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Ceramic tile grouts play an essential role in the beauty and longevity of tiled surfaces. Often overlooked but crucial, grout serves as the joint filler that holds tiles together, providing stability, preventing water seepage, keeping the installation sanitary and adding a finishing touch to the overall appearance. In this overview, we will explore the world of ceramic tile grouts, investigate the various types, installation methods, pros and cons and innovations. Whether you are a specifier, tile contractor or tile enthusiast, understanding the ins and outs of grouting will ensure your tiled projects will stand the test of time. With so many choices in grouts, it may be difficult to select the proper grout for your project needs.

Things change, the tile industry changed, setting materials improved and grouts got better. A couple of newer premium grouts are the high-performance cement grouts and premixed grouts, which both quickly gained popularity due to their ease of installation, consistent performance and excellent color consistency. While these new grouts are more expensive than traditional Portland cement grouts, the cost per square foot to upgrade to premium grouts is less today since the typical grout joint width is now between 1/8- to 3/16-inch versus the 1/4-inch average gap width that was popular for years when setting tile. In addition, the popularity of large-format tile (LFT) designs versus the smaller tile size of the past requires fewer grout lines per square foot of tile due to increased coverage given the smaller joint widths and larger tile designs used today.

High-Performance Cement Grout

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Cement-based grouts are the most common type and have been around the longest. Photo courtesy of MAPEI

Why a high-performance cement grout? The tile industry started to get away from Monocottura (single-fired) ceramic tile as porcelain was growing. Porcelain was growing because of increased availability, much lower absorption and denser than traditional ceramic tile. The low absorption (≤ .5%) of porcelain tiles made grouting it different. Traditional cement grouts sometimes got efflorescence and took much longer to cure because the tiles were not taking moisture out of the grout. So, there were commonly issues with low grout joints and inconsistent color. To meet the demanding requirements of ANSI A118.7 Specifications for High-Performance Cement Grouts for Tile Installation, most of the High-Performance Grouts use a calcium aluminate cement instead of, or in addition to, Portland cement. These grouts offer improved color consistency, no efflorescence and overall superior performance properties, making this the ideal cement grout for porcelain tile. It certainly will work with all tiles, but was great solution for low-absorption installations. These grouts might be difficult in high temperatures, and with highly absorption tiles the grout can partially or rapidly hydrate. For high temperatures, you would be best to keep the grout stored in a cool area, the water cold for mixing and clean up as you can get it or wait until it cools down. With highly absorbent, tiles you would want to wet down the tiles before grouting.

Premixed Grout

Premixed grouts are relatively new entrants to the market -- boasting color consistency, excellent stain resistance and ease of application. The premixed grout category has evolved and grown over the last five years or more. This high-performance grout category cannot effloresce, has no water added, does not require mixing and is faster to install. This type of grout can be formulated with either a urethane, acrylic or hybrid chemistry. These products typically cure by dehydration unlike cement grouts, which must hydrate to cure. As a result, installations in a high humidity environment can result in a delay in the curing process. Color consistency is another attribute of premixed grout, as many of the grouts from this category are formulated with color-coated quartz versus free mineral pigments. As a result, pigment washout cannot occur as the pigment color is bonded to the quartz particle. Efflorescence is not possible with this grout type because there is no Portland cement present in the formulation. Professional installers like the fact that the material keeps when you are done for the day. At the end of the day, you put the lid back on the bucket and seal it well. You can open the bucket the next day or a few weeks away and start using it. It will match the previously installed area. Most manufacturers do not recommend their premixed grout be submerged; intermittent water is okay, such as for a shower floor. Verify with your manufacturer if you intend to submerge it. This product doesn’t currently have an ANSI Standard. A product and installation standard has been written by MMSA (Materials and Methods Standards Association) and is soon to be out for membership vote. When members pass it, it will be sent next to the ANSI A108 committee to be voted on. We hope to have an ANSI Standard on premixed grout soon.

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Ceramic tile grouts may seem like a minor detail, but they play a major role in the beauty and longevity of tiled surfaces. Photo courtesy of MAPEI

100% Solids Epoxy Grout

Epoxy grouts offer superior chemical and stain resistance, making them ideal for high-traffic areas, manufacturing and commercial kitchens. Epoxy grouts meet or exceed industry standards A118.3 American National Standard Specifications for Chemical Resistant, Water Cleanable Tile-Setting and Grouting Epoxy and Water Cleanable Tile-Setting Epoxy Adhesive for the product standard. The installation standard is A108.6 Installation of Ceramic Tile with Chemical Resistant, Water Cleanable Tile-Setting and Grout Epoxy. Epoxy grout is essentially impervious with less than 0.1% water absorption. Epoxy is considered the most robust grout category with superior stain and chemical resistance. The installation can be more challenging as epoxy grouts are generally two- or three-component mixtures that require special mixing, handling and installation at the jobsite. Installation of epoxy grout by competent tile finisher is not difficult, but it is very different then cement grout. Skin allergies can also occur with a small percentage of installers. This can only occur through direct contact, so it is essential that high chemically resistant gloves up to your elbow be used. Proper PPE (Personal Protection Equipment) are necessary and can help minimize the potential for this reaction. 100% solids epoxy grout is a thermal set product. It cures by a heat reaction. Epoxy grout has higher abrasion resistance, higher bond and compressive strengths than any other grouts.

Most epoxy grout manufacturers have at least two different types of 100% solids epoxy grout -- a standard or non-industrial epoxy and an industrial-grade epoxy grout. The industrial grade epoxy is more resistant to more chemicals. Due to the aggressive nature of the chemicals in most commercial kitchens, it is best to grout the tile using a 100% solids industrial grade epoxy mortar. While in recent years, the trend in grout joints has become narrow, quarry tile in kitchens is commonly 1/4-inch wide. Cementitious-based grout will degrade or deteriorate when subject to the acidic and harsh chemicals of a commercial kitchen. The best choice for grout in commercial kitchens subjected to hot water and pressure cleaning, harsh cleaners, disinfecting chemicals, fatty acids and no rinse cleaners is a high-performance, 100%-solids, industrial-grade epoxy grout meeting or exceeding ANSI A118.3 requirements. Most epoxy grouts are non-sag and are recommended for both floors and walls. Many are approved for exterior applications, but confirm UV stability with the manufacturer.

Cement Grout

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Today, the most popular cement grout is factory prepared polymer modified cement grouts. The polymer is added during production in a water dispersible latex/polymer powder in addition to sand, cement, water dispersing agents, pigments and other ingredients. Photo courtesy of MAPEI

Cement-based grouts are the most common type and have been around the longest. They are known for affordability and durability. There are jobsite mixed sand/cement, factory blended sand/cement and the most common today, factory prepared polymer modified cement grouts. They are available as sanded for grout joints 1/8 to 1/inch in width and unsanded for 1/8- to 1/16-inch grout joints. Sanded grouts can be used on most tiles from Saltillo to ceramic, porcelain and quarry tile. Unsanded is commonly used in wall tile -- soft stones such as polished calcium carbonite based and glass tiles. Factory prepared cement grouts should meet or exceed A118.6 American National Standard Specifications for Standard Cement Grouts for Tile Installation and should be installed following the manufacturer’s directions and A108.10 Installation of Grout in Tilework.

Jobsite mixed sand/cement grout must be pigmented if color is desired. That can be more difficult to control, which is why factory prepared is so heavily used today. Sand/cement grout must be damp cured for proper hydration to occur.

Factory prepared sand/cement grouts come with sand, cement, water dispersing agents, pigments and other ingredients. When properly mixed according to directions, this grout is known to be dense, durable, water resistant and uniformly colored. In the past, installers frequently added a latex admixture instead of water to the grout to get an even denser, stronger, lower absorption grout with excellent color brilliance.

Today, the most popular cement grout is factory prepared polymer modified cement grouts. The polymer is added during production in a water dispersible latex/polymer powder in addition to sand, cement, water dispersing agents, pigments and other ingredients. This dry polymer adds the many benefits that polymer modification does like lower absorption, increased bond and compressive strengths. Commercially available polymer modified grouts have a proven record of performance in commercial and residential projects.

When mixing and installing cement grouts, you must follow the manufacturer’s directions. It is recommended that certain tiles that have a porous or rough textured surface, regardless of the absorption value, be temporarily coated or sealed on the surface only to facilitate grouting. A reasonable amount of thought and planning on the part of the tile setter, before using the selected grouting material, can assure a satisfactory job. Proper and consistent mixing of the grout is critical. The manufacturer for uniform performance and color, batch to batch, accurately measures the raw materials that go into a bag of cement grout. The tile setter should exercise care by measuring the amount of water (or latex additive) used with each bag of cement grout. Considerable shade variations will occur in the same batch of grout if the water/grout proportion varies from bag to bag. Grout should be mixed with as little water as is practical for application. Excess water will reduce the strength of the grout, may dilute the color and invites shrinkage, cracking and efflorescence. Mix the grout thoroughly for uniform color and maximum strength. Extreme care should be used in applying the grout. Tile with high absorption should be wet down with a sponge and water before grouting. Grout should be applied with a rubber float as close to the full depth of the joint as is practical — at least two-thirds of the tile thickness. Setting material high in the joint should be raked out prior to grouting to insure uniformity of color of the finished grout joint. When cleaning the surface of the tile after placing the grout, use the least amount of water possible technique. Excessive water will weaken the joint and possibly cause pinholes, discoloration and shrinkage cracks. A good installation of grout can make a job.

Ceramic tile grouts may seem like a minor detail, but they play a major role in the beauty and longevity of tiled surfaces. Understanding the different types of grouts, their installation techniques and proper maintenance will ensure that your tile system performs for years to come. Whether you are selling in a tile showroom, undertaking a tiling project or hiring a professional contractor, a solid understanding of ceramic tile grouts is an invaluable asset for achieving stunning and enduring results.