How to repair cracking grout

Close-up of a person's hands using a specialized grout removal tool to carefully scrape away old, cracked grout from between white ceramic tiles.
Photo: Vladimir Srajber / Pexels
Close-up of a person using a rubber grout float to spread fresh gray grout into the joints of newly installed white subway tiles on a wall.
Photo: Curtis Adams / Pexels

Understanding Grout Cracks

Grout may crack for a variety of reasons, which could include factors related to subfloor movement, installation conditions, or settling over time.

Cracks in grout lines may allow moisture to reach the area beneath the surface, which could potentially lead to further issues with the tile assembly.

Preparing for Grout Repair

A common first step in addressing cracked grout involves removing the damaged material from the grout lines.

Tools such as a grout saw or a utility knife are often used to scrape out old or failing grout from between tiles.

After removing old grout, cleaning the area thoroughly is generally recommended to help new material adhere properly. Removing dust, debris, and loose material from the joint is typically advised.

Applying New Grout

New grout is generally mixed according to the product manufacturer's instructions to achieve the intended consistency.

The grout is commonly worked into clean grout lines using a rubber float, with care taken to fill gaps as completely as possible.

Excess grout is typically wiped away with a damp sponge shortly after application to help avoid residue or hazing on the tile surface.

Curing and Sealing Repaired Grout

After new grout is applied, allowing it to cure for the period specified by the product manufacturer is generally recommended.

Adequate curing time is intended to help the grout develop strength before the area is exposed to regular use or moisture.

Once cured, a grout sealer is sometimes applied with the goal of helping protect the grout from moisture and stains.

Key takeaways

  • Consider investigating the possible cause of grout cracks to help reduce the likelihood of future occurrences.
  • Removing old grout and cleaning the area before applying new material is a commonly recommended step for better adhesion.
  • Following manufacturer guidance on mixing, application, curing, and sealing is generally considered important for grout repair durability.

Related tools

Estimate materials with our free tile materials calculator on TileMaterials.

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