The Doorknob Hole in the Hallway, Fixed the Way It Really Goes

Quick answer: Nail holes get spackle and you're done. A doorknob-size hole gets a square cutout, wood backing, a drywall patch, tape and three thin coats of compound, sanded, primed and painted. Budget about forty dollars and a weekend, because most of the time is spent waiting for mud to dry.

The hole in my hallway is the exact shape of a brass doorknob. It got there because a door swung open hard, and the door had nothing to stop it, because the door stop was "on the list." It was on the list since spring. My wife mentioned it in March, April and once in June with a drawing. She was right every time.

What the box says

"Repair holes in minutes! Apply patch, spread compound, paint. Invisible results."

What you will actually need

• Drywall saw (jab saw). Around ten dollars.
• Utility knife with a fresh blade.
• A scrap of drywall the same thickness as your wall, usually 1/2 inch. Hardware stores sell 2-by-2 foot patch panels for about ten to fifteen dollars, or a full 4-by-8 sheet for not much more if you own a truck and optimism.
• Two strips of 1x3 lumber or scrap plywood for backing, a few inches longer than the hole.
• 1 1/4-inch drywall screws and a drill.
• Mesh or paper drywall tape. A few dollars.
• Joint compound. A small bag of setting-type compound (the 20- or 45-minute kind) for the first coat, and a tub of premixed lightweight for the finish coats. Ten to twenty dollars total.
• Putty knives: a 6-inch and a 10- or 12-inch. Ten to fifteen dollars each.
• Sanding sponge, medium-fine (120 to 150 grit), and a dust mask.
• Stud finder with live-wire detection, and a flashlight.
• Primer. This is the thing everybody forgets and drives back for. Paint over bare compound without it and the patch will glow through like a lighthouse.
• The actual paint. Not the can in the garage marked "hall??" from 2014. That can is lying to you.

The steps

1. Look before you cut. If the hole is anywhere near an outlet, switch or light, shut off that circuit at the breaker panel and confirm it's dead with a non-contact voltage tester. Shine a flashlight into the hole and check for wires, pipes and ductwork. Run the stud finder along the area. On a bathroom or kitchen wall, assume there's plumbing until you see otherwise.

1. Draw a square around the damage with a pencil and a level, a little bigger than the broken part, then cut along the lines with the drywall saw. Keep the blade shallow. Short strokes.

You'll want to cut a perfect circle around the round hole. Don't. Squares are easy to match. Circles are how you lose a Saturday.

1. Install the backing. Slip a wood strip inside the opening so it overlaps the top and bottom edges by an inch or two. Hold it tight and drive a screw through the wall into each end. Do the same on the other side.

Drive a screw halfway into the middle of the strip first and use it as a handle. Otherwise the strip falls into the wall, and you'll hear it land somewhere near the basement, forever.

1. Cut the patch to fit the opening with about 1/8 inch of gap all around. Score the face with the utility knife, snap it, cut the back paper. Screw it to the backing so the heads sit just below the surface without tearing the paper.

If a screw rips through the paper, it's holding nothing. Add another an inch away.

1. Tape and fill. Mix the setting compound to about peanut-butter consistency. Fill the gaps, lay tape over all four seams, and press compound through and over it with the 6-inch knife. Scrape it smooth and thin. Wash your tools right away. Setting compound hardens on its own schedule, not yours.

1. Second coat, once the first is hard. Use premixed lightweight and the wide knife. Spread it a few inches beyond the first coat on every side, pressing hard on the outer edges so they taper to nothing.

1. Third coat, wider still, thinner still. Let it dry overnight. Premixed compound needs real drying time, and humid weather adds more.

This is the step where you poke it at hour three to check. It leaves a fingerprint. You'll be sanding that fingerprint later.

1. Sand lightly. Wear the mask, because joint compound dust gets everywhere and you shouldn't breathe it. Hold a flashlight flat against the wall so the light rakes across the patch. Every ridge throws a shadow. Sand those, not the paper face around them.

Lay a drop cloth down first and close the HVAC vents in that room. The dust will still end up in the kitchen. It always ends up in the kitchen.

1. Prime, then paint. Prime the patch, then roll on paint with a roller, not a brush, so the texture matches the rest of the wall. If you can, paint the whole wall corner to corner. A patch painted alone often shows as a slightly different sheen, even with the right color.

1. Install the door stop. Two dollars, two minutes. Ask me how I know.

Where it goes wrong

The patch shows as a bump. Too much compound, not enough width. A patch hides by being wide and gradual, not by being thick. Sand down the high spot and add a thin coat that runs 10 or 12 inches past the edges.

A crack shows up along the seam a month later. Somebody skipped the tape or the backing, and the patch is moving. Cut the cracked compound out, screw the patch tight, tape it, and recoat. If you've got a chair that keeps tipping back into the same wall, reglue the wobbly chair while you're at it, or you'll be doing this again by Christmas.

The wall is textured and your patch is smooth. Most walls have orange-peel or knockdown texture. Spray-can texture sold at hardware stores matches it surprisingly well. Practice on a piece of cardboard first, and start lighter than you think. More detail on the smaller jobs is in Patching Drywall Without Making It Worse.

When to call a pro

• There's a water stain, soft drywall or any sign of mold. The hole is the symptom. Find and fix the leak first, which may mean a plumber or roofer, then replace the damaged board.
• You hit a wire or a pipe. Stop. Call a licensed electrician or plumber. Don't tape over it and hope.
• The house was built before about 1980. Older joint compound can contain asbestos, and paint from before 1978 may contain lead. Get the material tested before you cut or sand.
• It's a big ceiling hole. Overhead patches are heavier, harder to support and often 5/8-inch board.
• It's the wall between the garage and the house. That wall is usually fire-rated and often requires Type X drywall. Codes vary by area, so check with your local building department or hire a drywall contractor.
• The hole is bigger than a couple of feet. At that point it's a board replacement, and a pro will finish it in a fraction of your time with none of the dust in your kitchen.

Then go put a door stop behind every door in the house. It's the cheapest drywall repair ever invented, and it's been sitting in a drawer since March.