How to Repair Cracks in Tile Grout

Grout cracks are an inevitable part of any tile or natural-stone installation. While proper installation methods can keep these cracks to a minimum, all buildings suffer shifting movement and settling over time, and the natural reaction of concrete is to crack as things move around. Plus, seasonal movement from warmth expansion and cold shrinkage will cause cracks. While hairline cracks can be ignored, larger cracks will need to be repaired for both visual and hygienic reasons.


Remove the cracked grout from the joint. You cannot simply fill the void, as this will not fix the underlying crack and it will continue to grow. Use a handheld grout rake tool to scrape the grout out by hand for small areas, such as a single grout joint.


Use an oscillating tool to remove the grout if the crack is over a large area, such as along five or six tiles or an entire floor. Place the blade against the joint, turn the machine on, hold it with both hands and move it up the joint while it shakes the grout loose through vibration. Vacuum up the debris when you are finished with either method.


Mix up some new grout according to the manufacturer’s directions, or use a premixed grout for ease of use. Scoop some grout out of the container with your grout float and apply it to the now-empty void where the original grout existed. Force it into the joint with the tip of the float, scrape the excess clean and wait 15 to 20 minutes for the grout to set up.


Fill a bucket with water, or use a sink if you are dealing with only a small area. Dampen your sponge, but wring out any excess water. Gently smooth the surface of the joint down and wipe any excess grout from the face of the tile. Allow the grout to dry for a minimum of 72 hours before allowing any additional water to come into contact with it.