Much of the 388,800 square feet of space at the Bartle Hall convention center in Kansas City, Mo., has polished concrete floors.
Prosco Much of the 388,800 square feet of space at the Bartle Hall convention center in Kansas City, Mo., has polished concrete floors.

Finished concrete flooring has grown explosively in the past few years, with many new products benefiting applicators and owners.

It has evolved from simply scrubbing and sealing floors to grinding, coloring, and polishing. The industry has developed products that contribute to LEED points and create virtually no waste. We have UV-stable colorants that also harden and densify concrete.

The innovations for finished concrete flooring are coming fast and furious, and it started with densifiers. Typically, manufacturers refer to these products as hardeners/densifiers. Densifiers themselves actually work on several levels, densifying or hardening the surface, inhibiting surface dusting, and most importantly, increasing abrasion resistance.

Potassium- and sodium-silicate densifiers have improved the durability of concrete roads, slabs, and floors for more than 70 years. Application procedures vary according to product. A contractor sprays, brushes, or rolls the liquid densifier onto the concrete, and then scrubs it in to help penetration. What doesn't penetrate must be flushed away before it forms a hard white deposit.

Increasingly strict environmental regulations have added more steps to the process: containment, collection, and proper disposal of the waste stream from flushing. The benefits: concrete that has dramatically improved stain resistance, abrasion resistance, and that no longer “dusts.”

New products

Just as our work, communication, and travel have become faster and more streamlined, so have densifiers.

Lithium-silicate densifiers arrived several years ago. They have gained acceptance because they reduce waste on jobsites and meet the needs of accelerating construction schedules.

These products work the same way as their sodium- and potassium-silicate predecessors, and provide the same benefits. They penetrate concrete pores and react with soft calcium hydroxide in the concrete left from curing. The product of that reaction is hard calcium silicate hydrate—the same material that makes cured concrete hard to begin with.

The big difference is that lithium-silicates penetrate without scrubbing or adding large amounts of water. This saves time, money and energy. They also penetrate completely, which eliminates flushing, waste containment, collection, and disposal—and their costs.

If concrete is oversaturated, lithium-silicate densifiers dry into an inert white powder that can be easily swept away. While saving time benefits installers and clients, removing the waste stream benefits the environment.

Lithium-silicates also benefit the environment by offering three or more times the coverage rate of older products. This means less packaging, lower fuel and transportation costs, and reduced environmental impact.

With an easier densifying process, you can achieve finished concrete floors. Many complementary products and procedures have sprung up.

Polishing, once limited to the stone and terrazzo industries, has been adapted to concrete floors. Densifying makes polishing speedier with better results. With today's lithium-silicate densifiers, eliminating scrubbing, flushing, and waste, polishing is now a more realistic option.

This may partially explain the dramatic growth of these unique, beautiful and durable floors, from big box stores like Wal-Mart to offices, schools, and even churches.

Color, once largely limited to hazardous acetone and acid stains, is now available in an infinite variety of safe, UV-stable, water-based stains and pigments for indoor and outdoor concrete, and polished or unpolished surfaces.

New high-tech protective treatments, combined with advanced burnishing techniques, can make even unpolished concrete gleam and shine.

As owners reach out for these unique and sustainable flooring options, our industry is responding with innovative products and techniques. Finished concrete floors are on their way to being as mainstream as carpet, tile, wood, and other common flooring options.


But we're not there yet, and we won't be until installers and owners understand and accept one crucial point: maintenance.

Aren't concrete floors indestructible? Until this myth is cleared up, finished concrete floors and the people who grind, polish, and coat them will never come into their own. All floors must be cleaned and maintained, especially those subject to foot and vehicle traffic. Finished concrete floors need less maintenance than other floors, but they still need it.

The reason is grit—tiny abrasive dirt and dust particles that come from inside buildings or get carried in on your shoes. Once it is inside a building, walking around or pushing a shopping cart helps grit grind away at the finish of concrete floors.

Traditional cleaning agents can dull concrete finishes, and their acidic components can damage the floors. Our industry has responded with maintenance cleaners that are specifically made for finished concrete floors.

New cleaners contain lithium-silicate, which finds, hardens, and densifies any un-reacted parts of the concrete. This not only keeps floors clean, but keeps abrasion- and stain-resistance at top levels.

Finished concrete flooring will soon be the go-to flooring choice for offices, homes, and hospitals—all the places we're only now making inroads. As we identify new needs and problems, applicators and manufacturers will continue to develop the products and procedures to address them.

A polished concrete floor in a Sobeys store, the second largest grocery chain in Canada.
A polished concrete floor in a Sobeys store, the second largest grocery chain in Canada.

The “clean-up on aisle two,” which can stain a polished or burnished concrete floor, is closer to being solved, thanks to this kind of cooperation.

Other advances will include complete systems to maximize abrasion resistance, tests that show where sealers are not working, and improved penetration of sealers and densifiers to increase their effectiveness and service lives.

The concrete flooring industry is evolving and learning at the same time. Working together, we will help our growing industry reach its full potential. That's good news for all concrete flooring professionals, as well as a sustainable environment.

Joe Reardon is Concrete Products Group Specialist with PROSOCO.;