To fix cracked or missing grout, rake out the failed grout, clean the joint, and refill with fresh grout that matches the original type and color. Cracking usually points to movement or a joint that was mixed too dry, so choosing the right grout for the joint width and location prevents it from happening again.

Why grout cracks or falls out

• Movement in the substrate or between tiles flexes rigid grout until it cracks.
• Grout mixed too dry or too wet cures weak and crumbly.
• Wrong grout for the joint width, such as unsanded grout in a wide joint.
• Missing expansion joints where the tile field meets walls or changes plane.

How to regrout, step by step

1. Rake out the cracked or loose grout with a grout saw or removal tool.
2. Vacuum the joint and wipe it clean so the new grout bonds.
3. Mix fresh grout to the right consistency for the joint width.
4. Pack it fully into the joint and tool it smooth.
5. Clean the haze, let it cure, then seal cement grout.

Choosing the right replacement grout

Match the new grout to the joint so the repair lasts. Narrow joints (generally under 1/8 inch) call for an unsanded grout, while wider joints need a sanded formula. Matching the original color keeps the repair invisible, or you can recolor the whole area for a uniform look.

When cracking signals a bigger issue

Grout that keeps cracking in the same spot can mean the substrate is moving or an expansion joint is missing. In that case, fixing only the grout is a temporary patch. Address the movement, or use a flexible, polymer-modified grout that better tolerates it.

SGM products

For repairs, a Grout Kit has what you need. Narrow joints do best with Dry-Set Grout, and for movement-prone areas, Security Polymer Grout adds flexibility and strength.