Example of full, consistent hydration in traditional cement-based grouts with new technology. The result is a tighter matrix and continuous, even coloration.

San Diego’s Catamaran Spa features a custom mosaic with porcelain, glass tile and natural stone installed over several different substrates. Achieving even grout color with traditional cement grout was a challenge in this environment, with high moisture, varying grout joint sizes, and different types of tile and stone with different porosities and densities. The tile contractor, Alan Rea of California Tile Company, San Diego, used Prism SureColor Grout.

There’s an old adage in the tile industry that you may have heard: “Grout can make a bad tile job look beautiful, or a beautiful tile job look bad.” Most tile professionals will agree there is a lot of truth to those words. Grout has a profound effect – good or bad – on the finished appearance of an installation. Clean joints and uniform color make for a clean aesthetic, while messy joints and discoloration leave a sloppy impression.

Installers have always had two basic options when it comes to grout: cement or epoxy. Cement-based grouts are the workhorse of the industry and account for the majority of sales. They are user-friendly and easy to clean off the surface of tile after installation, but can result in some applications with shading and inconsistent color after curing. Epoxy grouts, on the other hand, offer superb, uniform color but are much more costly and more challenging to install and clean.

Example of uneven hydration in cement-based grout, resulting in shading and inconsistent color.

Understanding the Differences Between Epoxy and Cement-Based Grouts

Epoxy and cement grouts don’t typically compete with one another because of vast differences in characteristics, workability and price. Because of their cement-free formula, epoxy grouts do not rely on added water and therefore do not exhibit shading, efflorescence or shrinking after curing. They are extremely resistant to staining from acids and harsh chemicals, making them ideal for certain heavy industrial applications such as manufacturing and warehousing, as well as hospitals and laboratories. However, epoxy grouts are usually considered stiff and difficult to work into grout joints, and they are difficult to wash off afterward. And the cost for epoxy is considerably higher – four to six times greater for materials; labor costs are usually double as compared to cement grout.

Standard cement-based grout is quite user friendly, even for consumers and beginner do-it-yourselfers. It’s affordable and available in an incredibly broad palette of neutral and designer shades that complement today’s tile and natural stone. Cement-based grouts are easy to work into joints, and wash off the tile surface quickly and easily afterward. However, traditional cement grouts are susceptible to shading, efflorescence and discoloration as a result of the curing process, and are not as tolerant of acids, harsh industrial chemicals or other staining agents.

Example of even hydration in cement-based grout.

New Science in Cement-Based Grouts Means Epoxy-Like Color Performance

The primary culprit behind color variation in finished installations is uneven hydration of the cement crystals in traditional cement-based grout. When grout is curing, the level of hydration is affected by a number of environmental conditions including temperature, humidity and the porosity of both the tile and the substrate. Properly hydrated crystals will grow as they cure. Under-hydrated crystals do not expand fully, and therefore appear off-color and cause shaded, uneven areas in a finished installation.

New technology actually binds water to the cement crystals in the grout during curing, forcing the crystals to hydrate evenly and achieve even color throughout, regardless of external conditions. The result is a cement-based grout that produces sure, consistent color regardless of ambient conditions, substrate or type of tile.

Because of its tighter matrix and greater density, these new grouts produce hard, dense joints that are more stain-resistant that traditional cement grouts, and just as easy to install and clean.

Epoxy grouts have high chemical resistance and other properties such as uniform coloration and consistency that make them ideally suited to certain applications. Advances in cement formulas mean that some of these properties – uniform color and consistency – are now possible for cement-based grout installations. This should help make every installation look great, and still at a fraction of the cost of epoxy.