What is the difference between sanded and unsanded grout?

Sanded grout contains fine silica sand, making it stronger and shrink-resistant for joints wider than 1/8 inch. Unsanded grout has no sand — it is smoother, better for narrow joints under 1/8 inch, and required on delicate surfaces like polished marble or glass tile that sanded grout would scratch.

Should I use sanded or unsanded grout for a shower?

For shower walls with joints under 1/8 inch, use unsanded grout. For shower floors or walls with joints wider than 1/8 inch, use sanded grout. Either way, in wet areas you should seal cement grout every 1-2 years, or use epoxy grout (like Laticrete Spectralock) which never needs sealing.

Should I use sanded or unsanded grout for a floor?

Use sanded grout for floors in almost all cases. Floor tile joints are typically 1/8 inch or wider, and sanded grout is stronger and more resistant to cracking under foot traffic. Unsanded grout on floors wider than 1/8 inch will shrink and crack.

Should I use sanded or unsanded grout for a backsplash?

It depends on your joint width. Backsplash subway tile (3x6) typically uses 1/16 to 1/8 inch joints — use unsanded grout. If your backsplash joints are wider than 1/8 inch, use sanded grout. Glass or polished stone backsplash always requires unsanded grout to avoid scratching.

What is unsanded grout used for?

Unsanded grout is used for joints under 1/8 inch, polished marble, glass tile, metal tile, and any surface that sanded grout would scratch. It is also the standard choice for vertical surfaces like shower walls where the sand can cause sanded grout to slump.

Can sanded grout be used in a shower?

Yes. Sanded grout can be used in showers for joints wider than 1/8 inch. It is actually stronger and more durable than unsanded grout in wet areas. However, it must be sealed after curing to prevent water absorption and mold. Epoxy grout is an alternative that requires no sealing.

What is non-sanded grout?

Non-sanded grout is another name for unsanded grout — grout that contains no silica sand aggregate. It is used for narrow joints (under 1/8 inch), polished or delicate tile surfaces, and is smoother and easier to apply on vertical surfaces.

When should you use sanded grout?

Use sanded grout when your grout joints are 1/8 inch or wider. It is the correct choice for most floor tile, outdoor tile, large-format tile, and any joint that needs strength against shrinkage and cracking. The sand reinforces the grout and prevents it from pulling away from tile edges.

Sanded vs Unsanded Grout: The Complete Guide (2026)

CTI-Verified · Updated May 2026

Sanded vs
Unsanded Grout

The complete decision guide — when to use each, why it matters, and how to get it right for floors, showers, backsplash, and walls. Written by a Certified Tile Installer with 18 years in the field.

Marcus Hale, CTI #2847 NTCA Member 18 yrs field experience

Quick Decision Chart Field guide

Floor tile · joints ≥ 1/8"Most standard floors

Sanded

Shower walls · joints < 1/8"Rectified or narrow-joint tile

Unsanded

Shower walls · joints ≥ 1/8"Standard ceramic, subway

Sanded

Shower floor · mosaic tile2×2, penny round

Sanded

Backsplash · subway 3×6Typical 1/16"–1/8" joints

Unsanded

Polished marble / glass tileAny joint width

Unsanded

Large format tile ≥ 12×24Joints 1/16"–3/16"

Either*

This guide covers

Floors Shower walls Shower floor Backsplash Bathroom floor Outdoor tile

Marcus Hale

Certified Tile Installer · CTI #2847 · NTCA Member

18 years setting tile across the Southeast — hotels, hospitals, and high-end residential. I built these guides from the same math I use in the field. About Marcus →

The Core Difference

Sanded vs Unsanded Grout: Side-by-Side

The single most important factor is joint width. Everything else follows from there.

Property	Sanded Grout	Unsanded Grout
Joint width	1/8" – 5/8"	Under 1/8"
Contains sand	Yes — silica aggregate	No aggregate
Shrinkage	Low — sand prevents it	Moderate — cracks in wide joints
Strength	Higher	Lower
Surface safety	Can scratch polished/glass tile	Safe on all surfaces
Vertical application	Heavier, may slump on walls	Easier on vertical surfaces
Price	Mid — ~$18–25 / 25 lb bag	Similar — ~$18–25 / 25 lb bag
Floors	Correct choice	Avoid — shrinks/cracks
Shower walls (narrow joint)	Wrong — may scratch tile	Correct choice
Polished marble / glass	Will scratch surface	Required
Needs sealing	Yes — especially in wet areas	Yes — especially in wet areas
Brands	Mapei Keracolor S, Laticrete PermaColor, CBP Polyblend Plus	Mapei Keracolor U, Laticrete PermaColor Unsanded, CBP Polyblend Plus Unsanded

⚠ The one rule that matters If your joint is wider than 1/8 inch (3mm), always use sanded grout. Unsanded grout in wider joints will shrink away from the tile edges and crack within months — it is not a matter of preference, it is a structural failure.

Joint Width Reference

Which Grout Type by Joint Width

Joint width is measured from tile edge to tile edge. When in doubt, use a 1/8" drill bit as a physical gauge — if the bit fits with room to spare, use sanded grout.

Joint Width	Grout Type	Typical Use Case	Notes
1/16" (1.5mm)	Unsanded	Rectified porcelain, large-format slab	Very precise cuts required at this width
1/8" (3mm)	Either*	Standard ceramic, subway backsplash	Borderline — use unsanded on delicate surfaces, sanded on floors
3/16" (4.8mm)	Sanded	Most standard wall and floor tile	Most common grout joint in residential tile
1/4" (6mm)	Sanded	Slate, travertine, handmade tile	Wider joints need sand to prevent shrinkage
3/8" (9.5mm)	Sanded	Rustic stone, saltillo, outdoor pavers	Consider medium-bed mortar for thick tile
1/2" – 5/8" (12–16mm)	Sanded	Irregular stone, wide-joint decorative	May need custom sand-portland mix for very wide joints
Over 5/8"	Neither	Custom applications	Use mortar or custom grout formulation — standard grout will fail

*At exactly 1/8": use unsanded for polished marble, glass, or any delicate surface. Use sanded for unglazed ceramic, porcelain, and all floors.

By Surface

Which Grout for Each Surface — Specific Answers

The question isn't just sanded vs unsanded — it's sanded vs unsanded for your specific surface and joint width. Here's the breakdown by location.

🏠

Floor Tile

Almost always sanded. Floor joints are typically 3/16"–1/4", and floors take foot traffic — you need the sand's reinforcement against cracking and shrinkage.

→ Sanded

🚿

Shower Walls

Depends on joint width. Under 1/8": unsanded. Over 1/8": sanded. For glass or polished tile in a shower: always unsanded regardless of joint width.

→ Depends on joint

💧

Shower Floor

Typically sanded. Shower floors use mosaic or small-format tile (2×2, penny round) with 1/8"–3/16" joints. Sanded grout is stronger under wet conditions.

→ Sanded

🍳

Backsplash

Subway tile backsplash (3×6) uses 1/16"–1/8" joints — use unsanded. If backsplash is handmade tile or stone with wider joints, use sanded. Glass backsplash: always unsanded.

→ Usually unsanded

🛁

Bathroom Floor

Sanded grout. Bathroom floors are the same as any floor — standard joints (3/16"+) require sanded grout for durability. Exception: polished marble floor, always unsanded.

→ Sanded

🪟

Polished Marble

Always unsanded, regardless of joint width. Silica sand in sanded grout will scratch polished marble permanently. No exceptions. If the joint is wider than 1/8", seal frequently.

→ Unsanded only

🪞

Glass Tile

Always unsanded. Glass tile is highly scratch-sensitive. Sanded grout will permanently etch the surface. Glass mosaic, subway glass, and glass pool tile all require unsanded grout.

→ Unsanded only

🌿

Outdoor Tile

Sanded grout in almost all cases. Outdoor tile uses wider joints to accommodate thermal expansion, and sanded grout is more resistant to freeze-thaw cycling and movement.

→ Sanded

In-Depth Guide

Everything You Need to Know

The science behind the choice — and the contractor details that prevent the most common mistakes.

Why Sanded Grout Contains Sand

Silica sand is added to grout as an aggregate — the same reason concrete contains gravel. When grout cures, water evaporates and the mixture shrinks slightly. Without sand, that shrinkage is significant enough to pull the grout away from tile edges, leaving hairline cracks and gaps that trap moisture and dirt.

In joints wider than 1/8 inch, the shrinkage force exceeds the grout's tensile strength. Sand distributes and resists the shrinkage, keeping the joint intact. This is why unsanded grout in a wide joint will always fail eventually — it is a material physics issue, not a product quality issue.

Why Unsanded Grout Exists

For joints narrower than 1/8 inch, sand particles (typically 0.3–0.5mm diameter) are too large to pack consistently into the joint. The result is a grainy, inconsistent fill with voids — the opposite of what you want. Unsanded grout has a finer, more fluid consistency that fills narrow joints completely.

Additionally, polished stone and glass tile have surfaces that silica sand will physically scratch and etch — permanently. Unsanded grout eliminates that risk entirely. On marble and glass, unsanded is not a preference — it is the only correct choice.

The 1/8" (3mm) Borderline

At exactly 1/8 inch joint width, either product can work. In practice, the decision comes down to the tile surface:

Unglazed ceramic, porcelain, or stone: use sanded grout for strength
Polished marble, glass, metal, or any delicate glaze: use unsanded grout to avoid scratching
On floors at 1/8": always use sanded — the foot traffic demands the strength

Sanded vs Unsanded in the Shower

Shower grout fails more than any other tile installation — and the wrong grout type is frequently the reason. Here's what I see in the field after 18 years:

Shower walls with narrow-joint rectified tile (1/16"–1/8"): Use unsanded grout. The thin joints can't accommodate sand particles properly, and unsanded grout is easier to apply vertically without slumping.

Shower walls with standard ceramic or subway tile (3/16" joint): Use sanded grout. It is stronger, more water-resistant before sealing, and fills the joint more completely.

Shower floor (any format): Sanded grout. Shower floors typically use mosaic tile (1/8"–3/16" joints) and need sanded grout's strength for durability underfoot.

Pro tip: In showers, consider skipping the debate entirely Laticrete Spectralock Pro or Custom Prism are both epoxy/SCG grouts that work in any joint width and never need sealing. For any shower installation, they eliminate the sanded/unsanded decision and the ongoing sealing maintenance.

Single-Component Grouts (SCG): The Third Option

Products like Custom Building Products Prism and Laticrete PermaColor are Single Component Grouts (SCG) — polymer-modified grouts that work in joints from 1/16" to 1/2" without the sanded/unsanded distinction. They contain a fine aggregate that behaves like sanded grout in wider joints but doesn't scratch delicate surfaces.

For most modern tile projects, an SCG like Custom Prism eliminates the sanded/unsanded decision entirely. They cost slightly more but save time and reduce the risk of using the wrong product.

Brand Reference

Sanded & Unsanded Options by Brand

Every major grout brand makes both sanded and unsanded versions. Here's the right product name for each scenario.

Brand	Sanded Product	Unsanded Product	All-in-One Option
Mapei	Keracolor S (sanded) · Ultracolor Plus FA	Keracolor U (unsanded)	Mapei Calculator →
Laticrete	PermaColor Select Sanded	PermaColor Select Unsanded	Laticrete Calculator →
Custom Building Products	Polyblend Plus Sanded	Polyblend Plus Unsanded	Prism (any joint) →
Ardex	Ardex WJ 50 (wide joint)	Ardex FL (fine line)	—
TEC	TEC AccuColor Sanded	TEC AccuColor Unsanded	TEC Power Grout (any joint)
Bostik	Dimension RapidCure (sanded)	Dimension RapidCure (unsanded)	—

FAQ

Sanded vs Unsanded Grout — Questions Answered

The most common questions from homeowners and contractors — answered directly, without filler.

Sanded grout contains fine silica sand, which prevents shrinkage and adds strength in joints wider than 1/8 inch. Unsanded grout has no sand — it's smoother, flows into narrow joints more completely, and won't scratch polished or delicate tile surfaces. The rule is simple: joint wider than 1/8"? Use sanded. Narrower? Use unsanded. Polished marble or glass? Always unsanded.

It depends on your joint width. Shower walls with joints under 1/8" (rectified tile, narrow-joint installs): use unsanded grout. Shower walls with joints 1/8" or wider (standard ceramic, subway tile): use sanded grout. Shower floor (mosaic, penny round, small format): sanded grout in almost all cases. In any wet area, seal cement grout annually — or use epoxy grout (Laticrete Spectralock Pro, Custom Prism) to eliminate the sealing requirement entirely.

Sanded grout for floors in almost all cases. Floor tile joints are typically 3/16"–1/4", and sanded grout is structurally stronger under foot traffic. The only exception is polished marble or glass tile on a floor — use unsanded to prevent surface scratching. Unsanded grout in a floor joint wider than 1/8" will shrink, crack, and fail.

Depends on your tile and joint width. Standard subway tile backsplash (3×6") with 1/16"–1/8" joints: use unsanded grout. Glass tile backsplash: always unsanded, regardless of joint width. Stone backsplash with joints 1/8"–1/4": use sanded grout. When in doubt on a backsplash, unsanded grout is the safer choice because it won't risk scratching the tile during application.

Yes — non-sanded grout and unsanded grout are exactly the same product. "Non-sanded" is simply another name for the same thing. Both terms refer to grout that contains no silica sand aggregate. You'll see both names used at home improvement stores and on manufacturer packaging — Mapei calls it "Keracolor U (unsanded)," CBP labels theirs "Polyblend Plus Unsanded." Same product, different label terminology.

Yes — sanded grout can absolutely be used in showers, and is actually the better choice for shower joints wider than 1/8". It is stronger and more water-resistant before sealing than unsanded grout. The key requirement: seal it after full cure (72 hours) and reseal annually in a wet shower environment. For a maintenance-free alternative, use Laticrete Spectralock Pro epoxy grout — it never needs sealing.

Use sanded grout when: (1) your grout joints are 1/8 inch or wider, (2) you're tiling a floor, (3) you're working with unglazed ceramic, porcelain, or natural stone, (4) you're doing outdoor tile work, or (5) you need maximum durability in high-traffic or wet areas. Sanded grout is the correct choice for the majority of tile installations — the situations requiring unsanded grout are the exception, not the rule.

Unsanded grout has four specific advantages: (1) it fills narrow joints (under 1/8") completely without voids, (2) it won't scratch polished marble, glass, or soft-glazed surfaces, (3) it has a smoother consistency that's easier to apply on vertical wall surfaces, and (4) it has better adhesion for grout-to-tile contact in narrow joints. Outside of these scenarios, sanded grout is usually the better performing option.

Sanded grout for bathroom floors. Bathroom floor tile is installed with 3/16"–1/4" joints in almost every case — that joint width requires sanded grout. The sand reinforcement is essential for a floor that bears foot traffic daily. The only exception is a polished marble bathroom floor, where you must use unsanded grout to avoid scratching the surface. If you're using Custom Prism or another SCG (single component grout), it works for any joint width and handles bathroom floors well.

For most residential projects, Mapei Keracolor, Laticrete PermaColor, and CBP Polyblend Plus are all comparable performers — the type (sanded vs unsanded) matters far more than the brand. Where brand matters: color consistency (Laticrete PermaColor and Custom Prism have slightly more consistent color lot-to-lot), stain resistance (premium polymer-modified grouts like Mapei Ultracolor Plus FA perform better without sealing), and epoxy options (Laticrete Spectralock Pro is the industry standard for no-maintenance wet areas).

Calculators

Calculate How Much Grout You Need

Now that you know which type to use — calculate exact bag counts for your project.