Students attend NTCA Workshops to learn proper technique for both cement and epoxy grouts. Photo courtesy of NTCA.

Several years ago, NTCA published an article by one of our members titled “Epoxy is a Four Letter Word.” It was one of our most popular, yet controversial articles. The reason for this is simple. Many people in our industry maintain that epoxy grout is extremely difficult to work with. In addition, they contend that the extra labor required to apply it is hard to collect from the consumer or project owner. This was the premise supplied by the author, and many a contractor called or wrote to us echoing this stance.

Indeed, my first experience with epoxy grout almost twenty years ago was equally unpleasant. I spread too much of the grout over the area at once and spent the entire evening trying to get it off of the tile. This was completely my fault but indicative to the negative perception of epoxy that was prevalent at the time and for some remains so today.

Another group of people wrote to us at the time the article was printed to protest the angle taken on the subject. They claimed epoxy grout technology had improved significantly and if you just tried some of the newer products that were being developed, you would be convinced. They were right.

Before I talk a little about new epoxy grout technology, I would like to take a few moments to thank grout manufacturers in general for the tremendous improvements that have been made in cementitious grouts. This article is about epoxy, but I can tell you this much. In the last several years the number of calls we receive in relation to grout problems is significantly diminishing. I believe this is because the grouts we use today are simply higher performance products than the ones we have worked with in the past.

When to use epoxy vs. cement grouts

In the past it was generally recommended to specify and install epoxy grout only when absolutely necessary, such as areas subject to extremely high traffic or chemical abuse. If epoxy grout was requested in a residential application, the distributor or contractor most likely tried to talk the builder or consumer out of the selection. Today, thanks to the improvements in the performance of epoxy grouts, residential areas like kitchen floors, backsplashes and countertops, to name a few, due to their exposure to food and chemical stains, are a natural fit for the specification and application of epoxy grout.

It is not my intent to promote epoxy grout over cement grouts. This is a decision that is based on choice, application, price and performance. Many homeowners would gladly pay more money for the epoxy product and the extra labor required if it might help to prevent stained grout in their home. However, cement grout may perform very well in many of these applications as well.

Epoxy and Porcelain: terms can cause confusion

You have probably heard that not all porcelain tile is porcelain. Or certainly it is difficult to tell if it is or if it is a high quality porcelain tile. Epoxy grout can also create confusion. You must carefully read the technical product data and the installation requirements of each grout manufacturer. Some epoxies conform to ANSI A118.3 (100 Percent Solid Epoxy) while others are designed to meet criteria set forth in ANSI A118.8 (Modified Epoxy Emulsion Mortar/Grout). It is important to know the difference in properties and characteristics.

Like the name implies, 100 percent epoxy is essentially a solid system with no water present in its properties. It generally consists of two or more parts to be used for mixing. Water is used in the clean up process. It consists of epoxy resin, pigments for color, silica fillers and a hardener. Some manufacturers supply colored silica, eliminating the use of pigments, which at times has caused staining in some tiles.

Modified epoxy grout contains a percentage of Portland cement in it. The specifier and installer need to understand the difference and expected performance criteria for both product types.

Improvements in performance recently include the ease of mixing, installation, and in cleanability with water. It is almost amazing for those of us who have been in the business for many years to work with some of the newer epoxy technology.

The new epoxies, when stored properly and mixed according to installation instructions, clean up relatively easily with water. Photo courtesy of Laticrete.


Sometimes we get so caught up in the performance of products that we do not study the Limitations as set forth in the technical data sheets. The purpose of this article is not to compare one epoxy to another. However, each manufacturer lists limitations and sometimes there are glaring differences in products that meet the same standards criteria. One area to scrutinize is whether or not the epoxy is recommended as a mortar to install tile or stone with.

Exterior installations are another key application to become familiar with. Some manufacturers do not recommend epoxy grouts in exterior areas; some do. Some concerns are prolonged exposure to the sun may darken certain lighter colors. Excess heat can react with epoxy at times, potentially causing de-lamination when it is used as a mortar. This is very important if you are considering the product for an exterior install. Fluctuations in temperature when the epoxy is stored in the container or when it is about to be applied as a mixed product can affect its workability. In all instances, it is recommended to include specific installation instructions and product characteristics in your submission or project file.

Although epoxies are extremely high performing in relation to chemical stains, they are not meant to replace waterproofing membranes when the specification calls for them to be installed.

New technology

As stated earlier, improvements in epoxy technology are occurring at a rapid pace. In addition, new technologies are entering the market that claim to perform as well as epoxy in relation to stain resistance. Although there is currently no standard for this system, a urethane based sanded grout for ceramic, porcelain, and natural stone recently was introduced to the trade. The product was designed as a grout only and is not a recommended setting mortar. However, some installers are touting the product performance in areas such as flexibility, strength and adhesion qualities.

Final notes

The epoxy technology explosion is difficult to explain without comparing one product to another. Some of the newer products are easier to work with and clean up, but do not contain all the performance criteria necessary for all applications on some commercial and residential installations. A strong partnership with your installation manufacturer will allow you to educate yourself with these products. One of the most important decisions to be made is what product to use for what application. Over-selling these products in areas where it is not necessary can be cost-prohibitive in both labor and materials. More importantly, using certain epoxies in areas where they are not recommended can be instrumental in an installation failure.

When used properly, however, these new products are playing a very important role in the growth of our trade. More consumers and project owners will select ceramic tile and natural stone if they can proceed with confidence that the grout will maintain its new look throughout the duration of the installation. We have our mortar and grout manufacturers to thank for this.