How to Repair Cracked Grout: A Complete Step-by-Step Guide
Cracked grout is one of the most common problems homeowners face, especially in bathrooms, kitchens, and other tiled areas. Not only does cracked grout look bad, but it also allows moisture to seep behind tiles — leading to loose tiles, mold growth, and costly repairs. https://groutking.ae/how-to-repair-cracked-grout/
The good news? Repairing cracked grout can be simple when done correctly. This guide explains why grout cracks, how to fix it, and when to call a professional.
Why Does Grout Crack?
Before repairing grout, it’s important to understand what caused the cracking. Common reasons include:
1. Poor Installation
If grout was mixed incorrectly or tiles were not set properly, grout can weaken and crack.
2. Excess Moisture
Bathrooms and kitchens experience constant moisture. Over time, this weakens grout, especially unsealed grout.
3. Structural Movement
Homes naturally shift. Even slight movement can cause grout lines to crack.
4. Heavy Use
High-traffic areas or frequently used showers wear down faster.
Types of Cracked Grout
Understanding the type of crack helps decide the right repair method:
- Hairline cracks – Small, shallow cracks that usually only need surface repair.
- Deep cracks – Larger cracks that may require removing old grout.
- Missing grout – Entire sections need to be replaced.
- Cracks in corners – Should be replaced with silicone caulk for flexibility.
How to Repair Cracked Grout (Step-by-Step)
Tools & Materials Needed
- Grout saw or multi-tool
- Replacement grout (sand or unsanded matching the existing)
- Grout float
- Vacuum or brush
- Sponge
- Caulk (for corners)
- Sealer (optional but recommended)
Step 1: Inspect the Damage
Examine the grout lines carefully. Identify whether the crack is:
- Only on the surface
- Deep and crumbling
- Spread across multiple areas
This helps determine if you need a partial fix or complete regrouting.
Step 2: Remove the Old Cracked Grout
For deep or broken grout:
- Use a grout saw or oscillating tool.
- Remove the damaged grout carefully without scratching the tiles.
- Clean out all loose dust using a brush or vacuum.
If it’s only a hairline crack, you can skip removal and patch directly.
Step 3: Mix the New Grout
- Follow manufacturer instructions.
- Make a smooth, peanut-butter-like consistency.
- Prepare only the amount you’ll use within 20 minutes.
Step 4: Apply the New Grout
- Spread grout diagonally across the joints using a grout float.
- Press firmly to fill gaps completely.
- Remove excess grout from the tile surface.
Step 5: Clean the Tiles
After 10–15 minutes:
- Lightly wipe the tiles with a damp sponge.
- Rinse often to avoid grout haze.
- Do not press too hard or you may remove grout from the joints.
Step 6: Let the Grout Cure
Allow grout to dry for:
- 24–48 hours for light use
- 72 hours before heavy water exposure (showers, cleaning)
Step 7: Seal the Grout (Optional but Highly Recommended)
Applying a sealer helps:
- Protect against moisture
- Reduce mold and mildew
- Extend grout lifespan
Reapply sealant every 6–12 months for best results.
Repairing Cracked Grout in Corners
Grout is not the right material for corners because tiles expand and contract.
Instead:
- Remove cracked grout
- Replace with 100% silicone bathroom caulk
- Smooth the bead with a wet finger or tool
This prevents future cracking.
When Should You Call a Professional?
DIY grout repair works for small cracks. But professional help is needed when:
- Cracks keep coming back
- Multiple tiles are loose
- Water damage is visible
- Mold is growing
- You want perfect color matching and finishing
A professional grout technician ensures long-lasting results with the right tools, materials, and sealing.
Final Tips to Prevent Future Grout Cracks
- Seal grout regularly
- Fix loose tiles immediately
- Use flexible caulk in corners
- Avoid harsh cleaners
- Maintain proper ventilation in bathrooms
