Unsanded grout can give tile work a smooth, clean finish, but it’s less forgiving than it looks. Mix it too wet, leave thinset in the joints, or scrub it before it has set, and you can end up with weak grout, uneven color, or a stubborn haze. The good news? With the right joint size, a careful mix, and a few well-timed cleaning steps, you can install it neatly yourself.
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What Unsanded Grout Is—and When to Use It
Unsanded grout is a cement-based grout made without the gritty sand found in many standard grout mixes. That smooth texture makes it easier to press into narrow joints and less likely to scratch delicate tile surfaces during installation.
It’s commonly used for grout joints about 1/8 inch wide or narrower, but the exact limit depends on the product. Always check the package: some unsanded grouts are designed for slightly different joint widths, and the manufacturer’s instructions take priority.
It can be a good choice for polished stone, some glass tile, and other surfaces that may scratch. But don’t assume every delicate tile needs unsanded grout. Some glass or stone manufacturers recommend a particular grout type, so check their guidance before you start.
| Feature | Unsanded grout | Sanded grout |
|---|---|---|
| Typical use | Narrow joints, often around 1/8 inch or less | Wider joints, within the product’s stated range |
| Texture | Smooth and fine | Gritty, with sand in the mix |
| Main advantage | Works into narrow joints and is less abrasive | Better suited to wider joints where shrinkage can be a concern |
| Main caution | Can shrink or crack if used in joints that are too wide | May scratch some delicate tile surfaces |
Using unsanded grout in a joint that’s too wide can lead to shrinkage or cracking as it dries. Choosing the right grout is part of the installation, not just a product preference.
Gather Your Tools and Prepare the Tile
Have your materials ready before mixing. Cement grout starts its working time once water is added, so stopping halfway to hunt for a clean sponge is a recipe for a rushed finish.
- Unsanded grout that’s suitable for your tile and joint width
- A clean bucket and a grout mixing tool or margin trowel
- A rubber grout float
- Two clean buckets of water and a grout sponge
- Soft, dry cloths for removing the final haze
- Gloves, eye protection, and any safety gear listed on the product label
Before grouting, let the tile adhesive or thinset cure for the time stated by its manufacturer. Grouting too soon can trap moisture or disturb tiles that haven’t set firmly.
Next, inspect the joints. Remove spacers, loose debris, and any thinset that has squeezed up between the tiles. Aim for joints that are clean and evenly open; thinset should not block the grout from filling the joint to a consistent depth. A plastic scraper or a tool recommended for your tile can help. Work carefully so you don’t chip tile edges.
Vacuum or wipe away the debris, and make sure the surface is ready for grout. If you’re working with porous or unglazed tile, check whether it needs a compatible sealer or special preparation first. Some grout can stain certain tile surfaces.
Mix Unsanded Grout to the Right Consistency
Follow the water-to-grout ratio on the package. This matters more than it may seem: too much water can weaken cement grout and contribute to color variation, while a mix that’s too stiff can be difficult to press completely into the joints.
Mix a Small Batch First
Measure the water rather than pouring by guesswork, then add the grout powder as directed. Mix slowly until the grout is smooth and holds its shape without looking runny. If you’re new to grouting, make a smaller batch so you can work at a comfortable pace.
Many cement-based grouts call for a short resting period, often called slaking, before you mix them again. Other products may give different directions. Follow the label for the correct wait time and remix instructions. If the directions say to remix without adding more water, don’t thin the grout just because it seems to firm up.
Dry grout powder can irritate your eyes and lungs. Mix in a well-ventilated area, avoid breathing dust, and follow the safety instructions on the package or safety data sheet. Don’t dry-sweep spilled powder.
How to Install Unsanded Grout
1. Spread Grout Across the Tile
Pick up a manageable amount of grout with the rubber float. Hold the float at an angle and press the grout firmly across the tile, working diagonally to the joints. The diagonal motion helps fill the gaps rather than dragging grout back out of them.
Work in small sections you can clean before the grout becomes too firm. For a first-time DIY job, a few square feet at a time is often easier to manage than covering a whole room at once. The right section size depends on your pace, room temperature, and the grout’s working time.
2. Pack the Joints Fully
Make several passes across the joints from different directions. Press the float down so the grout reaches the bottom of each open joint and doesn’t leave air pockets. If a joint looks hollow or low, add more grout and pack it in while the mixture is still workable.
Once the joints are filled, hold the float at a steeper angle and sweep diagonally across the tile to remove excess grout. Try not to dig into the joints as you do this.
3. Let the Grout Firm Up, Then Sponge the Tile
Wait until the grout has begun to firm before cleaning. The right timing varies with the product and conditions, so use the label and watch how the grout behaves. If you wipe too soon, you may pull grout out of the joints. Wait too long, and the residue can become much harder to remove.
Dampen a clean grout sponge and wring it out thoroughly. It should be moist, not dripping. Wipe gently across the tile in a diagonal motion, turning the sponge to a clean side often. Rinse it frequently in clean water, and change the water when it becomes cloudy.
Use light pressure. Pressing hard or repeatedly scrubbing the same spot can wash the joints, leave them uneven, or change their color. You’re cleaning grout off the tile surface, not rinsing the joints out.
4. Remove the Haze
After the grout has firmed further, a light cloudy film may remain on the tile. Buff it away with a clean, dry cloth when the product instructions say it’s time. If haze remains, don’t immediately reach for a strong acid cleaner. Some cleaners can damage grout, tile, or stone. Use only a cleaner approved for your materials, and follow its directions.
Curing, Sealing, and Protecting the Grout
Fresh grout needs time to cure. Keep the surface protected from foot traffic, water, spills, and harsh cleaning for the period stated on the grout package. Temperature and humidity can affect drying, so avoid assuming that every grout is ready on the same schedule.
Some cement-based grouts benefit from a compatible sealer, while other products may not need one or may have different care instructions. Check the manufacturer’s directions before sealing. If sealing is recommended, wait until the grout has cured for the specified period, and apply the sealer without leaving excess on the tile.
Grout itself is not a waterproofing system. In a shower or other wet area, the waterproofing comes from the correctly installed membrane and details behind or beneath the tile. Grout helps fill joints, but it shouldn’t be treated as a replacement for proper waterproofing.
Also, don’t fill movement joints, such as changes of plane where a tiled wall meets a floor or another wall, with rigid grout. Those areas can move slightly. Use the flexible sealant or other detail specified for your installation instead.
Common Mistakes to Avoid
- Using unsanded grout in joints that are too wide: It may shrink or crack. Match the grout to the joint width listed on the package.
- Adding extra water: A soupy mix is harder to control and may weaken the finished grout or lead to uneven color.
- Leaving thinset in the joints: Blocked joints can prevent grout from filling evenly and may leave shallow, inconsistent lines.
- Cleaning with a dripping sponge: Too much water can wash grout from the joints. Wring the sponge out well and rinse it often.
- Rushing the cleanup: Wiping too early pulls grout out; waiting too long makes residue harder to remove. Work in small sections and pay attention to the grout’s set.
- Grouting movement joints: Corners and other movement areas generally need a flexible sealant, not rigid grout.
- Ignoring tile-specific instructions: Natural stone, glass, and porous tile may need special preparation or a specific grout.
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- 10 common shower tile grout cracking causes their solutions
Frequently Asked Questions
How wide can a joint be for unsanded grout?
Many unsanded grouts are intended for joints about 1/8 inch wide or narrower, but product limits vary. Check the package and use a grout made for your actual joint width.
Can I use unsanded grout on a shower wall?
Often, yes, if the tile, joint width, and grout product are suitable for it. Follow the grout and tile manufacturers’ instructions, allow the grout to cure as directed, and make sure the shower has a proper waterproofing system.
Should I seal unsanded grout?
It depends on the product. Some cement-based grouts recommend a compatible sealer; others have different requirements. Check the label and wait the stated cure time before sealing.
Why does my grout look uneven in color?
Too much mixing water, excess water during cleanup, inconsistent mixing, or different drying conditions can all affect color. Follow the water ratio, mix consistently, use a well-wrung sponge, and let the grout cure as directed.
Conclusion
To install unsanded grout successfully, start with clean joints and a grout that matches their width and your tile. Mix only as directed, pack the joints fully, and clean in small sections with a barely damp sponge. Give the grout time to cure, follow the product’s sealing advice, and use flexible sealant where the tiled surface needs room to move.
