Wall Repair and Fasteners
Plaster or dry wall is commonly used for walls. Other
decorative materials such as plywood paneling, paper, or
just paint are used to help the appearance of the wall.
Unfortunately, common fasteners do not perform too well
when used on plaster and result in holes or cracks which
are unattractive. Settling or shrinking of walls also
cause cracks. For more information see Extension bulletin
E-816.
Patching A Wall
Popping Nails - The heads of nails used to fasten plaster
board to studs often pop out. This is caused by moisture
changes in the studs which squeeze the nail out.
To remedy popped nail heads, first drive additional
nails about 2" above and below the popped nail head.
Drive the nails, including the popped nail, until a
dimple shows around the head. Be sure you hold the
plasterboard tight to the stud. Dust off all
loose paint and plaster and fill the dimple with patching
plaster using a wide putty knife. Let dry and if patch
shrinks re-apply patching plaster. When patch is
completely dry, sand with fine sandpaper and paint.
Small Cracks - Small, narrow cracks can be filled with
patching plaster. First remove loose plaster and with an
icepick or knife, clean the crack so it is wider at the
bottom than on the surface. This allows the new plaster
to stick better. With a brush or damp cloth remove loose
plaster dust. If water mixed plaster is used dampen the
crack.
Fill the crack with patching plaster using a criss-
cross motion to work it in. With the wide putty knife
feather the edges of the patch, about 2" on each side of
the crack, so it will be less visible. When dry sand
lightly and paint.
Large Cracks - When the crack is large the wet plaster
will not stick. If this is the situation buy a roll of
patching tape at a paint store. Clean off all loose
plaster. Fill the crack with plaster and press the
perforated tape into the wet plaster with a wide putty
knife. Squeeze out any excess plaster so there will not
be a lump in the wall. Let it dry, sand lightly and
paint. A coat of sizing will make the paint stick better
and look better.
Holes Through Wall - If there is a large hole through the
wall patching plaster will not stick. Two methods can be
used:
(1) The first method.
Mark a rectangle on the wall which includes the
hole. With a knife or key hole saw cut out the rectangle
being careful not to break it. On a scrape piece of
plaster-board copy the section of wall. Then mark a frame
about 2" wide around the section of wall. This is the size
of patch to cut. After cutting remove the paper on one
side and the plaster from the frame around the patch The
2" frame of paper will stick out like an ear all around
which will hold the patch in place. Spread patching
plaster around the edge of the hole and around the edge of
the patch. Put the patch in the hole and press the paper
ears into the plaster and hold it while it sets. Sand
lightly and paint.
(2) The second method.
Cut a piece of metal plaster lath or heavy screen
larger than the hole. Fasten one or two wire ties to the
lath and insert through the hole. Pull the lath up behind
the hole and wire to a stick of wood placed across the
hole on the front side of the wall. Moisten the edge of
the hole and spread a base coat of patching plaster to
within 1/8" of the finished surface. Roughen the surface
with a stick or nail so the finish coat will stick, After
the base layer is dry remove the stick and clip the wires
close to the surface. Trowel on the finish layer being
sure it is flush with the wall surface. Let it dry good
and then paint. If the patched area is large apply a coat
of sizing before painting.
Fastening to Plaster Walls
Lightweight Object or Pictures - Very lightweight objects
can be supported with a piece of tape. The wall
must be smooth, clean and dry. The glue is affected by
humidity and may let loose so do not hang anything that
will break with this kind of fastener.
Objects with a wide variety of weight can be
supported by a metal hook on a long tapered nail driven
at an angle into the plaster. These come in
packages of three or four and in different sizes depending
on the weight to be supported.
Medium Weight Objects- Some kind of insert, plastic,
fiber, wood. or lead can be used with a sheet metal
screw. Drill a hole just large enough to be able
to tap the insert into the hole. Tap the insert into the
hole until it is flush with the surface. Turn a sheet
metal or wood screw into the insert. Usually these inserts
come packaged with the right size screw for the particular
insert. It will also tell you what size hole to drill.
Heavy Objects - Heavier objects can be supported with a
molly bolt or toggle bolt. Drill a hole through
the wall to fit the size of molly bolt -- be sure not to
get the hole too big or you may have difficulty turning
the bolt without having the connector turn. If the only
drill is too small, use a small screwdriver, knife, or
other object to ream out the hole until the fastener will
slide in snugly. Push it in and turn the bolt clockwise
until it feels tight. Now the fastener has expanded and
should stay tight Remove the bolt and attach the object
screwing the bolt in tight. Do not over tighten or you may
pull the fastener loose. Remember plaster is soft.
A toggle bolt can be used similar to a molly bolt but
with less care taken when installing. Select a bolt long
enough to include the object plus the wall plus the
length of the toggles when folded up. Drill a hole
through the wall. If you do not have a drill: Drive a
nail through the wall. Wiggle it until it comes loose and
you can pull it out. Put a small screwdriver, knife, or
piece of metal into the hole and carefully enlarge until
the toggle will slide through. Assemble the object on the
bolt and push the toggle into the hole until you can feel
it spring open. (Now you cannot remove the bolt without
losing the toggle in the wall). Tighten by turning
clockwise.
A toggle bolt should be used where the object will be
drawn up tight to the wall because the hole must be large
enough to receive the toggle. The object should be large
enough to cover the large hole that is necessary.