What's the best way to repair a small drywall cut left after electrical work?

Direct answer

For a small drywall cut left after electrical work, the best repair is to square up the opening, add a backer (wood strip or drywall repair clips), screw in a matching drywall patch, tape and mud the seams with setting-type compound, then sand, prime, and paint. For very narrow slits (under about 1/2 inch), you can often fill with setting compound and tape without adding a patch.

Why this works

Electrical fishing often leaves thin slots or small rectangular openings that don’t line up with studs. Drywall needs support at the edges to stay flat and crack-free. A backer gives your patch something to bite into, and using setting-type compound ("hot mud") minimizes shrinkage and speeds up the process. Proper priming ensures the paint blends without flashing.

Typical specs:
- Drywall thickness: 1/2" on most interior walls, 5/8" on ceilings/garages
- Screw length: 1-1/4" coarse-thread for wood studs/backers
- Screw spacing on patch: every 6–8"
- Feather width for final coat: 8–12" beyond the joint

What you’ll need

• Drywall scrap matching thickness (1/2" or 5/8")
• Backer strips: 1x2 furring, paint stir sticks, or drywall repair clips
• Joint compound: setting-type (20 or 45 minute) for first coats, lightweight ready-mix for finish
• Tape: paper tape for strongest joints; fiberglass mesh is fine if used with setting compound
• Cutting tools: utility knife, drywall saw or oscillating multi-tool
• Fasteners: 1-1/4" coarse-thread drywall screws
• Taping knives: 4–6" for embedding, 10–12" for feathering; mud pan
• Sanding: 120–220 grit sanding block or sanding sponge; optional dustless sander with HEPA vac
• Primer: PVA drywall primer; matching paint
• Optional: self-adhesive aluminum mesh patch for holes up to ~3"
• Safety: eye protection, dust mask/respirator (N95/R95), voltage tester

Approximate cost: $20–$50 in materials if you don’t already have them. Time: 2–6 hours spread over a day, depending on compound dry times.

Step-by-step: rectangular slot or small cut (1–6 inches)

1. Assess and make safe

   • Turn off the circuit you were working on. Use a non-contact voltage tester around the cut and box.
   • Gently pull wires back into the box so you don’t screw into them.

2. Square and clean the opening

   • Use a utility knife or oscillating multi-tool to square up the hole to clean, straight edges. A neat rectangle is easier to patch.
   • Bevel the drywall edges slightly (45°) to create a shallow trough for compound.

3. Add backing

   • Cut two backer strips about 2" longer than the opening width.
   • Insert one strip behind the top edge, hold it centered, and drive two screws through the face of the drywall into the strip (one on each side of the opening). Repeat for the bottom edge. Keep screws at least 3/4" from any electrical box and cable path.
   • Alternative: Use drywall repair clips at the corners.

4. Fit the patch

   • Cut a piece of drywall to fit the opening. Aim for a snug fit with a paper-thin gap.
   • Screw the patch into the backers (and clips if used) until screw heads are just dimpled without tearing the paper.

5. Tape and first coat

   • Prefill any gaps over 1/8" with setting-type compound.
   • Apply a thin bed of setting compound over seams, embed paper tape, and wipe tight with a 6" knife. Cover screws.
   • If you prefer mesh tape, use it only with setting compound to reduce cracking.

6. Build coats

   • After the first coat sets, apply a wider second coat (8–10"). Use a 10–12" knife to feather edges.
   • Apply a third skim as needed with lightweight ready-mix for an easier sand.

7. Sand, prime, and paint

   • Lightly sand high spots; avoid over-sanding the paper. A damp sponge can knock down edges with less dust.
   • Prime with PVA primer over the repaired area (or corner-to-corner on the wall for best blend), then paint to match.

Very narrow slit (under ~1/2")

• Brush out dust. Pack setting-type compound into the slit.
• Apply mesh tape over the slit, then a thin coat of setting compound. Feather 6–8".
• Follow with a finish coat, sand, prime, paint.

California (butterfly) patch option (skill-friendly, no backers)

• Cut a patch larger than the hole by 1–2" each way. Score and snap so the gypsum matches the opening size while leaving a 1–2" paper “flange” around it.
• Trace the gypsum center of your patch on the wall and cut out to fit.
• Spread compound around the hole, press the patch so the paper flange glues to the wall, embed edges with more compound, then skim and feather. Works well for holes up to about 6" where backer access is tight.

Safety and working around electrical

• Power off and verify with a tester.
• Keep screws clear of cable runs; do not drive fasteners into the box cavity.
• Wear eye protection and a dust mask; use dust control sanding or a HEPA vac when possible.

Tips for best results

• Use setting-type 20 or 45 for the first coats to reduce wait time and shrinkage.
• Feather wide. Wider, thinner coats are easier to hide than thick, narrow ones.
• Match textures before priming: light orange peel (aerosol texture), knockdown (spray then knock down after set), or hand textures.
• Work under raking light to spot ridges and fill low areas.
• Prime the repair with PVA to prevent flashing and ensure even sheen.

Common mistakes to avoid

• Skipping backing on anything larger than a narrow slit—leads to cracks and a spongy patch.
• Using only premixed mud with mesh tape—can crack. If using mesh, start with setting compound.
• Overdriving screws and tearing paper—weakens hold and causes pops.
• Over-sanding into paper—creates fuzzy spots that flash under paint. Spot prime if that happens.
• Not priming before paint—sheen mismatch will telegraph the patch.

When to call a pro

• The opening reveals damaged wires, questionable splices, or you’re unsure about cable routing.
• Large holes (over ~12") or multiple patches across a textured wall you need perfectly blended.
• Plaster and lath walls (different methods/materials).

With a few basic tools—a utility knife, a couple of taping knives, setting compound, and either backer strips or a California patch—you can make a small electrical cut disappear in an afternoon and be ready for paint by evening.