Drywall Repair and Maintenance
Drywall, also called wallboard, gypsum board or plasterboard, is often simply known by the brand name Sheetrock. It consists of a hard gypsum core sandwiched between piles of fiberboard, paper or felt. Drywall is sold in a 4 by 8 or 4 by 12 foot sheets that are nailed or screwed to studs.
Just as the classification for drywall varies, so do the names of the plaster like substances used for sealing drywall. The substance most commonly used to finish joints is called joint compound. When you have the time, use this for making repairs. It applies smoothly and sands beautifully. The disadvantages are: it takes 24 hours to dry and it shrinks while drying, so you need two or more layers to level off a wall surface. There are also a variety of other patching substances. Spackling compounds dry faster and shrink less but are harder to sand smooth. Patching plasters dry quickest (one to two hours) without shrinking and are strong fillers, but dry hard and are difficult to sand. If you use one of these, fill a hole almost flush with the wall, then finish with join compound for easy sanding.
Small dents of up to one inch can simply be filled with joint compound or patching plaster, and sanded. If nails have popped through the surface of your wall, remove these or sink them with a hammer and nail set, drive a new screw an inch above or below the old nail, then fill the new dents.
Patching with wire screen is a good method for repairing holes from one to five inches or so. Cut the screen patch slightly larger than the cleaned-out hole.
If you can get your fist through the hole but it is no more than about 8 inches, use a beveled patch cut out of an extra piece of drywall. Measure the damaged area and add one inch in each direction for the patch dimensions. Use a drywall saw to cut the edges of the patch slanting in (beveled) so that the inner surface is smaller than the outer.
A break that is more than eight inches in any direction will need a backer board or two for supporting new drywall. Use 1×2’s or 1×4’s – whatever you have handy. Just make sure they are five inches longer than the opening and provide a flat surface to support a new patch.
What you will need:
Metal straightedge
Tape measure
4″ and 6″ joint knives
shears
Drywall sandpaper
Sanding block
Drywall saw
Dust mask
Utility knife
Phillips-head screwdriver
8″ joint knife
Materials:
Drywall scraps for patches
Drywall tape
Joint compound
Drywall patching plaster
Piece of wire screen
String
Masking tape
1×2 or 1×4 for backer boards
Drywall screws
Construction adhesive
Drop cloth
Small repairs:
Joint compound for dents. Clean off loose edges. Dip joint knife into compound sideways and load about half the blade width. Pull knife across dented area with a slow smooth stroke. Position knife at a 90-degree angle to the first stroke and pull across again to remove excess compound. When dry, sand to finish.
Iron-on patches for small holes. These patches are a great method for repairing small flaws in drywall. Cut the polymer fabric to size and iron with a household iron set at medium heat. Apply compound over fabric and sand when compound has dried. Always wear a dust mask while sanding joint compound.
Patching holes 1 to 5 inches. Clean away loose drywall and cut off loose paper. Leave the inner surface of the gypsum rough. Cut screen 2 inches larger than hold all around. Tie one end of 12-inch string to a small stick; thread other end through center of screen.
Bend screen and insert stick and screen into hole. Pull on string so the stick holds screen flat against back of hole. Holding string taut, fill hole, working in from the edges. Make sure compound adheres to mesh. Tape string tightly against wall with masking tape.
When compound has dried completely, cut string flush to wall. If using joint compound, remember it will shrink; apply another layer to bring patch up to surface of wall. You may have to apply a third layer. Then proceed to finishing.
Patching holes 5 to 8 inches. Measure a rectangular drywall patch about an inch larger than the hole. Cut it at a bevel with drywall saw, or use a saber saw with angled base plate. Use patch as a template to mark wall, and cut around hole at same bevel as patch.
After adjusting it, if necessary, with a utility knife, spread compound along the beveled edges of the patch. Fit patch in place with light pressure. Matching bevels prevents patch from falling through.
Smooth the compound and apply drywall tape over all joins with the joint knife. At end of each joint, press edge of knife blade in firmly and use a straightedge to tear off tape. Sand when dry.
Patching larger holes with backer boards. Measure hole. Cut a rectangular or triangular patch from a piece of drywall making it at least 1 inch larger than the hole on all sides. Trace patch onto wall and cut out shape using saw or utility knife.
Insert a backer board with construction adhesive applied to the ends. Holding firmly in place, screw drywall screws through drywall into board, at least 1 inch away from edge of hole. Repeat if using two backer boards.
Place the new piece of drywall in the hole and fasten it to backer boards with screws. Press compound or fast drying patching plaster into joints with joint knife. Tape joints and finish.
Finishing after repairing. No matter how small or how large the repair, the method for finishing is the same. With wide joint knife spread a smooth, thin layer of joint compound over the repaired area or over all joints of new patch. Extend beyond edges of repaired area and feather out to surrounding wall.
When compound is dry (at least 24 hours), sand with fine-grade drywall sandpaper on a sanding block. Wear a dust mask when sanding. If necessary, repeat these two steps until satisfied with your final surface.
