Grouting materials for ceramic, glass, and stone tiles are available in many forms to meet the requirements of the different kinds of tile and types of exposures. Portland cement is the base for most grouts and is modified to provide specific qualities such as whiteness, mildew resistance, uniformity, hardness, flexibility, and water retentivity. Non-cement-based grouts such as epoxies, furans, and premixed polymer resin grouts offer properties not possible with cement grouts. However, special skills and precautions on the part of the tile setter may be required.

An on-the-job mixture of 1 part portland cement to 1 part fine, graded, clean sand (ASTM C144) is used for joints up to 1/8”in width; 1:2 for joints up to 1/2” in width; and 1:3 for joints wider than 1/2”. Up to 1/5 part lime may be added.

Sand-portland cement grout can be used with ceramic mosaic tiles, quarry tiles, pressed floor tiles, porcelain tiles, some glass tiles, and some stone tiles on floors and walls. Damp curing is necessary. On stone tiles and glass tiles, make sure the surface will not be scratched by the sand in the grout; unsanded grout may be required. Unsanded grout is commonly used with polished calcium carbonate-based stones (see Natural Stone Tile Selection and Installation Guide.) Some glass tile manufacturers require unsanded grout to prevent scratching on smooth glass tile surfaces (see Glass Tile Selection and Installation Guide).

Standard Unsanded Cement Grout: A factory-prepared mixture of cement, fine aggregate, and other ingredients to produce a water-resistant, dense, uniformly-colored material meant for joints 1/8" in width or less water-resistant, dense, uniformly-colored material meant for joints 1/8” in width or greater.

Grouts in this category provide improved characteristics such as increased bond strengths, flexural strengths, and lower water absorption to resist frost damage. On stone and glass tiles, make sure the surface will not be scratched by sand in the grout; unsanded grout may be required. Unsanded grout is commonly used with polished calcium carbonate-based stones (see Natural Stone Tile Selection and Installation Guide.) Some glass tile manufacturers require unsanded grout to prevent scratching on smooth glass tile surfaces (see Glass Tile Selection and Installation Guide).

Color consistency and stain resistance vary depending on several factors: water absorption of the tile (with lower absorption generally producing a lighter shade), grout color chosen, whether polymer or water is used, amount of water used in mixing and cleaning, degree of curing before cleaning, grout compaction, joint depth, joint finishing, humidity, and many other parameters. In-field color can vary significantly from factory-prepared color samples, and many grouts are darker when wet.

While there is currently no industry standard to evaluate color consistency or stain resistance of cementitious grouts, there are grout formulations and/or admixtures available that allow for improved color consistency. Similarly, there are grout formulations, and/or admixtures, and/or sealers that allow for improved stain resistance by reducing the extent or severity of staining. Not all stains are affected similarly; consult grout manufacturers for application suitability and maintenance recommendations.

Regardless of the grout used and whether or not a sealer was applied, tile and grout can generally be cleaned by sweeping first and rinsing with water. In cases where excess dirt cannot be removed, use an alkaline or pH-neutral cleaner at the lowest effective concentration and rinse thoroughly to eliminate residue. Do not use oil-based cleaners, which are difficult to remove and entrap dirt.

Epoxy grout is a grout system employing epoxy resin and hardener portions, often containing coarse silica filler, especially formulated for industrial and commercial installations where chemical resistance is important. These grouts also provide high bond strength, impact resistance, and improved stain resistance. High temperature, chemical-resistant formulas are also available. Chemical and stain resistance can vary between epoxies; consult grout manufacturers for application suitability, including exterior UV exposure and maintenance recommendations.Complete installation and material specifications are contained in ANSI A108.6 and A118.3. For applicable ISO materialspecifications, see ISO RG criteria.

Epoxy emulsion grout is a grout system employing epoxy resin and hardener portions, both of which contain additional water to form an emulsion. The coarse silica filler portion also contains portland cement. These grouts are not designed for chemical resistance nor designed to meet ANSI A108.6 or ANSI A118.3.

Furan resin grout is a grout system consisting of furan resin and hardener portions. Furan grout is used in industrial and commercial areas requiring chemical resistance. Use of this grout requires waxed tiles, special installation skills, and additional safety precautions when compared to all other grouts. Architects should select the type of furan grout applicable to the specified chemical and temperature exposure. This grout is not used with stone or glass tiles.

Premixed polymer resin grout is a one-part liquid ready-to-use grout that requires no mixing with water. These grouts may contain various types of water-based polymer including acrylics or urethanes and fillers that may be sanded or unsanded. The appropriateness of these grouts for commercial, water-exposed, and exterior applications varies widely; review and follow manufacturer recommendations before use.

There are no product or installation standards for this type of grout.