Guide to Choosing Epoxy vs. Polished Concrete

Selecting the “best” flooring system for an industrial or commercial project can be quite daunting. Due to the potential size, there might be multiple areas within the building that will require various levels of protection.

Let us begin by defining what protection means. According to Webster, it means “to cover or shield from exposure, injury, damage, or destruction.” When protecting a concrete surface, what you are protecting it from is critical. Is it mechanical or chemical? Each one of these will require a different protection method.

Polished Concrete

Concrete is extremely hard and strong when viewed as a large mass. It can support substantial amounts of weight with ease. But being hard and strong does not mean it is highly abrasion resistant. Looking at the surface of the concrete floor, you will notice it is not perfectly smooth. As traffic moves across the floor, the micro-high spots at the surface start to break away. As time goes on, more of the concrete erodes producing a rough wear surface. This is where polishing the surface will help increase the abrasion resistance.

Both foot and vehicle traffic can be highly abrasive. Walking or rolling over the same spot repeatedly will cause the cement paste to break down. Once polished, you have removed the weak peaks. It is difficult to erode a polished surface because it is so smooth and uniform.

When polishing, you first grind the weak high points from the surface creating a smooth, uniform wear surface. As you work your way up in diamond grit size (finer), the surface gets smoother. It is like sanding wood, starting with a coarse grit, and ending with a fine.

Although the abrasion resistance is particularly good with a polished surface, the chemical resistance is marginal. The protective guard applied to a polished surface is very thin offering minimal protection against chemical attack. Organic acids such as vinegar, red wine, and citrus juices could damage the floor even thou having a protective guard applied.

If the appearance of the chosen system has an impact on the flooring decision. When polishing you have options. The depth of the cut will decide the aggregate exposure. Throughout the US, the natural aggregate could be limestone, white or black granite, quartz, limestone, or river rock. These will all have a different appearance once exposed. An extremely durable and decorative floor system can be produced by adding integral color to the concrete. Applying dyes during the polishing process will also add color. This is a way to incorporate a polished concrete floor into a design scheme.

Epoxy (Resinous) Flooring

The term “Epoxy” often describes a resinous flooring system. Not all resin-based floor systems are epoxy. It could be polyurethane, polyurea, or urethane cement. There are many resin formulation types to select from.

If you have a chemical-rich environment, selecting a system that develops a protective surface film might be an excellent choice for your scenario. The resin type is based on what chemical you are protecting the concrete from. Urethanes, such as DiamaPro® UV-HS Plus, are great at protecting concrete from acids, oils, fuels, and all foodstuffs. Urethane cement is ideal for commercial kitchens with deep fryers.

The appearance of the cured system might be a critical factor in the selection process. Using a resinous system the color choice is very wide. Designing an interior space, when using an epoxy-type floor system, is extremely easy.

Epoxy systems can be costly. You need to weigh the cost against what you will end up with. In a beauty salon, the floor can be brighter and more vibrant than in a doctor’s office lobby. The choice includes metallic systems that show multiple colors that flow throughout the floor. For a more industrial look, a solid color pallet is available. All these variations come at a price.

The installation of these systems can be time-consuming. Surface preparation, application, and waiting for it to cure can put the area out of commission. There are systems that reduce the downtime but might add to the cost.

Cost Analysis

When comparing the cost of each system, (polish and epoxy) they have commonalities. All existing floor coverings need to be removed down to clean concrete. If the floor requires repair for one, it will also need it for the other. The surface preparation equipment is also similar. The surface preparation steps for polished concrete are the same as those recommended for installing a resinous system.

Cost Factors

Polished Concrete

• When polishing a concrete floor, some factors need to be determined before a cost can be figured out. The condition of the current floor, how much coarse aggregate is to be shown, and what level of gloss is needed.
• The depth of cut (aggregate exposure) step will take the most time and use the most expensive tooling.
• The higher in grit you go, the less expensive the toiling will be and the faster each step will be.
• During the polishing process, chemicals are used. Although the cost per square foot will be low, they are still a cost.
• Time is money to an owner. The longer the business or owner is not able to use their floor, the greater the loss of revenue. Polishing a floor will take time but once finished polishing, the owner will be able to use the floor.

Epoxy (resinous) Flooring.

• When selecting a resinous system, knowing the chemical will direct you to the resin to use.
• Epoxies and other resinous systems have a range of chemical resistance they will provide.
• The more chemical resistant a system is, the more it will cost.
• The system will dictate the final thickness. Some systems are thin mil (2-10 mil), and others can be as thick as 3/8”. The thicker, the higher the cost for material and installation.
• Systems will require the facility to be completely closed during and after the installation until fully cured. The curing time can be as much as 3-7 days.
• Wet and curing resins can produce a pungent odor.
• The off-gassing odor can absorb in too soft materials such as carpet, chair cushions, window, and wall coverings. It can take time for the odor to dissipate.

Resinous Types

• Epoxy
  • Epoxies can be extremely hard once cured and bond well to a well-prepared concrete surface.
  • Pigment can be added to match a wide variety of colors.
  • They can be produced in 100% solids, waterborne, and solvent-borne formulations.
  • Small aggregate can be added producing a durable trowel grade mortar.
  • Depending on the formulation, the cure time can be long which increases the return to service time.
• Polyaspartic
  • Polyaspartic comes in a multitude of colors.
  • They bond to a prepared concrete surface.
  • Depending on the formulation, the set times will vary.
  • The faster the cure, the higher the cost.
  • There might be a strong odor.
• Urethane
  • Urethanes are normally the top (final) coat of a system.
  • They can go directly onto concrete.
  • They come in 100% solids, waterborne, moisture cure, and solvent-borne formulations.
  • They can have a strong odor and take time to reach full cure.
• DiamaPro® UV-HS Plus
  • DiamaPro UV-HS Plus is an aliphatic urethane.
  • It is a clear topcoat.
  • No primer needed.
  • It has minimal odor in a wet state and has no odor once cured.
  • Cured using high-intensity ultraviolet light.
  • Once the light passes over the wet material it cures.
  • It has a fast return to service.

Project Types

• Warehouse
  • Polished concrete is impact-resistant, easy to clean, and easy to refurbish.
• Showroom
  • Depending on the design of the space, polished concrete or an epoxy system can work. They both can add an architectural flair while still being protective.
• Lobby
  • Depending on the design of the space, polished concrete or an epoxy system can work. They both can add an architectural flair while still being protective.
• Restaurant
  • Depending on the design of the space, polished concrete or an epoxy system can work. They both can add an architectural flair while still being protective.
  • In the food prep area, resinous flooring is most desirable. Urethane cement is the typical choice.
• Industrial Facility
  • If there are no chemicals to attack the floor, polished concrete could be the solution. If there are chemicals involved, select a resinous system based on the chemical and use.
• Food Processing
  • An epoxy resinous system is typically in this environment.
  • They need impact resistance from heavy food carts with hard wheels.
  • When washing down the equipment, harsh chemicals are used.
• Fire Station
  • This could depend on the budget they have to work with.
  • Polished concrete will be at a lower cost than the proper resinous system.
  • Heavy truck wheels may negatively affect a thin mil coating.
• Correctional Facility
  • Unless they are concerned with bodily fluids, polished concrete can be a suitable selection.
  • It is extremely durable and will hold up well underfoot traffic.
  • It is easy to clean and takes little experience if provided with the correct maintenance system.
  • With bodily fluids, a coating to protect the concrete will work the best.

Maintenance

Maintenance is not only sweeping the floor once a week. Maintaining the floor entails removing any contaminants that could damage the floor or reducing potential safety hazards that could lead to slip-fall accidents. With all flooring systems, picking up spilled liquids should be done as quickly as possible.

• Polished Concrete
  • Remove all spills as they happen.
  • Remove all abrasives (sand) daily.
  • With an auto scrubber fitted with the correct diamond-impregnated pad and clean water, clean the floor nightly.
  • Depending on the amount of traffic, the system will appear to lose its gloss. With the auto scrubber fitted with the proper diamond-impregnated pad and a cleaner such as DiamaPro® Diama-Clean, periodically perform a deep clean. This will remove any contamination that might have been difficult to remove during the nightly regimen.
  • After an extended period, the floor will need to be restored. This is a bit more aggressive than a deep clean. Multiple grit diamond-impregnated pads need to be used to bring back the original gloss. It’s all performed with an auto scrubber but in multiple steps.

• Epoxy Resinous Flooring
  • Remove all spills as they happen.
  • Remove all abrasives (sand) daily.
  • With an auto scrubber fitted with the correct pad and a cleaner such as DiamaPro® Diama-Clean, clean the floor nightly.
  • Depending on the amount of traffic, the system will appear to lose its gloss. With the auto scrubber fitted with the proper pad and a cleaner such as DiamaPro® Diama-Clean, periodically perform a deep clean. This will remove any contamination that might have been difficult to remove during the nightly regimen.

Conclusion

Once the floor is evaluated, a proper solution can be selected, but there is no one clear-cut system that will work in every situation. Abuse, chemical attack, downtime, and service life all affect your choice. It is important to understand your needs. Starting with performance and then with appearance. Just because it looks good does not mean it will perform up to your requirements.

Niagara Machine has customer service and sales representatives throughout the country to help guide you through the selection process. Each representative has extensive knowledge in concrete protection whether it be abrasion or chemical attack, they will be a tremendous resource. When choosing epoxy vs. polished concrete, don’t hesitate to contact Niagara Machine for help!