How to Repair Cracked Grout on Backsplash

Repairing cracked grout on a backsplash is a common DIY home repair that can restore the look of your kitchen or bathroom. With some simple tools and materials, you can fill cracked grout lines and make them look new again. Here is a step-by-step guide on how to repair cracked grout on a backsplash.

What You’ll Need

  • Grout removal tool or grout saw – to remove loose grout
  • Grout float or grout sponge
  • Grout sealer
  • Caulk gun
  • Grout – sanded grout for wider joints, unsanded for narrow joints
  • Grout sealing product
  • Mixing bucket, putty knife
  • Grout coloring kit (optional)
  • Dust mask
  • Gloves and eye protection

Cleaning Out The Cracked Grout

Before regrouting, you need to fully clean out any loose or crumbling grout. This ensures the new grout will bond properly.

Step 1: Remove any Sealer

If the existing grout has a sealer, you’ll need to remove it so the new grout can bond. Use a grout sealer remover product and follow the directions.

Step 2: Clear Out Loose Grout

Use a grout removal tool or grout saw to dig out any loose, cracking grout. Remove it down to a depth of at least 1/8 inch. Clean out any grout debris as you go.

Step 3: Clean with Vinegar

Wipe the grout lines with white vinegar to remove any remaining debris and grease. This etches the surface so new grout can adhere. Rinse thoroughly.

Step 4: Dry Completely

Allow the grout lines to dry fully before regrouting. Use a hair dryer on low setting if needed.

Mixing and Applying New Grout

With the joints clean and ready, it’s time to mix and apply fresh grout.

Step 1: Prepare the Work Area

Cover any walls, countertops or floors around the backsplash area with rosin paper or drop cloths. This protects surfaces from grout smears or drips.

Step 2: Mix the Grout

Prepare grout mix per package instructions. Only mix up as much as can be applied within 30 minutes.

Step 3: Apply Grout to Joints

Use the grout float or a stiff grout sponge to force grout into the seams. Hold at a 45° angle and firmly pack it in. Completely fill joints.

Step 4: Let Grout Firm Up

Allow grout to firm up in the joints, waiting about 10-15 minutes. Don’t let it dry completely.

Step 5: Clean Excess Grout

Use a lightly damp grout sponge in a circular motion to smooth joints and clean off excess grout. Rinse sponge frequently.

Step 6: Final Cleaning

Once the grout has cured, about 24 hours, do a final cleaning to remove any remaining haze or film. Use a grout sealing product.

Curing and Sealing the Grout

Allowing the grout to cure fully and sealing it properly will help prevent cracks from forming again.

Allow at Least 72 Hours to Cure

Don’t get the grout wet for at least 72 hours as it cures. Avoid cleaning or wiping the area during this time.

Apply a Grout Sealer

Once fully cured, apply a penetrating grout sealer as a protective barrier. This prevents stains and damage. Re-apply yearly.

Consider Using Caulk in Corners

In corner joints or wide gaps, fill with silicone caulk after grouting for flexible waterproofing. Smooth with a fingertip.

Grout Repair Tips

  • Match new grout color to old as closely as possible for a uniform look
  • Use unsanded grout for joints 1/8 inch or less, sanded for wider gaps
  • Change mixing water amounts to adjust grout consistency
  • Use a grout coloring kit to tint if needed for color matching
  • Grout can crack again if a bad batch or mix ratio – re-do it

With some basic tools and materials, repairing cracked grout on a backsplash is a doable DIY project. Just take time to fully clean out old grout, apply new properly, and cure and seal it. This will restore the look of cracked grout lines.

Frequently Asked Questions About Repairing Cracked Grout

What is the easiest way to remove old grout?

The easiest way is to use a grout saw or rotary tool with a grout removal bit. This allows you to quickly and easily dig out cracked, loose grout.

How do I know if I need sanded or unsanded grout?

Use sanded grout for joints wider than 1/8 inch. It has fine sand particles that help fill gaps. Unsanded is for narrow grout lines 1/8 inch or less.

How long does grout take to dry before sealing?

Grout needs about 72 hours to fully cure and dry before applying a protective sealer. Don’t get the grout wet during this time.

Should I use caulk or grout in corners and wide gaps?

Caulk is better for corners and wide joints. It allows for expansion and contraction and won’t crack. Apply after grouting the remaining joints.

What is the best grout sealer to use?

Penetrating sealers that soak into the grout work best. Topical coatings can peel off over time. Look for a sealer suitable for grout and natural stone.


Repairing cracked and damaged grout on a backsplash or other tiled surface is a relatively easy DIY project. Following the proper steps of cleaning out old grout, applying fresh grout, and curing and sealing it properly will help ensure your repaired grout lines look great and stay crack-free. Paying attention to details like completely filling the joints, smoothing, and cleaning excess grout will lead to a successful repair.