What to Do About Cracked Grout in Shower
Learn to diagnose, repair, and prevent cracked grout in a shower with a step-by-step approach, safety tips, and maintenance guidance from Grout Maintenance.
This guide helps you fix cracked grout in the shower by assessing damage, choosing a repair method (regrouting, epoxy grout, or sealing), and completing a safe, durable repair. You will need basic tools, replacement grout, and a plan for cleaning, removal, and sealing to prevent future cracks. The steps emphasize safety, moisture control, and proper curing to ensure a long-lasting fix.
Causes of Cracked Grout in Showers
If you are wondering what to do about cracked grout in shower, the cause is often moisture and movement that compromise tile installation. According to Grout Maintenance, moisture intrusion can occur when grout is too soft, too hard, or not properly mixed, leading to small fissures that expand over time. Temperature fluctuations, high humidity, and improper substrate prep are common culprits. Substrate movement from settling or plumbing shifts can also create stress on the grout joints. When cracks appear, water can seep behind the grout, feeding mold growth and even damaging the substrate or backer board if left unaddressed. Early intervention matters because it limits water exposure and reduces the likelihood of expensive repairs later.
Assessing the Extent of Damage
Begin by inspecting all grout lines around the shower, not just the visible cracks. Look for hairline cracks, widening gaps, or hollow-sounding joints when tapped with a screwdriver handle. Use a bright flashlight to check for moisture behind the grout and any signs of mold or mildew on the tile edges. If cracks are deep or the grout crumbles easily with light pressure, you are facing a more serious repair. Record the location, width, and whether cracks appear in one area or multiple walls. Shallow, single-line cracks may be addressed with regrouting, while widespread cracking often requires removing and replacing grout across larger areas, or even retiling if substrate damage is present.
Repair Options: Regrouting vs. Full Tile Replacement
You have several routes when grout cracks appear: (1) regrout the affected joints with cementitious grout; (2) use epoxy grout for a more durable, water-resistant seal; or (3) reseal and patch with silicone at movement joints while leaving intact tile. Regrouting is quicker and cheaper but may not last if underlying substrate issues persist. Epoxy grout resists cracking and stains but can be harder to apply and remove. In cases of severe cracking or substrate damage, replacing affected tiles or retiling the shower may be necessary. The right choice depends on crack width, area, and moisture exposure, plus your comfort level with grout removal.
Cleaning and Prep Before Repair
Before removing or applying grout, ensure the shower is dry and well-ventilated. Remove soap scum, mineral deposits, and mold with a tile-safe cleaner, and rinse thoroughly. Allow the area to dry completely—24 hours is a typical minimum for thorough moisture evacuation, especially in non-ventilated spaces. Tape off nearby surfaces to protect them from dust and cleaner residues. Dry joints allow the new grout to adhere properly and cure evenly, reducing the risk of future cracking.
How to Remove Damaged Grout
Safety first: wear eye protection and a dust mask. Use a grout removal tool or oscillating multi-tool to remove cracked grout along the joints; avoid chipping tile edges. Stop when you reach solid, sound grout and a smooth surface. Vacuum out dust and debris, then wipe the joints with a damp rag to remove fine particles. Let the joints dry completely before applying new grout. Removing only the damaged portion minimizes work and preserves intact grout elsewhere.
Regrouting: Step-by-Step Overview
Apply your chosen grout with a float, pressing it firmly into the joints to fill gaps fully. Wipe away excess grout with a damp sponge, then shape the joints for a neat finish. After initial set (as per product instructions), cure time typically ranges from 24 to 72 hours; avoid moisture during this period. Seal cementitious grout after curing with a compatible penetrating sealer, typically requiring another 24 hours to cure. Epoxy grout set times differ; follow the manufacturer's guidance for mixing, application, and curing.
Sealing and Maintenance to Prevent Cracks
Once grout has cured, apply a grout sealer to reduce water penetration, ideally within 48 hours of final curing. For showers, reseal every 6 to 12 months or as recommended by the sealer manufacturer. Regular cleaning with pH-neutral cleaners helps maintain the grout's integrity and color. Address any new hairline cracks promptly to avoid compounded moisture damage. Routine upkeep includes inspecting corners and movement joints and reworking those areas if movement occurs.
Safety, Timing, and When to Call a Pro
Repairing shower grout can be a DIY-friendly project, but if you encounter recurring cracks, mold behind tiles, or suspected substrate damage, it is wise to consult a licensed tile pro. Persistent moisture, efflorescence, or discoloration may indicate hidden issues that require professional assessment. Always work in a well-ventilated area, wear protective equipment, and follow manufacturer curing times to avoid compromising the repair.
Authoritative Sources and When to Call a Pro
For additional guidance, consult reputable sources such as university extension publications or government home improvement resources. If you are unsure about substrate damage or proper grout choice, a professional inspection can save time and prevent costly mistakes.
Tools & Materials
- Grout removal tool or oscillating multi-tool(Used to remove damaged grout along the joints)
- Utility knife or dental pick(Enables precise clearing in stubborn spots)
- Grout float(For pressing new grout into joints)
- Replacement grout (cementitious or epoxy)(Choose based on crack severity and moisture exposure)
- Sponge, clean bucket, and water(For cleaning and finishing)
- Tile-safe cleaner(For initial cleaning and mold removal)
- Sealer suitable for grout type(Penetrating sealer for cementitious grout or epoxy grout sealer)
- Painter's tape or masking tape(Protect adjacent surfaces)
Steps
Estimated time: 2-6 hours active work; 24-72 hours curing time depending on grout type
- 1
Assess and prepare
Survey the area and gather your tools. Identify the cracks and plan your approach, ensuring good ventilation and a dry work area before starting.
Tip: Safety first: wear eye protection and a mask to avoid dust inhalation. - 2
Remove damaged grout
Carefully remove cracked grout along the joints to the depth of sound grout, taking care not to chip tile edges. Vacuum out dust after removal.
Tip: Work in small sections to maintain control and prevent accidental tile damage. - 3
Clean and dry joints
Thoroughly clean joints to remove soap scum and mildew; allow joints to dry completely.
Tip: Moisture is the enemy of good adhesion—dry joints yield better results. - 4
Mix and apply grout
Prepare grout to manufacturer-consistent slurry and press into joints with a float, ensuring full depth filling.
Tip: Avoid over-watering grout; it can weaken adhesion and shrink during cure. - 5
Wipe and shape joints
Wipe excess grout from tile faces with a damp sponge and shape joints for a smooth, uniform finish.
Tip: Wipe in a consistent direction to avoid gouges in the grout. - 6
Allow curing and seal
Let grout cure per product instructions; seal cementitious grout after cure and keep area dry.
Tip: Do not expose to water or humidity during the initial cure period. - 7
Final checks and maintenance
Inspect grout lines after curing; apply sealer if required and set a maintenance routine to prevent future cracks.
Tip: Schedule resealing every 6-12 months for showers.
Got Questions?
Can cracked grout be repaired without removing all grout?
In some cases, small cracks can be filled with epoxy or cementitious grout without removing all grout, but deep or widespread cracking may require removal and regrouting.
Some cracks can be filled, but if you see widespread damage, you may need to regrout.
What grout type is best for showers?
Epoxy grout is highly resistant to moisture and stains, making it a good choice for showers; cementitious grout with a quality sealer can also perform well.
Epoxy grout resists moisture and staining; cementitious grout with sealing works too.
How long does grout take to cure?
Cure times vary by product, but most cementitious grouts cure within 24-72 hours; epoxy grout cures faster but requires precise mixing.
Most grouts cure in 24 to 72 hours; epoxy grout cures per manufacturer instructions.
Should I call a professional if cracks recur?
Yes. Recurring cracks may indicate substrate movement or hidden moisture issues that require professional assessment.
If cracks come back, it's time to get a pro to assess the underlying cause.
Can I seal grout immediately after installation?
Seal cementitious grout after it has cured according to product instructions; sealing too early can trap moisture and cause issues.
Seal only after the grout has cured as directed.
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The Essentials
- Inspect cracks early and choose the right repair method
- Dry joints ensure better grout adhesion
- Seal grout after curing to protect against moisture
- Monitor for new cracks and address promptly
