SPECIFYING TODAY'S GROUTS
BY DESIGN
Jim Whitfield FCSI, LEED AP is the Director of Technical Services at MAPEI. He is actively involved in tile industry standards committees (TCNA Handbook, ANSI A108 committee), is an NTCA Ambassador and proud member of the National Tile Contractors Association’s Technical Committee, and is currently the President of Materials & Methods Standard Association (MMSA).
Ceramic tile grouts are vital for the beauty and longevity of tiled surfaces. They serve as joint fillers, providing stability, preventing water seepage, maintaining sanitation, and enhancing appearance. This overview explores various types of grouts, installation methods, pros and cons, and innovations. Whether you’re a specifier, contractor, or tile enthusiast, understanding grouting ensures durable projects.
The tile industry has evolved, leading to improved setting materials and grouts. Among the newer options are high-performance cement grouts and premixed grouts, known for ease of installation, consistent performance, and excellent color consistency. Although pricier than traditional Portland-cement grouts, the upgrade is cost-effective due to narrower grout joints and the popularity of large-format tiles (LFT).
High-performance cement grouts
High-performance cement grouts emerged with the rise of porcelain tiles, which are denser and have a lower absorption rate than traditional ceramic tiles. Traditional cement grouts struggled with efflorescence and inconsistent color when used with porcelain. High-performance grouts, meeting ANSI A118.7 specifications, often use calcium aluminate cement to offer improved color consistency, no efflorescence, and superior performance. However, they may pose challenges in high temperatures and with high-absorption tiles. Cooling the grout or wetting tiles before grouting can mitigate these issues.
Premixed grouts
Premixed grouts, featuring color consistency, stain resistance, and ease of application, have grown in popularity. They are formulated with urethane, acrylic, or hybrid chemistry and cure by dehydration. This grout type prevents efflorescence and pigment washout, thanks to color-coated quartz. For example, the user-friendly premixed grout was used in the 7.06-m² mosaic at the Issaquah Salmon Hatchery, installed by volunteers. Read more at https://tinyurl.com/27kt2tue.
MAPEI advises against using premixed grouts for submerged areas but considers them suitable for intermittent water exposure, such as shower floors. In 2024, premixed grouts were included in the ANSI A108 Standards with the new standards ANSI A118.19 for product specifications and ANSI A108.22 for installation.
MAPEI Flexcolor 3D is a professional-grade, ready-to-use (RTU) translucent grout with an iridescent effect finish, available in 10 designer colors that reflect and refract light.
100%-solids epoxy grouts
Epoxy grouts offer superior chemical and stain resistance, ideal for high-traffic areas, manufacturing sites, and commercial kitchens. These grouts meet or exceed ANSI A118.3 specifications. With less than 0.1% water absorption, epoxy grouts are highly robust, featuring higher abrasion resistance, bond strength, and compressive strength. However, they require special mixing, handling, and installation due to their thermal-set nature. Proper PPE, including high chemically-resistant gloves, is necessary to prevent skin allergies.
Epoxy grout’s bond strength proved crucial during the Covid pandemic, helping to complete the Denver International Airport’s Concourse B West expansion under challenging conditions. Read more at https://tinyurl.com/mwy9fd92.
There are standard and industrial-grade epoxy grouts, with the latter offering more chemically-resistant, essential for commercial kitchens facing harsh cleaning chemicals. For exterior installations, MAPEI recommends consulting their Technical Services Department.
Kerapoxy CQ was used in the Denver International Airport project. It is an improved, two-component, 100%-solids epoxy grout and mortar that is non-sagging/non-slumping in joints up to 3/8” (10 mm) in width, water-cleanable and easy to apply. Its proprietary aggregate achieves durable color, making it excellent for countertops, high-traffic areas, and areas needing stain and chemical resistance. Easy to maintain, Kerapoxy CQ will clean to the original color and contains BioBlock technology to help protect against mold and mildew.
Cement grouts
Cement-based grouts are the most common and have a long history of affordability and durability. They include jobsite-mixed sand/cement grouts, factory-blended sand/cement grouts, and polymer-modified cement grouts, the latter being the most popular today. These grouts come in sanded and unsanded forms, catering to different joint widths and tile types. They should meet ANSI A118.6 standards and be installed per ANSI A108.10 guidelines.
Jobsite-mixed grouts require pigmentation and damp curing, while factory-prepared grouts offer controlled color and performance. Polymer-modified cement grouts, with added latex/polymer powder, provide lower absorption and increased strength, making them suitable for various projects, such as the world’s largest mosaic installation at LaGuardia Airport. Read more here: https://tinyurl.com/2kyfu4he.
Proper mixing and application of cement grouts are crucial for uniform performance and color. Excess water should be avoided, as it weakens the grout and can cause issues like pinholes, discoloration, and shrinkage cracks. Wetting high-absorption tiles before grouting and using minimal water during cleanup can enhance the installation.
Grout plays a significant role in tiled surfaces’ beauty and longevity. Understanding the different types, installation techniques, and maintenance ensures lasting results. Whether you’re in a showroom, working on a project, or hiring a contractor, a solid understanding of ceramic tile grouts is invaluable for achieving stunning and enduring results.
MAPEI’s Keracolor U Unsanded Grout is a premium-grade, pre-blended, polymer-modified unsanded Portland-cement tile grout.
Ultracolor Plus Max is an ultra premium, fast-setting, polymer-modified, non-shrinking grout that offers rich and vibrant colors with maximized color depth and color consistency, such as Pure White and Jet Black. This fine-aggregate grout can be used for joint widths from 1/16” to 3/4” (1.5 mm to 19 mm). It features DropEffect technology to reduce surface absorption and repel water, dirt and grime, and MAPEI’s High-Hydrated Cement Technology (HCT) to eliminate common problems such as color consistency and efflorescence