Sanded vs. Unsanded Grout

What Is Grout, Really?

Grout is the cement-based filler that sits between tiles. It locks the installation together, keeps moisture out of the substrate, and gives the finished floor or wall a clean, continuous look. Most homeowners only notice grout when it is dirty or cracking, but it is a structural part of the assembly.

Sanded Grout

Sanded grout contains fine silica sand mixed into the cement. The sand adds bulk, strength, and resistance to shrinking. It is the default choice for most floor tile installations and any joint wider than 1/8 inch.

• Best for: floor tile, large-format tile, shower floors, and joints 1/8 inch to 1/2 inch wide.
• Strength: the sand reduces shrinkage, so wider joints are less likely to crack as the grout cures.
• Cost: generally less expensive than unsanded grout.
• Scratch risk: the abrasive sand particles can scratch soft or polished natural stone such as marble, travertine, limestone, and some slate. A polished stone installation usually calls for unsanded grout or a grout specifically formulated for delicate stone.

Unsanded Grout

Unsanded grout, also called non-sanded grout, is a smooth cement mixture without added sand. It is thinner and easier to work into narrow joints. Because it lacks abrasive grains, it is safer for polished and easily scratched materials.

• Best for: joints 1/8 inch or narrower, vertical surfaces like backsplashes and shower walls, and delicate tile such as glass, polished marble, or honed limestone.
• Finish: produces a smooth, uniform look that complements tight grout lines.
• Shrinkage: without sand to add bulk, unsanded grout can shrink more as it dries. That is why manufacturers recommend it only for narrow joints.
• Scratch risk: minimal. This is the safer choice when the tile surface could be marred by abrasive grout.

Joint Size: The Deciding Factor

The width of the grout joint is the most reliable guide. For joints wider than 1/8 inch, sanded grout is the industry standard. For joints 1/8 inch or less, unsanded grout is usually the right call. Using unsanded grout in a wide joint can lead to shrinkage cracks; using sanded grout in a narrow joint can make it difficult to pack the joint fully and evenly.

Natural Stone and Scratch Risk

Natural stone is the biggest exception to the joint-size rule. Even if a stone floor has wider joints, polished marble, travertine, or limestone can be scratched by the sand in standard grout. In those cases, installers either use unsanded grout with a qualified stone-and-tile setting-materials professional, or select a premium sanded grout that is specifically labeled safe for polished stone. When in doubt, test a small hidden area first.

Quick Reference

When to Call a Pro

Grout selection depends on tile type, joint width, substrate movement, and wet-area exposure. If you are planning a bathroom remodel, kitchen backsplash, or natural stone floor in the Columbus area, a tile contractor can specify the right grout and movement joints so the installation lasts.