The Groutless® Solution to Pinholes in Terrazzo Flooring

For as long as terrazzo has been installed, pinholes have always been a common characteristic of the flooring. To remedy this, a “grouting” process is performed, which is to fill all the voids and pinholes in terrazzo flooring. It is a labor-intensive, painstaking, but necessary and important process to produce the desired finish. Pinholes have always been a point of contention between contractors and architects as to what level is acceptable in the industry.

Today, with epoxy terrazzo being the most commonly specified terrazzo system, this issue has only intensified. Concord Terrazzo Company will discuss in detail what pinholes are and our revolutionary new system for dramatically reducing the number of pinholes initially and throughout the life cycle of an epoxy terrazzo floor.

What are Pinholes?

Pinholes are small air pockets trapped in the epoxy matrix during terrazzo mixing and pouring. When terrazzo is ground to reveal the aggregates, the pinholes begin to appear. These voids are hard to see from a distance, but they are present on the terrazzo floor. Over time, pinholes can affect the shine of a terrazzo floor and can accumulate dirt and grime. For years, terrazzo contractors have addressed pinholes by grouting the terrazzo floor.

Key Facts:

• Pinholes do not compromise structural integrity or floor performance
• Minor pinholes are classified as normal for a terrazzo project
• Pinholes are filled with grout. Acceptability is subjective and is a project-by-project negotiation between the contractor and the architect.

Example of pinholes in a terrazzo floor. Air pockets form tiny circles which installers will grout over

What is Grouting? and Why Does it Matter?

Grouting is the post-grind process of filling pinholes and surface voids with a thin mix of epoxy resin before the final polishing. It is performed color by color across the entire floor.

The grout process, step by step:

1. The installer grinds the floor to expose aggregates and achieve the smooth surface profile
2. A small batch of epoxy is mixed and troweled across the surface, working material into pinholes
3. This is repeated for each color of the terrazzo design
4. Once completed, installers move to the polishing stage

Furthermore, after the completion of a project, if the architect finds the floor finish to be objectionable due to the level of pinholes, the item is placed on the project’s punch list. The resolution is typically very time-consuming and causes great expense for the terrazzo contractor to resolve.

Even after the acceptance of the new floor. New pinholes may appear during the floor’s lifecycle, commonly caused by regular floor maintenance. Often, the terrazzo contractor is not brought back to fix the issue due to its cost and time requirements. With regular maintenance, recommended sealers will typically fill and close the majority of tiny pinholes.

Installers grouting terrazzo using our original TERRAZZCO EZPour Epoxy 158 formula, which we updated to Groutless® in 2019.

A Groutless® Solution

At Concord Terrazzo Company, we’re constantly exploring innovative ways to improve all of our terrazzo products to benefit the environment and the people who interact with our terrazzo floors. In addressing the issue of pinholes in epoxy terrazzo floors, we developed a revolutionary new formula called TERRAZZCO® Groutless® EZPour Epoxy 158.

TERRAZZCO® Groutless® EZPour Epoxy 158 is a pigmented, 100% solid (VOC-free), two-part epoxy resin system formulated to cure with dramatically fewer pinholes thus reducing the amount of labor required in the grouting phase of any terrazzo project. This factor leads to lower labor costs and reduces the installation time. In addition to dramatically fewer pinholes during the installation process, the terrazzo floor is also less likely to develop new pinholes commonly caused by regular floor maintenance during the life span of the floor.

At the time of development, various terrazzo contractors conducted test trials for Concord Terrazzo Company using the new Groutless® formula. Here were the measured outcomes:

• Dramatically fewer pinholes in 100% of test installations
• No grouting required in over 50% of installations
• Reduced labor hours per square foot in the finishing phase
• Fewer punch list items related to surface finish quality
• Reduced the recurrence of lifecycle pinholes after initial years

How Can Groutless EZPour Epoxy 158 Help You?

Architects:

• Quality Finish: Confidence that the floor finish meets quality standards

Contractors:

• Cost Reduction: Eliminating the need for grouting material increases margins for contractors
• Time Savings: Fewer grouting cycles help contractors complete projects faster
• Simplicity: Terrazzo is installed as usual, but with better outcomes and fewer punch list items

Navicent Health Children’s Hospital – Terrazzo Floor using Groutless®

Navicent Health Children’s Hospital is a high-profile healthcare project that uses TERRAZZCO’s Groutless EZPour Epoxy 158. Healthcare environments present the highest maintenance intensity of any commercial category. Groutless achieved the cleanest achievable post-grind surface with fewer punch list items.

Frequently Asked Questions

Conclusion

Grouting can be a daunting task for many terrazzo installers and an exasperation with architects. Groutless® benefits installers by reducing bodily stress over the course of their careers while helping terrazzo contractors and architects reduce labor and material costs while helping to expedite project completion times and increasing the overall satisfaction of a terrazzo’s finish for years to come.

If you are interested in eliminating the issue of pinholes from a terrazzo project while maintaining the highest level of quality, request or specify TERRAZZCO® Groutless® EZPour Epoxy 158 and see for yourself how our new Groutless® is an industry game-changer. For inquiries please email us at info@terrazzco.com.