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Fix cracked grout: rake out, vacuum, regrout, seal

We'll rake out failed grout, regrout and seal—or switch corners to silicone when planes move.

Troubleshooting · Home maintenance
2–6 hours
What you'll need
  • Grout saw or oscillating tool
  • Matching grout and float
  • Sponge and buckets
  • Penetrating sealer
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Steps

Goal: Tell cosmetic grout cracking from loose tile or plane movement before regrouting.

  • Press tiles and listen for hollow sounds; check inside corners for wrong rigid grout.
  • Good: Tiles are bonded—rake joints and regrout.
  • Bad: Tiles move—stop and fix bonding or subfloor first.

Movement

Goal: Decide if the floor flexes enough to reopen joints.

  • Step on joists near the crack; note if flex transfers to the grout line.
  • Good: Little deflection—regrout after deep removal.
  • Bad: Bounce or squeak—add subfloor screws or call a pro before cosmetic grout.

When to get help

Call a tile professional if:

  • Waterproofing or steam-room membranes may be compromised.
  • Natural stone needs acid-sensitive methods you are not comfortable with.

Verification

  • New grout lines are full, evenly tooled, and sealed after cure.
  • Inside corners use silicone, not new grout only.
  • No new cracks after a week of normal use.

Escalation ladder

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

  1. Test tiles Press for hollow or loose tile.
  2. Rake joints Remove grout to half depth.
  3. Regrout and seal Pack, sponge, cure, seal.
  4. Pro Loose field or failed membrane.

What to capture if you need help

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

  • Joint width and sanded vs unsanded
  • Tile type ceramic vs stone
  • Whether cracks are only in corners

Do tiles feel loose around the crack?

Tap and press.

Yes: Stop—address bond before grout. No: Rake and regrout.

Yes No

You can change your answer later.

Rake and regrout

Remove grout; pack new; seal. Good: Stable joints. Bad: Cracks return—check subfloor.

Done

Tile contractor

Loose tile needs removal and proper bonding—not only grout.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why does grout crack?
House movement, deflection under tile, wrong grout type for joint width, or skipped sealing letting water soften the joint. Corners crack when tile planes move differently.
Can I grout over old grout?
Thin skim coats fail—remove enough depth so new grout locks in. For epoxy, often full removal is required per manufacturer.
When should I call a tile pro?
Call if tiles are loose, cracks return in weeks, or you have natural stone that needs acid-safe methods and sealing.

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