A guide to concrete floor renovation.
By J. McCarthy, with Greg Schwietz, President, L&M Construction Chemicals

There are many different ways to protect concrete floors from general use and abuse. In this article we're going to compare floor coatings to penetrating liquid chemical hardeners. We'll contrast how they look, how much they cost, and how good a job they do of protecting the near surface wear zone of your concrete floor. (In layman's terms, that's the top 1/16 to 1/8 inch of the concrete's wear surface.) We're also going to tell you about a new process, described by some as "abrasive smoothing," which can provide a durable and visually appealing finish that has, until now, rarely been achieved on concrete floors.

Who are the players?
Let's compare four basic methods of floor finishing and protection. Each has its own characteristics, advantages and disadvantages. In order of discussion, they are:

  1. chemically resistant epoxy coatings and moisture-cured urethanes, referred collectively as "thin film coatings,"
  2. conventional floor waxes,
  3. chemical hardeners and densifiers, and finally,
  4. "abrasive smoothing," commonly known as concrete polishing.

Thin Film Coatings
The old saying goes, "Beauty is only skin deep." If that's good enough for you, then there's no better skin than epoxy or urethane floor coatings. In fact, that's exactly what it is: a skin of hard epoxy or urethane resin that protects the top of your concrete floor. Thin film coatings are shiny, colorful, very resistant to chemical attack and stains, and generally resist dusting. But, like all things that are skin deep, they don't always age well.

Buying an epoxy or urethane floor is a lot like buying a new car. It's great when you drive it off the lot, but you can't keep that new-car look forever. While thin film coatings are durable, by their nature they are only temporary. As time goes by, these coatings begin to discolor and show scratches, cuts, chips, and general wear. Depending on the punishment your floor is going to endure, predicting the life of a thin film coating is sort of a crapshoot. Generally, you can count on two to five years. If you're lucky, you'll get by with a sanding and a thin topcoat. But if the coating has deteriorated badly, you'll pull everything off the floor, remove the old coating and put down a new coat.

The cost of a thin film coating can be deceptive. The installed cost of a thin film coating is generally in the range of $2 per square foot. Just be sure your cost analysis includes the cost of preparing the floor for the first application, removing fixtures and equipment, and a significant amount of downtime as the coating cures to full strength. Then, while you're at it, it may be good to figure the ten or thirty-year cost of repeating the same process over and over again. (Don't forget to add a serious chunk of change for old coating removal and disposal.) Remember, depending on the usage, you'll probably find yourself repeating at least part, and maybe the whole process every five years or so. And by the way, plan on doing it over Christmas vacation, or whenever you can block out a few days for a factory shut-down.

Bottom line: Thin film coatings are great to look at and very durable in the short run. But the long-term cost can be high, and they are costly and difficult to remove and replace.

Floor Wax
Want your floor to be shiny? Put wax on it. Want it to be shinier? Put more wax on it. The more you put on, the shinier the floor gets. But the absolute irony about wax is that the more you use, the worse it is. The heavier the coat (or coats) of wax, the more vulnerable the floor is to scratching, cutting, scuffing and general wear.

Are there any advantages to waxing a floor? Yes. It looks like you're saving money and it might seem to be a pretty easy sell to the bean counters, because wax sounds cheap.

But in reality, wax is very expensive. Each cycle includes removal of the previous coats and application of the next new coat or coats, only to be repeated again and again. All in all, you can figure writing a check for up to $1 per square foot each time. Of course, conditions vary, but on average, this cycle is repeated frequently. In the long run, there is no more expensive form of floor coating than wax. Figure the 30-year cost on this and you'll cough up a lung. When calculating the cost of waxy buildup, you must also remember that wax is doing little, if anything, to actually protect the surface of the concrete floor.

Wax looks like...well... wax. It lasts for a relatively short period of time unless you never allow anyone to walk, ride or crawl on it. The higher the shine, the more likely it shows scuffs. So don't expect much in terms of performance. Shopping centers, warehouse stores and women's prisons are all prime candidates for this waxy buildup. Oh, we almost forgot the big advantage. It makes the maintenance contractors very happy because it is a perpetual source of revenue for them.

Bottom line: Wax hurts the bottom line.

Liquid Hardeners and Densifiers Next on the hit parade are liquid concrete hardeners and densifiers. There are a couple of major players in this market: Ashford Formula and L&M Seal Hard. The major brands effectively eliminate dusting and create a fairly nice appearing floor while maintaining the natural slip resistance of concrete. While they are certainly a great improvement over bare concrete, densifiers cannot deliver the shine of an epoxy or urethane. Treated floors, however, develop a medium, easy-to-maintain sheen when regular maintenance discipline is followed. We have found that if the concrete floor surface isn't perfectly smooth to start with, the potential visual appearance of a chemically hardened and densified floor will be compromised.

The big advantage to these products? Once they change the molecular structure of the concrete in the top surface to be harder and denser, the change is permanent. That makes maintenance from that day forward simple and inexpensive. Thin film coatings and waxes just lay there on the floor waiting to wear off. In contrast, a chemical densifier with proper care (which is minimal) reduces the long term maintenance costs and promises low cost, long-term performance that is clearly superior to other treatments. The current installed cost of a chemical densifier is more or less $.25/sq. ft.

Bottom line on liquid hardeners and densifiers:
Thumbs up: Liquid hardeners change the molecular structure of the near surface wear zone, making it denser and stronger. Some do much better than others. (Check out the test data.) First-time application is relatively inexpensive, and it gets less expensive over time. A good applicator with the right liquid hardener will deliver a floor that can last for decades. Most companies that deal in liquid hardeners offer a limited guarantee of 10 years or more. With regular cleaning (automatic scrubber and cleaning solution), the shine gets better over time. Slip resistance remains unchanged from the original bare concrete.

Thumbs down: Since liquid hardeners do not leave a film, they are dependent upon the finish of the concrete for visual appearance. Therefore, they are not as glossy as newly applied epoxies, urethanes or waxes. The flatness and smoothness of the floor before application are critical to the final result. So if the floor surface looks bad to begin with, it's not going to look a lot better after the application of a chemical hardener and densifier. In spite of the appearance, a treated floor will nonetheless be more durable and will maintain its dustproof protection for a very long time.

FGS/PermaShine. Abrasive smoothing, grinding, and polishing old and new concrete floors.
FGS/Permashine is not simply a method for protecting a concrete floor-it is a process for making any concrete floor incredibly dense, smooth and visually appealing. FGS/Permashine is the concrete equivalent of fine sanding hard wood.

The FGS/Permashine process consists of a series of abrasive smoothing steps that, when completed, produces an impressive concrete floor surface, both visually and in terms of durability. When the grinding and polishing steps are combined with the application of a compatible, liquid chemical densifier, the result is a smooth, glossy, durable and attractive concrete floor. It produces an almost mirror-like floor that is exceptionally resistant to wear, dusting, marking and abrasion.

Diamond disc grinder
FGS/Permashine is installed by factory trained and approved contractors who maintain a uniformly high quality standard throughout the industry. The FGS/Permashine process begins by grinding and smoothing a concrete floor with diamond-impregnated abrasive discs that are fitted to large, heavy floor grinding and polishing machines. Depending upon the original condition of the floor to be treated-what the installers call "ground zero"-the first step of the process typically begins with coarse diamond pads that level the floor surface. The process then moves through a succession of steps using progressively finer diamond pads, increasing the smoothness of the floor with each step (similar to progressing from coarse to fine sandpaper when one finishes wood). The original condition of the floor and the desired level of finished polish determine the selection and number of steps. With the assistance of a factory-trained installer, an owner can specify the desired smoothness and light reflectivity.

FGS/PermaShine floor in beverage warehouse
After completing the abrasive smoothing steps, the final step of the process is to apply two coats of a high-performance chemical densifier. (We've already talked about similar products in the previous section of this article.) In our previous discussion of chemical hardeners, we pointed out that the visual results are dependent on the original condition of the floor. But with the FGS/Permashine process, the resultant floor becomes very smooth and reflective. The use of the chemical treatment is necessary to penetrate, densify and harden the exposed cement paste located in the top 1/16 to 1/8 of an inch of the floor. The resulting shine of the smoothing process is quite impressive, and takes concrete floors to a new visual level.

The importance of the chemical densifier cannot be overstated. Its purpose is to hold that shine and to add many years to the expected life of the floor, an important factor when considering the significant cost incurred in preparing and polishing the concrete surface.

High-tech vacuum air filtration eliminates virtually all airborne dust
Would you like yours wet or dry?
There is some debate about whether the grinding process should be done "wet" or "dry." Historically, stone floors and terrazzo concrete have been ground wet, a process that produces a significant amount of wet cement paste or slurry during the coarser grinding steps that must be properly disposed. There are claims that wet grinding eliminates dust during the process.

Yet after careful review of the old methods, and a thorough analysis of the available grinding equipment and vacuum systems, L&M fully endorsed the patented "dry" or water-free process. FGS/Permashine uses vacuum air purification systems that collect the dust during the dry abrasive smoothing process. Vacuum technology claims are made that virtually all airborne dust is eliminated. The dust residue, which is collected in a disposable plastic bag, is safe for disposal in municipal landfills.

Old concrete: New concrete
FGS/PermaShine is effective on old and new concrete. The upside here is that most aged concrete floors can now be economically rejuvenated with the FGS/PermaShine process. Once the floor has been renewed and a regular maintenance program is adopted, you now own a floor that looks very nice and will last for decades instead of years, with a very affordable amount of care. Regular washing with a specially prepared, concentrated cleaner and conditioner solution is all that's needed to keep the floor in first class condition. No need to ever schedule a plant shutdown to do the floor again. While the initial cost of an FGS/PermaShine floor is comparable with an initial installation of thin film coatings, over time its visually appealing finish delivers, to the owner, significant lifetime savings when compared with the other methods we've talked about.

Bottom Line:
FGS/PermaShine delivers an incredibly glossy, smooth, easy to clean, dust-free concrete floor that resists wear and marking for an aesthetically pleasing, long term finish. Unlike thin film coatings, FGS/PermaShine floors actually get better looking with use over time. Not the least of the advantages in time and cost is the fact that this process usually requires no "off-limits" shut-down of the facility. The installed cost of an FGS/PermaShine floor is comparable to a good thin-film coating project. But when you compare the minimal required maintenance, you'll find the 30-year life cycle cost savings over any other floor to be significant.

A final thought...
Each floor treatment we've discussed in this article is better than no treatment at all. Every one of them improves either the appearance or the durability of a concrete floor. The question really comes down to what you expect out of your floor, and how much you're willing to spend short-term and long-term to protect it. FGS/PermaShine is challenging traditional floor finishes, and a serious shakeout is in the making. Only time will tell who's going to end up winning the race for the best floor.

For information about FGS/PermaShine, contact L&M Construction Chemicals at 800-362-3331 or visit

1. Trained Professional installer evaluates floor condition with owner. 2. Patented "Dry" Diamond Grinding process. Grinding steps determined by original condition of the floor. No wet slurry mess. 3. High-performance vacuum systems reduce virtually all airborne dust while grinding and polishing (steps 2 & 4). Residue easily disposed. 4. Finishing steps of polishing continuing with dry diamond pads. Number of steps determined by degree of shine desired by owner.
5. FGS PermaShine hardener/densifier application, insures long term performance. 6. Problem joints and cracks are filled with durable L&M Joint Tite 750, then trimmed. 7. Completed floor regularly maintained with special conditioner/cleaner solution. 8. Finished floor will provide many years of easy to maintain, attractive service.

Back to ConcreteNews

© 2003 L&M Construction Chemicals, Inc. | ConcreteNews Summer 2003.

Subscribe to ConcreteNews