Tile Grout Types: Sanded, Unsanded, Epoxy, and More
Grout selection is a structural and aesthetic decision that affects tile installation longevity, waterproofing performance, and maintenance requirements across residential and commercial applications. The four primary grout classifications — sanded, unsanded, epoxy, and specialty variants — each carry distinct mechanical properties, joint-width requirements, and substrate compatibility considerations. Misapplication of grout type is one of the most cited causes of tile failure identified during inspection. Understanding how each type functions, where it applies, and what standards govern its installation is essential for anyone navigating tile project specifications.
Definition and scope
Tile grout is a cementitious, resin-based, or hybrid compound used to fill the joints between tile units after they have been set in mortar or adhesive. Its primary functions are to prevent moisture infiltration, stabilize tile edges against lateral movement, and provide a finished aesthetic surface.
The Tile Council of North America (TCNA Handbook for Ceramic, Glass, and Stone Tile Installation) is the primary industry reference that classifies grout types and maps them to installation methods. The American National Standards Institute standard ANSI A108.10 governs the installation of grout for ceramic tile, stone, and glass applications and defines acceptable joint widths, mixing ratios, and curing procedures.
The four major grout categories are:
- Sanded grout — Portland cement base with fine aggregate (sand) filler; formulated for joints 1/8 inch (3.2 mm) and wider
- Unsanded grout — Portland cement base without aggregate; formulated for joints narrower than 1/8 inch
- Epoxy grout — two- or three-part system combining resin, hardener, and filler; not cement-based
- Specialty grouts — includes urethane grout, furan resin grout, and modified hybrid formulations designed for specific substrate or chemical exposure conditions
How it works
Sanded grout achieves dimensional stability through the mechanical interlock of aggregate particles within the cement matrix. The sand prevents excessive shrinkage as the cement cures, which is critical in joints wider than 1/8 inch where unsupported cement paste would crack. Standard sand particle size ranges from 35 to 50 mesh. Polymer-modified versions incorporate latex additives to improve flexibility and adhesion.
Unsanded grout relies on the cement paste itself to fill and bond within narrow joints. Because it lacks aggregate, it flows into tight spaces without abrasion risk to polished surfaces — a critical property for marble, glass mosaic, and rectified porcelain tiles where scratch damage from sanded product is a documented failure mode. Joint width must remain below 1/8 inch to prevent shrinkage cracking.
Epoxy grout hardens through a chemical reaction between resin and hardener components rather than through hydration. Once cured, epoxy grout achieves compressive strength values exceeding 5,000 psi in standard formulations — significantly higher than Portland cement grouts, which typically fall in the 1,500–3,000 psi range. The TCNA Handbook classifies epoxy as the preferred grout type for chemical resistance applications. Epoxy grout is appropriate for joints from 1/16 inch to 1/2 inch depending on filler ratio.
Furan resin grout, used in industrial settings with concentrated chemical or acid exposure, requires a different primer system and skilled application. The Occupational Safety and Health Administration (OSHA) classifies furan resin components as chemical hazards requiring appropriate PPE; Safety Data Sheets (SDS) must be maintained on-site per 29 CFR 1910.1200.
Common scenarios
Floor tile in high-traffic commercial spaces — Sanded grout with polymer modification is standard for joints of 3/16 inch or wider in floor applications. The TCNA's Method F113 specifically addresses large-format tile flooring where 1/4-inch to 3/8-inch joints are common.
Glass mosaic backsplashes — Unsanded or non-sanded epoxy grout is required. Sanded product abrades glass surfaces and compromises tile integrity.
Commercial kitchen and food-service environments — Epoxy grout meets the sanitation requirements established by the National Sanitation Foundation (NSF International) for food-contact surface adjacency. Its non-porous cured surface resists grease, acids, and cleaning agents that degrade Portland cement grout.
Wet areas, showers, and steam rooms — ANSI A108.10 and TCNA Method B415 require grout with demonstrated water resistance. Epoxy or polymer-modified sanded/unsanded grouts are specified over straight Portland cement in continuously wet conditions.
Exterior tile in freeze-thaw climates — The freeze-thaw cycle degrades standard cementitious grout by expanding trapped moisture. ASTM International standard ASTM C1245 addresses freeze-thaw resistance for tile installation materials; specifiers in USDA Plant Hardiness Zones 1–6 typically require polymer-modified or epoxy grouts per project engineer direction.
Decision boundaries
The joint width measurement is the primary determinant in grout selection:
| Joint Width | Grout Type |
|---|---|
| Less than 1/8 inch | Unsanded only |
| 1/8 inch to 3/8 inch | Sanded (standard or polymer-modified) |
| 1/8 inch to 1/2 inch | Epoxy (all joint widths) |
| Over 1/2 inch | Sanded or specialty; consult TCNA method |
Secondary determinants include substrate chemistry, exposure classification, and local building code requirements. Permits for commercial tile work in jurisdictions following the International Building Code (IBC) may trigger inspection of wet-area assemblies where grout type is a material specification item. Inspectors in these jurisdictions reference the TCNA Handbook as a basis for code-compliant installation review.
Professionals listed in the tile listings directory on National Tile Authority hold classifications spanning sanded/unsanded cement work through licensed epoxy and chemical-resistant grout installation. The tile-directory-purpose-and-scope page outlines how installer categories map to these grout classification tiers. For a structured orientation to how this reference resource is organized, the how-to-use-this-tile-resource page describes the directory's classification methodology.
References
- TCNA Handbook for Ceramic, Glass, and Stone Tile Installation — Tile Council of North America
- ANSI A108.10: Installation of Grout — American National Standards Institute
- ASTM C1245: Standard Test Method for Freeze-Thaw Resistance of Tile Materials — ASTM International
- OSHA 29 CFR 1910.1200: Hazard Communication Standard — U.S. Occupational Safety and Health Administration
- NSF International — Food Equipment Standards
- International Building Code (IBC) — ICC Digital Codes