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Fix a wall that has a crack

We'll confirm the crack type and size, rule out structural damage, then patch hairline cracks with spackle or wider cracks with joint compound—or tell you when to call a pro.

Troubleshooting · Home maintenance
30–90 min
What you'll need
  • Spackle (for hairline cracks)
  • Joint compound and mesh tape (for wider cracks)
  • Putty knife or taping knife
  • 120-grit sandpaper
  • Primer and paint (to match the wall)
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Steps

Goal: Confirm the crack pattern and size, rule out structural damage, then patch or call a pro.

  • Inspect the wall. Note whether the crack is hairline, vertical, stair-step, or horizontal—and whether it is in drywall or plaster.
  • Good: Crack visible—proceed to Check if it suggests structural issues.
  • Bad: Wall looks intact—you may have a different problem (hole, stain).

Check if crack suggests structural issues

Goal: Rule out foundation or structural damage before patching.

  • Stair-step cracks in brick or block often indicate foundation movement. Horizontal cracks can mean soil pressure. Cracks wider than 1/4 inch or growing need a pro.
  • If doors or windows nearby stick or bind, that can signal settling. Call a foundation or structural professional to assess.
  • Good: Crack is hairline or narrow vertical—proceed to Hairline path or Wider path.
  • Bad: Stair-step, horizontal, or wider than 1/4 inch—call a pro.

Hairline crack — spackle and paint

Goal: Patch a narrow crack with spackle so it is invisible and stable.

  • Scrape out loose material with a utility knife or small screwdriver. Wipe with a dry cloth. The crack should be clean and dry.
  • Apply spackle with a putty knife, pressing it into the crack. Overfill slightly. Let dry per the product label (usually 1–2 hours).
  • Sand with 120-grit sandpaper until smooth and flush. Wipe away dust. Apply primer, then paint to match the wall.
  • Good: The crack is filled and the surface is smooth—done.
  • Bad: Crack reappears—may need pro or structural assessment.

Wider crack — joint compound and tape

Goal: Patch a wider crack with mesh tape and joint compound so it does not reappear.

  • Apply self-adhesive mesh tape over the crack. Spread joint compound over the tape with a putty knife, feathering the edges.
  • Let dry per the product label. Apply a second thin coat if needed. Sand smooth when dry.
  • Apply primer, then paint to match the wall.
  • Good: The crack is covered and the surface is flat—done.
  • Bad: Crack reappears—call a pro to assess.

When to get help

Call a foundation or structural professional if:

  • The crack is stair-step (in brick or block).
  • The crack is horizontal.
  • The crack is wider than 1/4 inch or growing.
  • Doors or windows nearby stick or bind.

Confirm you have assessed the crack type before calling. For related fixes, see Fix a floor that squeaks or Fix a door frame that is cracked.

Verification

  • The crack is filled or covered and the surface is smooth and painted.
  • The repair blends with the surrounding wall.
  • The crack does not reappear after the patch dries (if it does, call a pro).

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm symptom Note the crack pattern—hairline, vertical, stair-step, or horizontal—and wall surface type.
  2. Rule out structural Stair-step, horizontal, or wider than 1/4 inch—call a pro. Hairline or narrow vertical—proceed to patch.
  3. Hairline crack Clean, fill with spackle, sand, prime, and paint.
  4. Wider crack Apply mesh tape and joint compound, sand, prime, and paint.
  5. Call a pro Structural crack—call a foundation or structural professional.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Crack pattern (hairline, vertical, stair-step, horizontal)
  • Wall surface type (drywall or plaster)
  • Whether the crack is growing or stable
  • Steps already tried

Is there a crack in the wall?

Inspect the wall. Note the crack pattern—hairline, vertical, stair-step, or horizontal—and whether it is in drywall or plaster.

Inspect the wall. Yes: Crack visible—proceed to check if it suggests structural issues. No: If the wall looks intact, you may have a different problem (hole, stain, moisture).

Yes No

You can change your answer later.

Is the crack stair-step, horizontal, or wider than 1/4 inch?

Stair-step cracks in brick or block, horizontal cracks, or cracks wider than 1/4 inch can indicate foundation or structural issues.

Check the crack pattern. Stair-step: Follows mortar joints in brick or block—often foundation. Horizontal: Can mean soil pressure. Wider than 1/4 inch: May be structural. Yes: Call a foundation or structural pro. No: Crack is hairline or narrow vertical—proceed to patch.

Yes No

You can change your answer later.

Is the crack a hairline or wider?

Hairline cracks are narrow and shallow. Wider cracks need mesh tape and joint compound.

Assess the crack width. Hairline: Clean, fill with spackle, sand, prime, paint. Wider: Apply mesh tape and joint compound, sand, prime, paint. Good: Repair complete—done. Bad: Crack reappears—may need pro or structural assessment.

Hairline Wider

You can change your answer later.

Fill hairline crack and paint

Clean the crack. Fill with spackle. Sand flush. Prime and paint to match. Let dry. If the crack reappears, it may be from ongoing movement—call a pro to assess.

Done

Apply mesh tape, joint compound, and paint

Apply mesh tape over the crack. Spread joint compound over the tape, feathering the edges. Let dry. Apply a second coat if needed. Sand smooth. Prime and paint. If the crack reappears, call a pro to assess.

Done

Call a foundation or structural pro

Call a foundation or structural professional if: the crack is stair-step (in brick or block), horizontal, wider than 1/4 inch, growing, or accompanied by sticking doors or windows. Confirm you have assessed the crack type before calling.

Done

Different problem

If the wall looks intact, you may have a different problem—hole, stain, or moisture. See the relevant guide.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why does a wall crack?
Common causes: normal settling, temperature and humidity changes, or minor framing movement. Hairline and vertical cracks are often cosmetic. Stair-step cracks in brick or block, or horizontal cracks, can indicate foundation or structural issues.
Can I fix a wall crack myself?
Yes. Hairline cracks in drywall or plaster can be filled with spackle, sanded, and painted. Wider cracks may need joint compound and mesh tape. If the crack is stair-step, horizontal, or wider than 1/4 inch, call a pro to rule out foundation problems first.
When should I call a pro for a wall crack?
Call a foundation or structural professional if the crack is stair-step (in brick or block), horizontal, wider than 1/4 inch, growing, or accompanied by doors or windows that stick. Fix cosmetic cracks yourself; have structural cracks assessed first.

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