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Repairing Cracks in Tile Grout 

Properly installed tile and grout should allow for the normal expansion and contraction of tile flooring; however, even minor earthquake tremors may cause the grout to begin to crack and crumble. Once the grout cracks for any reason, it’s time to repair broken grout before there is any damage to the surrounding tiles. While grout may crack from wear and tear, an uneven or weak subfloor may be causing the problem. If you need to repair grout numerous times on any one floor, ask an engineer to look into the underlying cause of the problem.

How to Repair Cracks in Tile Grout

1. Measure the width of the grout lines on your tile floor. If the lines are less than one-eighth of an inch, you need unsanded, epoxy or acrylic latex grout. Grout lines wider than one-eighth of an inch need sanded grout. The exception to this is marble tile floors. Sanded grout scratches the surface, so use unsanded, epoxy or acrylic latex on them.
2. Remove a small piece of the broken grout and take it with you to a tile or home improvement store. Match new grout to the sample. You might be able to use more or less water as you mix the grout to get an exact match on the grout shade, but doing so may affect the quality of the grout’s texture and its structural integrity.
3. Mix 1 part white vinegar with 1 part water. Clean the area of broken grout with the vinegar mixture.
4. Cut out the damaged grout with a grout saw. Insert the blade of the saw, which looks like a screwdriver or round handle with a saw on the end, into the joint with the damaged grout. Move the saw back and forth along the joint to cut out the grout. If the grout is particularly difficult to remove, apply more pressure to the grout saw as you move the saw along the joint. Take care not to damage the tiles.
5. Wipe a damp paper towel over the grout line to clean it out. Remove any excess water puddled in the grout lines. Leave the sides of the tile slightly damp to help the grout bind to the tiles.
6. Follow package directions for adding the correct amount of water to the grout you selected. Pre-mixed grout has the proper proportions of sand, if necessary, and Portland cement. Add water to the grout in a disposable mixing container. The grout should hold together in a ball when it's the proper consistency. Push the grout into the joint with a grout float. Smooth the joint with the rounded end of a craft stick.
7. Wipe the surface of the surrounding tiles with a clean, damp sponge. Rinse the sponge frequently to avoid smearing grout onto adjoining tiles. Allow the grout to dry following manufacturer’s recommendations. Temperature and humidity may affect drying times.
8. Clean the surface of the surrounding tiles completely with a soft cloth. If the cloth doesn't remove the haze, mix 1 part white vinegar with 1 part water. Wipe this mixture over the tile with a clean sponge. Wipe it dry with the cloth.
9. Apply a grout sealer with a small paintbrush following manufacturer’s directions. Allow the grout sealer to dry.

Tip: Seal all the grout in the room as you finish the project to add an extra layer of protection for the grouted joints.

If you see small, hairline cracks in the grout, mix up a small amount of unsanded grout and apply it directly into the damaged joint using a clean finger. Wipe off any excess from the surrounding tiles and allow the grout to dry.

But when in doubt, it’s best to leave it to the professionals. If you’re in Texas or in the surrounding area, don’t forget to call Dust Commander at 903-357-4640. Our operators are standing by, ready to answer any questions you may have. Contact us today!