compound...
...and applying mud to the beveled joints. It leaves a
nicely recessed trough. |
 |
 |
The joint after being filled with mud, and then wiped
smooth with the spatula.
The tape is applied and pressed in place with a putty
knife. (Actually the spatula worked better.) |
 |
 |
More joint compound was applied over the tape. The goal is
to completely cover the tape so it never shows through.
A 6" putty knife was used to smooth the mud. |
 |
After this application, the joint compound was allowed to harden.
I always use 20 minute setting type joint compound, the
fastest hardening compound available. 20 minutes refers to the
working time before it gets too stiff. It can take several hours to
harden if, as in this case, there are some very thick spots.
I have several pails of pre-mixed joint compound hanging
around the shop, where they'll likely stay. Pre-mixed mud can take
several days to dry when it is applied in a thick section. I
don't have that kind of time.
Pre-mixed is most useful for doing large drywall finishing jobs:
entire rooms or entire houses.
Setting type compound is the best for patches. It is a dry powder
that has to be mixed with water to a thick and creamy consistency.
Sanding The Hardened Joint Compound
 |
After a couple of hours most of the drywall compound was
dry. The test I use is to scratch the surface. If the scratch
appears as a lighter color, it may be ready to sand, even
though it appears damp.
The sanding screen has holes that allow the dust to fall
through. |
 |
 |
This device is a sanding screen holder that
attaches to a wet/dry vacuum. It picks up perhaps 90% of the
dust. An excellent tool, worth it's weight in gold. When using
this attachment the shop vac needs to have it's filter cleaned
frequently. |
Drywall sanding is easy but tedious. If the joint compound is
applied reasonably thin, then minimal sanding will be needed. The
joints are sanded until they are "feathered" or smoothly
blended into the adjacent surfaces.
 |
The two taping knives used. The 8" knife on the left
was used for the second coat, and the 14" knife was used
for the last coat.
The second coat is simple: apply thin and smooth. |
 |
Since the second and third coats were so thin, they dried within
an hour.
 |
After applying the second coat of mud, the joint locations
were visible.
After the third coat the mud spanned from top joint to
bottom joint. Upon drying the wall looked smooth. |
 |
 |
After the third coat of mud had dried it was sanded and
primer was applied using a small roller.
Drywall and drywall joint compound must be primed or
else the paint will soak in deep and leave an obvious spot.
Afterwards the window trim was pushed back in place and
nailed. |
Notes:
Doing a quality drywall finishing job takes a lot of practice.
This is not beyond the skill of most homeowners, just beyond the
patience level of many people. I did not become proficient at
drywall finishing until I built an addition and bought a selection
of professional-grade tools.
Without a doubt, inside corners are the hardest to finish.
Special corner tools are made for smoothing the mud, but they are
tricky to use.
For butt joints (edges that do not have the factory-made taper)
the best solution seems to be the above approach of cutting a wide
bevel and applying a narrow paper tape.
|
Tools
Used:
- Cordless Drill/Driver
- Drywall Saw
- Sharp Knife
- Putty Knives: 1",
6"
- Drywall Taping Knives:
8", 14"
- Drywall Sanding Screen
|
Materials Used:
- ½" Drywall Scraps
- 1-5/8" Drywall Screws
- 20 Minute Setting-Type
Joint Compound
- Drywall Joint Tape
|
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