QUESTION: How important is it to read and follow manufacturers’ technical data sheets?
ANSWER: In today’s marketplace, you can choose from a host of different overlay products. While it’s great to have such a wide array of choices, you’ll discover that each system is unique and may have different requirements for surface preparation, mixing application, and curing.
For example, some manufacturers may require shotblasting for surface preparation, while others say acid etching is sufficient. Some systems require application of a primer, while others simply require the concrete to be saturated surface dry, or SSD, which means the permeable voids are filled with water but no water is on the exposed surface.
That’s why it’s absolutely essential to read, in their entirety, the technical data sheets provided with every product you use. Manufacturers write these specifications for a reason, and it’s crucial to adhere to their guidelines. You will find an abundance of valuable information in the typical tech data sheet for an overlay, including:
- Coverage rates
- Product shelf life
- Recommended applications and product limitations
- Surface preparation guidelines
- Mix ratios and required mixing times
- Application procedures
- Coloring methods
- Cure times
- Suggested sealers
- Protection and maintenance of the finished floor
- Performance data such as compressive strength and abrasion resistance
To save time or a few pennies per square foot, installers often are tempted to waver from the manufacturer’s suggestions on mix ratios, troweling times, or how to properly prepare the substrate. But it's imperative to stick to the instructions in the tech data sheets. And those guidelines should supersede the general advice given in my book. Even if you think your way is better, you risk voiding product warranties by not following the manufacturer’s directives.
I advocate sticking with one manufacturer’s product line after finding a system that works well for a particular application. For example, I won’t mix one manufacturer’s polymer with a different manufacturer’s bagged mix and then apply another manufacturer’s sealer. Whenever possible, I use a complete system.
That said, professional installers may combine systems from different material suppliers if one manufacturer doesn’t offer a specific product they need to achieve a certain effect. Before doing this, consult with a technical rep to learn about products’ compatibility from other sources.
We go one step further at our facility. We conduct extensive testing when combining products from different manufacturers to check compatibility and performance. We install a trial placement and put the surface under extreme conditions, such as driving a forklift over it. Before combining products from different suppliers on a project, conduct similar performance tests to ensure you’ll get the results you expect.
Bob Harris, founder of the Decorative Concrete Institute, Temple, Ga., and senior decorative concrete consultant for Structural Services Inc., has more than 25 years of experience in the construction industry. He conducts seminars in architectural and decorative concrete worldwide, is involved with numerous associations, and is a popular speaker at World of Concrete and other events. The information in this article is based on Bob Harris’ Guide to Concrete Overlays & Toppings, which now comes with a DVD that provides step-by-step instructions for rejuvenating floors and exterior finishes. Visit www.decorativeconcreteinstitute.com.