Whether you're fixing the result of an accident or filling in nail holes from the previous owner, repairing small holes in the wall is an important skill every homeowner should know. Before you begin, you'll need to buy the right filler for the job, and there are two general categories of fillers. Read about the various fillers below and learn how to patch holes in a wall as well as repair nail holes.
What You Need:
- Patching plaster
- Putty knife or chisel
- Broad knife
- Dusting brush
- Latex bonding agent
- Sanding paper
- White-pigmented shellac
How to Patch a Hole in the Wall
Step 1: Apply Bonding Agent
Remove loose material with a putty knife or chisel. Dust the area with a dusting brush. Dampen the edges of the plaster with a commercial latex bonding agent; mix and apply it according to the manufacturer's instructions.
Step 2: Apply and Score Plaster
Mix patching plaster according to the manufacturer's instructions. Apply the plaster with a broad knife. If the hole is less than 1/8 inch deep, one coat should be enough for good coverage. If the hole is deeper, apply a base coat of plaster in the hole to within 1/8 inch of the surface. Press the plaster into the lath. Let this coat set for 15 minutes, then score the surface with a nail to provide tooth for the next layer. Let the base dry overnight.
Step 3: Apply Layers
Apply a second layer of patching plaster, bringing it almost to the surface. Let this layer set for one to two hours to harden. Then, add water to bring the patching plaster to a creamy consistency for the finish coat. Apply the finish coat as smoothly as possible. Make the patched area flush with the surrounding surface. Let the finish coat set for 30 minutes to an hour.
Step 4: Apply and Smooth Finish Coat
Smooth the patch with a damp sponge, blending it into the surrounding surface. This will reduce the amount of sanding necessary. Let the plaster harden.
If necessary, apply a texture coat to replicate existing wall surfaces. Blot the patch with a damp sponge, matching it to the surrounding surface. Let the plaster harden. Lightly sand and seal the area with white-pigmented shellac.
How to Fill Nail Holes
Painted finishes: When you're working with a painted finish, you have a good deal of leeway on the timing of the filler. You can fill holes in raw wood or even after a color coat.
There are two general categories of fillers. One is a dry powder that you mix with water: Durham's Rock Hard Water Putty is one brand. The other —available in cans or tubes—is premixed with solvent such as Plastic Wood. Although the solvent-base product has a slight advantage in convenience, it costs considerably more than the powdered type. Evaporation during storage can solidify the unused solvent product, further boosting its expense. If kept dry, the powder form has exceptional longevity.
Applying both filler types is virtually identical. Pack every hole full, then leave a slight mound of extra material to compensate for shrinkage. When the material is dry (the powdered type dries more rapidly), lightly sand the surface to bring the filled hole flush with the surrounding wood. Proceed with the primer and color coats.
Clear finishes: Filling holes in a clear finish introduces an additional complication -- matching the color of the wood. Do not believe any advertising that claims wood filler will accept stain and finish like genuine wood.
To see the true filler colors you'll need, first stain the raw wood, if desired, then apply the initial clear coat. Take a sample of the stained and coated wood to the paint store and purchase at least two shades of colored putty—one that approximates the deepest tone of the wood and one that's a close match for its lightest portion. When you get home, scoop out a chunk of each shade and knead them together, but leave the combination slightly streaky. Scoop out a ball of straight dark putty and one
How to Fill Nail Holes on a Painted Finish
Slightly overfill holes to allow for the filler's shrinkage. A sanding block will remove the excess while keeping the surface flat.
How to Fill Nail Holes on a Clear Finish
Buy light and dark putty, then mix the two together to create a medium tone. Rub some putty over a hole, pushing in to firmly seat the putty, then wipe off the excess with your finger (wear rubber gloves). Apply at least one more coat of finish to seal in the putty and give it a sheen that matches the surrounding wood.
Use a Marker to Fill Nail Holes
Some stain manufacturers also package stain in a felt-tip pen that makes touch-ups fast and easy. Use it at miters that are slightly misaligned or to eliminate the raw look from exposed cut ends. Choose a light tone for end grain because its absorption makes stain appear darker. Draw the marker across the wood, then buff it quickly with a paper towel. Keep the marker handy to minimize the appearance of surface scratches on woodwork.
Apply Putty to Fill a Nail Hole
The usual putty-application procedure involves simply rubbing your finger over the hole. But if you've installed several rooms full of trim, you can easily rub your fingertip raw before completing the job. Also, your finger can slightly dip into the hole, creating a slight depression. Use an ordinary kitchen spatula as a solution. It's firm enough to wipe away excess putty and leave a smooth surface. It also conforms to curved surfaces, speeding your work.