How to Grout Floor Tile: Application, Joints, and Sealing

Grouting is the last structural step in a tile installation and the one that most DIYers rush. Moving too fast — mixing grout too dry, applying before thinset is cured, or washing too aggressively — results in cracked joints, streaky haze, and grout that stains within weeks.

Grouting is the last structural step in a tile installation and the one that most DIYers rush. Moving too fast — mixing grout too dry, applying before thinset is cured, or washing too aggressively — results in cracked joints, streaky haze, and grout that stains within weeks. Done correctly, a grout job on floor tile lasts a decade or more before it needs attention.

This guide covers the complete process from selecting the right grout through sealing the finished floor.

What You Need

• Laticrete floor grout sanded — professional-grade polymer-modified grout for floors
• Rubber grout float — the correct tool for packing grout into joints and scraping excess
• Grout sponge — large, dense sponge for washing without pulling grout from joints
• Penetrating grout sealer — soaks in to protect without changing the grout appearance
• Grout haze remover — removes dried grout film from tile surface
• Margin trowel — for scooping, mixing, and loading grout onto the float

Choosing Grout: Sanded vs Unsanded and Color Selection

For most floor tile with joints of 3/16 inch or wider, use sanded grout. It is available in a wide range of colors and is the standard product for floor installations.

Color selection tips:

• Grout color affects how noticeable the joint lines are. A grout color that closely matches the tile body makes the floor look more continuous; high-contrast grout makes the pattern more graphic.
• Grout color chips in the store look much smaller than the actual floor. If possible, test a small section or request a sample.
• Lighter grout colors show staining more readily and require more diligent sealing and maintenance.
• Most manufacturers sell color-matched grout and tile as a system — ask at the tile counter.

Mixing Grout

Consistent mixing is critical. Improperly mixed grout crumbles, cracks, or cures with color variation.

1. Pour the dry grout into a clean bucket first.
2. Add water gradually — most sanded grouts use approximately 1 quart of water per 5 pounds of dry grout, but follow the manufacturer’s ratio exactly.
3. Mix with a margin trowel or a low-speed drill with a paddle attachment. Avoid high speed, which traps air bubbles.
4. The correct consistency is peanut butter — thick enough to hold a shape when you press it, but workable. It should not be soupy or crumbly.
5. Let the mix slake for 10 minutes with no stirring, then mix once more briefly. Slaking allows the polymers to fully hydrate.
6. Mix only as much as you can use in 30 minutes. Grout stiffens quickly as water evaporates.

Applying Grout with the Float: Diagonal Technique

Work in sections of 10 to 15 square feet at a time.

1. Remove all tile spacers from the joints before grouting.
2. Dampen the tile surface lightly with a sponge if the tile is very porous or if conditions are hot and dry. This slows the grout from drying too fast.
3. Drop a workable amount of grout onto the tile with the margin trowel.
4. Hold the float at 45 degrees and work it diagonally across the joint lines. The diagonal angle pushes grout into the joint from both sides simultaneously.
5. Apply firm downward pressure as you move across the tile.
6. After packing a section, tilt the float to about 75 to 80 degrees and make one or two diagonal passes to scrape off excess grout from the tile surface. Do not scrape parallel to joints — this pulls grout out.

Cleaning Grout Haze

Cleaning in two passes is the correct technique. Cleaning too aggressively in the first pass pulls grout from the joints.

First pass — 15 to 20 minutes after applying:

1. Wring a sponge nearly dry — almost no water should remain. A wet sponge dissolves the grout in the joints.
2. Wipe the tile surface in a circular motion. The goal is removing the bulk of the grout from the tile face, not scrubbing.
3. Rinse the sponge in clean water, wring nearly dry, and repeat.
4. Change the wash water frequently. Dirty water smears haze back onto tile.

Second pass — 2 to 4 hours after applying:

1. Buff the remaining light haze with a dry cheesecloth or microfiber cloth.
2. If haze remains after 24 hours, apply a grout haze remover per the product instructions.

Sealing the Grout

Allow grout to cure fully — at least 72 hours, or up to 7 days for high-moisture areas — before sealing.

1. Make sure the floor is clean and completely dry.
2. Apply penetrating sealer to the grout lines with a brush applicator, a foam paintbrush, or a squeeze bottle with a narrow tip. Avoid getting sealer on polished stone tile — it can alter the finish.
3. Let the sealer penetrate for 5 to 10 minutes.
4. Wipe away any excess sealer on the tile surface before it dries.
5. Apply a second coat after the first has dried (typically 30 minutes) for better protection.
6. Do not mop the floor or let it get wet for 24 hours after sealing.

Related Reading

• How to Tile a Bathroom Floor
• How to Grout Tile
• How to Seal Grout
• How to Fix a Floor Tile That Is Loose — reattach a hollow tile before regrouting
• How to Repair Grout