Sanded vs Unsanded Grout: Which One You Need (2024)

TL;DR: Use sanded grout for joints wider than 1/8 inch (floor tile, shower floors, most 12x12 tiles) because the sand adds strength and resists shrinking. Use unsanded grout for joints 1/8 inch or narrower, and always on polished stone or glass tile, since sand grains will scratch soft surfaces. When in doubt, check the tile manufacturer's spec sheet before you mix a bag.

_Last reviewed: July 2026 · 6 min read_

You're standing in the tile aisle with two bags of grout that look identical, and the wrong pick means a cracked joint or a scratched countertop six months from now. The difference isn't marketing. It's about joint width and what your tile surface can handle.

Okoniq Property Hub helps you log which grout and joint width you used on each tile job, so the next repair matches the original instead of guessing.

What's the actual difference between sanded and unsanded grout?

Sanded grout has fine silica sand mixed into the cement-based formula. Unsanded grout is the same base without the sand. The sand does two things: it bulks up wider joints so the grout doesn't shrink and crack as it cures, and it adds compressive strength for high-traffic floors.

Unsanded grout is smoother and stickier, which is why it clings well to vertical surfaces and thin joints without sliding down. It's also gentler on tile that scratches easily. A 50-pound bag of sanded grout typically costs $15 to $25, while unsanded runs slightly higher per pound because it needs more binder to hold its shape without the filler.

Which one do you actually need for your joint width?

The 1/8-inch rule decides it. Joints wider than 1/8 inch need sanded grout. Joints 1/8 inch or narrower need unsanded. This isn't a suggestion from a salesperson, it's physics: without sand, wide joints shrink unevenly as they dry and hairline cracks form within the first year.

Most floor tile (12x12, 18x18, plank tile) is set with 3/16-inch to 1/2-inch joints, so sanded is the default there. Subway tile, mosaic sheets, and glass tile backsplashes are usually set at 1/16 inch to 1/8 inch, which calls for unsanded. If you're regrouting an old shower and aren't sure of the original width, measure with a ruler at three spots before buying anything.

| Sanded Grout | Unsanded Grout | |---|---| | Joints wider than 1/8" | Joints 1/8" or narrower | | Floor tile, showers, decks | Wall tile, backsplashes, vertical joints | | Higher shrink resistance | Smoother, stickier for thin lines | | Can scratch polished stone/glass | Safe for polished surfaces |

Can sanded grout scratch or damage your tile?

Yes, on soft or polished surfaces. Polished marble, limestone, and glass tile are soft enough that the silica sand grains can leave fine scratch marks during application, especially if you press hard with a rubber float. Manufacturers like Custom Building Products and Mapei explicitly recommend unsanded grout for any polished natural stone regardless of joint width.

If you have a wide joint (say 1/4 inch) on polished marble, most pros use an unsanded grout formulated with polymer additives instead of sand, which gives you the strength without the scratch risk. These specialty bags cost more, often $30 to $45 per 25 pounds, but they save you from redoing a marble floor. This is the same kind of moisture-and-material tradeoff you see with bathroom exhaust fans that need the right CFM rating for the room size, not just whatever's cheapest at the store.

Does grout choice affect moisture and mold risk in bathrooms?

Somewhat, but sealing matters more than sand content. Both sanded and unsanded cement-based grouts are porous and will absorb water if left unsealed, which invites mildew in showers. A penetrating sealer applied within 48 to 72 hours of grouting, and reapplied every 12 to 18 months, does more to prevent mold than the sanded-vs-unsanded choice itself.

If your bathroom already struggles with moisture, poor grout is often a symptom of a bigger ventilation problem. Check that your bathroom fan is actually venting outside and not dumping humid air into the attic, since trapped moisture will break down grout and caulk far faster than normal shower use. For basements with tiled floors near a sump pump or foundation wall, pair grout sealing with a broader basement waterproofing check so water isn't wicking up from below.

Should you use epoxy grout instead of either one?

Epoxy grout skips the sand-vs-no-sand question entirely because it's resin-based, not cement-based. It costs 3 to 4 times more than standard grout, often $40 to $60 for a 2-gallon kit, but it's non-porous, doesn't need sealing, and resists staining and cracking for 15-plus years. Epoxy is worth the extra cost in kitchens, high-traffic entryways, or rental units where you won't be around to reseal grout on schedule. For a bathroom you'll re-caulk every few years anyway, standard sanded or unsanded grout is usually the more practical call.

FAQ

Can I mix sanded and unsanded grout in the same project?

Yes, if joint widths vary. It's common to use sanded on the floor and unsanded on a glass tile backsplash in the same bathroom, as long as you match each surface to its correct grout type.

How long does grout take to cure before I can use the shower?

Cement-based grout needs 48 to 72 hours to cure before regular water exposure, and up to 7 days before you apply a sealer. Rushing this step is the top reason DIY grout jobs fail within the first year.

Does sanded grout come in different colors?

Yes, both sanded and unsanded grout come in 30-plus standard colors from major brands, and color choice doesn't affect the sanded-vs-unsanded decision at all.

What happens if I use unsanded grout in a wide joint by mistake?

It will likely shrink and crack within a few months because there's no sand to prevent excessive shrinkage as it cures. You'll need to remove it and regrout with the correct sanded formula.

Is unsanded grout more expensive than sanded?

Per pound, yes, typically 10 to 20% more, because it needs additional binder to compensate for the missing sand filler. For small jobs like a backsplash the total cost difference is usually under $10.

This is educational information, not professional installation advice. Call a licensed tile contractor if you're unsure about joint width, substrate condition, or moisture damage behind existing tile.