Key insights from Custom Building Products
In a recent educational NTCA Webinar hosted by Custom Building Products, Commercial Architectural Service Representative Jim Tuttle delved into the nuances of grout selection for tile and stone projects.
Why grout matters
“Your choice really matters,” Tuttle emphasized, setting the tone for the discussion. Grout is more than just a filler between tiles; it significantly impacts the durability, aesthetics, and performance of tile and stone assemblies. Selecting the correct grout type can make the difference between a project’s long-term success and avoidable failures.
Planning for success
When planning for a successful grout installation, several factors must be considered to ensure durability, functionality, and customer satisfaction. These include:
- Proper design and choosing grout based on service demands, location, and application needs.
- Assessing site scenarios and working with manufacturers and installers to ensure correct placement and techniques.
- Evaluating the need for sealers, selecting appropriate cleaners, and developing a maintenance program.
Grout’s great expectations
Grout comes with great expectations, including achieving color uniformity and perfectly matching the customer’s chosen shade. It must offer durability by ensuring hardness to prevent grout from breaking out of joints and providing abrasion resistance for high-traffic areas. Strength is also essential, with flexural and tensile properties to accommodate movement. Additionally, grout should prioritize cleanability and resistance, offering stain resistance, chemical resistance, and heat resistance to ensure long-term performance and customer satisfaction.
While grout must meet these expectations under ideal conditions, real-world applications often introduce variables such as climatic conditions, tile substrate porosity, and installer skill level. Proper planning and collaboration can bridge the gap between expectations and reality for a successful tile assembly.
Proper grout joint size
The primary purpose of grout is to support and protect the edges of tiles by filling the spaces between them. While this functionality is straightforward, grout can also serve as a design element by complementing or highlighting the tile with color. Proper grout joint size is critical for both structural integrity and aesthetics, and its dimensions must adhere to guidelines established by the American National Standards Institute (ANSI) and Tile Council of North America (TCNA).
The minimum grout joint size is 1/16″, as specified in the TCNA Handbook. However, the joint must also accommodate the tile’s facial dimension variation. To ensure consistency and avoid gaps or misalignments, the grout joint should be at least three times the variation in the tile’s dimensions. For example, if a tile has a variation of 1/16″, the minimum grout joint size should be 3/16″.
For large-format tiles, which are defined as any tile with a side measuring 15″ or longer (with recent classifications extending this to 23″ or more), additional guidelines apply. Rectified tiles, which are precisely cut, require a minimum joint size of 1/8″. Calibrated tiles, which are non-rectified, need a minimum grout joint size of 3/16″. Properly sizing grout joints not only ensures a successful installation but also prevents design challenges, such as uneven edges or unsightly gaps, that can arise when tile dimensions vary. By following these standards, installers can achieve both functionality and a polished, professional appearance.
Current grout standards
ANSI grout classifications provide essential guidelines for selecting the appropriate grout for tile installations, ensuring both performance and durability. These classifications include various types of grout tailored to specific applications and conditions.
- ANSI A118.6 covers standard cementitious grouts, widely used for residential and light commercial projects.
- ANSI A118.7 defines high-performance cement grouts, which offer enhanced stain resistance and durability for more demanding environments.
- ANSI A118.3 specifies chemical-resistant, water-cleanable epoxy grouts, popular for their superior strength and stain resistance, particularly in commercial and industrial settings.
- ANSI A118.8 addresses modified epoxy emulsion grouts.
- ANSI A118.5 covers chemical-resistant furan grouts, though these are less commonly used.
- The latest classification, ANSI A118.19, introduces pre-mixed organic grouts, reflecting advancements in ease of use and technology.
By adhering to these standards and understanding the properties of each, manufacturers, specifiers, and installers can ensure grout meets the performance requirements for each unique project.
Performance comparisons
Tuttle compared the performance of different grout types highlighting their unique properties, strengths, and limitations to help participants make informed decisions. For example, while epoxy grouts offer unparalleled stain resistance, their application can be more labor-intensive and requires precise handling.
Similarly, high-performance cement grouts bridge the gap between traditional cementitious grouts and epoxies, offering enhanced stain and crack resistance while maintaining ease of use.
Grout classifications and installation tips
Participants learned to evaluate grout classifications and specifications for their intended use. Tuttle provided actionable recommendations for specifying the proper grout based on factors like:
- Type of tile or stone as the porosity and material type significantly influence grout choice.
- Installation environmental considerations like moisture exposure, temperature fluctuations, and traffic levels are critical.
- Aesthetic preferences as the color and texture of grout play a vital role in achieving the desired design outcome.
Practical guidance for success
In addition to theoretical knowledge, Tuttle offered practical advice to ensure successful installations. He emphasized proper surface preparation, mixing techniques, and curing times to maximize performance. “Getting it right the first time is more important than doing it fast,” he reiterated, underscoring the importance of diligence and precision.
By understanding the science and application of grout, architects, specifiers, and installers can elevate the quality of their projects and deliver lasting value to clients. Whether you’re designing a sleek modern kitchen or a robust industrial workspace, grout – and your choice of it – truly matters.
Check out the full webinar here.
Elena Grant
Elena Grant is the Assistant Executive Director of Marketing, Communications and Public Relations for the National Tile Contractors Association and Publisher of its publication TileLetter. Grant has over 20 years of experience leading marketing initiatives, programs, and operational enhancement strategies. As Publisher of TileLetter, she oversees all print and digital communications for the publication.
