This is not groundbreaking stuff!

Just follow these tips to properly prepare, care for and repair your concrete floors

by Dave Bongiori

Proper maintenance of concrete floors can save time and money in the long run. 

Spotting the early warning signs of deterioration can head off a major problem. 

Better yet, choosing the right protective coating and applying it carefully when the floor is new can prevent problems for years.

Given the many uses of concrete floors today, there are a host of excellent coating and patching products on the market. When planning a new floor, a facility manager should know what kind of wear and tear the floor must withstand. The choice of coatings depends on the nature and extent of expected foot and machine traffic and to what degree that traffic will be dispersed across the floor or directed along wear-prone corridors. As with most endeavors, haste makes waste — advance research and consultation with the manufacturers of floor coatings is well worth the time.

Safety is paramount. 
Some coatings are more slippery than others, but most are slippery when wet. Depending on the anticipated use, a walkway, a ramp, a loading platform, or even an entire floor may require an anti-slip coating containing an additive such as silicone carbide granules for a rough finish. For different anti-slip finishes, separately purchase grit such as walnut shells or silica and mix them with the coating prior to application. 

Durability is another prime consideration. 
Floors that may come in contact with fuels, solvents or other harsh chemicals may need tougher coatings, not only for floor durability but also for ease of routine cleaning and spillage cleanup. Some chemical-resistant coatings are specifically formulated for use on concrete surfaces in the vicinity of chemical storage tanks (piping, dike walls, containment areas, etc.).

Ease of application
The best floor coatings can be easily applied by brush, roller or squeegee without special equipment or training. To minimize employee exposure to harmful fumes during application, it’s best to choose a 100-percent-solids coating, which contains no volatile organic compounds (VOCs). Self-leveling coatings save hours of labor. For a large job, a coating packaged in containers holding three gallons or more also saves time.

Before choosing a floor coating, study the manufacturer’s specific application instructions. Here the buyer will encounter many variables — curing time, curing temperature, thickness per coat, mixing ratio, pot life, coverage per container and surface preparation, to name a few.

Proper surface preparation is essential to ensure coating adhesion. In all cases, the floor must be sound, rough, clean, oil-free and dry. Allow newly poured concrete to cure for 28 days prior to preparation. Power washes or steam cleaners are very effective and reduce cleaning time, but multiple cleanings still may be necessary.

If a curing membrane or cap-curing agents were used on new concrete, you must remove them. Shotblast the new floor or etch it with acid to create a porous surface profile. Environmentally safe acids, such as citric acid, are available. However, etching is not a substitute for degreasing. Perform etching after the surface is degreased. Rinse the floor several times after etching to neutralize the acid.

For older concrete, remove all loose or unsound concrete by chipping, scarifying, shotblasting, sanding or grinding. After washing with a grease-cutting detergent, rinse the floor several times.

For previously painted or coated concrete, conduct a spot test to make sure the new coating will bond to the old surface. It is advisable to wait five days and then scrape the test area with a sharp instrument, or cut an “X” into the surface, place pressure-sensitive tape firmly over the cut, and remove the tape with a hard, fast pull. If the new coating fails either test, remove the old finish with a sander or paint stripper.

Shotblasted or etched concrete usually requires the application of a primer to penetrate the surface prior to applying the chosen protective coating. It is important that the primer is formulated specifically for the chosen coating, and that the manufacturer’s instructions are followed to the letter.

Repairs
By watching a concrete floor for signs of deterioration, a maintenance crew can usually stay on top of the aging process and ensure that all repairs are minor ones.

Obviously, the choice of a grout or patching compound depends on the nature of the problem. As with choosing an initial coating, effective repair of a concrete floor first requires choosing the right product for the job at hand. Many of the variables to consider are also the same — curing time, ease of mixing, ease of application, etc.

The best patching compounds on the market today are 100-percent-solids, epoxy-based formulations. With compressive strengths three to five times greater than concrete, these room-temperature-curing compounds are the strongest products available, and are particularly useful where the deterioration was the result of greater or more frequent stress than received by other parts of the same floor.

Easily trowel-applied, these non-sagging, non-shrinking products provide excellent resistance to water, oils, solvents, acids and alkalis. Some even bond to wet surfaces. In contrast, water-based compounds, readily available at hardware stores and home centers, have poor compressive strengths and aren’t as durable.

High-traffic areas call for a fast-curing formulation; some repair products cure completely in just three hours.

Preparation of an area to be filled or coated is similar to preparing an entire floor. Some repair compounds require the application of a primer to maximize adhesion.

Conclusion
With careful planning, the correct matching of product with expected use and vigilant upkeep, you can avoid common pitfalls and have a concrete floor that lasts for decades with an attractive, durable finish.

This article appeared in the June/July 2002 issue of MRO Today magazine. Copyright, 2002.

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