A drywall patch nobody can find is mostly about the paint

Quick answer: Match the method to the size of the hole. Spackle for anything smaller than a dime, a mesh patch up to about four inches, and a piece of new drywall for anything bigger. Then feather wide, sand under a flashlight, prime the patch, and repaint the whole wall if you can. Most patches that show aren't bad patches. They're bad paint jobs.

Last spring a friend's fourteen-year-old flung his bedroom door open hard enough to put the knob straight through the wall. A neat round hole, two and a half inches across, at hip height, right where everyone walking down the hall would see it. She was quoted a minimum service call by a handyman. She fixed it herself that weekend for the price of a mesh patch, a tub of joint compound and a twelve-dollar door stop.

You can do the same. You just have to know which of four jobs you're actually looking at.

Nail holes, anchor holes and dings

This is the easy one, and it's still where people get it wrong.

Buy lightweight spackle. DAP DryDex goes on pink and turns white when it's dry, which takes the guessing out of it. Load a little on a flexible putty knife about an inch and a half wide, press it into the hole, then pull the knife flat across the wall so you scrape off almost everything you just put on. You want the hole filled and the wall around it clean.

The mistake is leaving a little mound "to sand later." That mound becomes a halo you can see from across the room.

Plastic wall anchors should come out first. Grip them with needle-nose pliers and twist. If one won't budge, push it into the wall cavity with a nail set and fill the hole over it.

Screw pops are the other small one. That's when a drywall screw works loose and leaves a little bump or crack. Drive a new 1¼-inch drywall screw about an inch and a half above or below it so it pulls the board tight to the stud, then sink the old screw just below the surface and spackle both.

Up to about four inches: the mesh patch

Doorknob holes, the corner of a dresser, a towel bar that ripped out. Self-adhesive patches come in 4-, 6- and 8-inch squares with an aluminum plate behind fiberglass mesh, and they're the right tool for this size.

1. Trim any torn paper and crumbly gypsum around the edge with a utility knife. Loose paper bubbles up under compound later.
2. Stick the patch over the hole, centered, pressed flat.
3. Skim a thin coat of all-purpose joint compound over it with a 6-inch knife. Thin enough that you can still see the mesh pattern. That's correct.
4. Let it dry overnight. Then a second coat with a 10-inch knife, wider than the first. Then a third, wider again.

Each coat should reach a few inches past the last one, and the final coat should end up something like a foot across on a four-inch patch. That's what "feathering" means. The patch sits slightly proud of the wall because of the mesh, and the only way to hide that's to spread the change in height over a wide area so your eye can't find the edge.

If you're impatient, use setting compound instead of premixed. Sheetrock Easy Sand comes in 5-, 20-, 45- and 90-minute versions. The 45 gives you time to work and lets you put a second coat on the same afternoon. Only mix what you'll use in that window. Once the clock runs out, it hardens in the pan, done or not.

Fist-sized and bigger: new drywall

Past about five inches, a mesh patch flexes when you press on it. You need a real piece of board.

Before you cut anything, look inside. Shine a flashlight into the hole. Wires, pipes and ductwork live in walls, and the ones near outlets and switches are the ones you'll hit. If you're working anywhere near electrical, shut off the breaker for that room first.

Most interior walls are half-inch drywall. Ceilings and garage walls are often five-eighths. Measure the edge of the hole to be sure. Home centers sell 2-by-2-foot panels so you don't have to haul a full sheet home.

The method that works for nearly everyone:

• Square up the hole with a jab saw. A clean rectangle is far easier to fill than a ragged circle.
• Cut two strips of 1x3 lumber a few inches longer than the hole is tall. Slide them inside the wall behind the left and right edges and screw through the drywall into them, one screw near each end. Now you've got something to fasten to.
• Cut your new piece to fit the opening with about an eighth of an inch to spare all around. Screw it to the strips, heads just below the surface without tearing the paper.
• Tape the seams. Paper tape bedded in compound is stronger. Mesh tape is easier. Either is fine for a patch this size.
• Three coats, each one wider, same as above.

Old hands use a "California patch" instead, where you peel the gypsum off the back of an oversized piece and use the leftover face paper as built-in tape. It's faster once you've done a few. Your first time, the backer strips are more forgiving.

Sanding: turn off the overhead light

Use a medium-fine sanding sponge, not a block with coarse paper. Coarse paper scuffs the face of the surrounding drywall and raises fuzz that shows through paint.

Then the trick nobody tells you. Turn off the room light and hold a flashlight flat against the wall so the beam skims across the patch. Every ridge and dip throws a shadow. What looked perfect at noon looks like a topographic map. Mark the low spots with a pencil, skim them, sand again.

A damp sponge cuts the dust. Wear a dust mask either way. Joint compound dust gets everywhere, and it'll be in the hallway closet in a month if you don't close the door and lay a drop cloth.

Prime it, or it'll flash

Bare joint compound drinks paint differently than the painted wall around it. Skip primer and you'll get a dull patch on a satin wall, visible only when the light hits it at an angle. Which it will, every afternoon at 4 p.m. That's called flashing, and it's the single most common reason a perfectly flat patch still shows.

Spot prime the patch and the feathered area with a drywall primer. Let it dry fully.

If your walls have orange-peel texture, spray-can texture exists for exactly this. Practice on a piece of cardboard first. The first burst always comes out heavier than you expect.

Why your touch-up won't match, and what to do about it

You found the leftover can in the garage, it's the right color, and the patch still looks different. Paint fades on the wall and changes in the can. Sheen matters as much as color. A brush leaves a different surface than the roller that painted the rest.

So:

• Use a roller with the same nap the wall was painted with, not a brush.
• If the leftover can is old or you don't have one, take the cover plate off a switch on that wall and cut a small chip of painted drywall from behind where it won't show. A paint store can match from that.
• Best of all, paint the whole wall from corner to corner. Your eye reads a wall as one surface and forgives a slight difference between walls. It won't forgive one inside a wall.

That last step feels like overkill when you're tired. It's also what separates a repair you can see from one you can't.

When to call someone

If the drywall is soft, stained or smells musty, the hole isn't the problem. Something's leaking, and you need a plumber or a roofer before you need a knife. A ceiling sagging between joists is a pro job. And if you're looking at a whole wall of damage, a good drywall finisher will do in a day what takes you a week. Finishing really is a craft. Paying for skill is sometimes the smart call.

If you rent, read your lease before move-out. Many landlords are glad to have nail holes filled. Some would rather do it themselves. Either way, a clean, primed patch beats a hole every time.

And when you're done, fix whatever made the hole. A rubber door stop on the baseboard takes four minutes to install. My friend put one on every door upstairs, not just her son's. The hall's been fine ever since. So has the son, who now knows how to patch drywall, because she made him help.