Designing for Custom Concrete Flooring
During the design phase of a project, there are many design options available when planning for custom concrete. Think of concrete flooring as a blank slate onto which you can create a statement and enhance the decor. Below are different concrete flooring treatments to consider when planning your next project.
The Beauty and Versatility of Decorative Concrete Overlays
Microtoppings, polished overlays … Decorative overlay” is a term that covers a wide variety of products and systems designed to provide a decorative finish over an existing substrate. Proper preparation of the floor surface is critical to ensure a concrete overlay will take hold. A decorative concrete overlay can be very thin, 1/16th of an inch or up to 1/2 an inch and is typically applied in two or more coats by magic trowel, hand-trowel, brush, roller spray or notched squeegee and back roll.
Two popular types of decorative overlays are Microtoppings and Polished Overlays.
Microtoppings
Microtoppings, or thin-section overlays, are the most popular type of overlay on the market. There is good reason for the popularity. Microtoppings offer a wide range of decorative options.
- Microtoppings offer the most variation in color and finishes.
- The ability to manipulate the look of a microtopping creates a wide range of design options.
- Microtoppings are strong. Some microtopping systems can reach 3000 psi, while higher-end interior systems used in high-traffic situations can top 6000 psi.
Polished Overlays
The majority of concrete slabs can be polished. Existing slabs often have imperfections such as tile grout lines, patch marks from framing braces or carpet tack strips, or even larger areas of the slab that have that have been torn out and replaced in making major plumbing repairs. Polished overlays give concrete the brilliant gloss but without the imperfections of the existing slab showing through.
Understanding the Levels of Aggregate Exposure
While the polish finish is the end-game for custom concrete applications, aggregate exposure in custom concrete flooring can add a dimension of beauty and interest to the finished product.
Concrete aggregate exposure is popular with architects looking for a flooring option that offers design flexibility at a lower cost than terrazzo. The polishing process usually includes grinding down the concrete surface to reveal different levels of aggregate within the concrete or the addition of decorative aggregates, such as recycled glass, landscaping stone, and others, seeded into the surface for decorative purposes. Depending on the diamond grit used to prep a polished a concrete floor, different levels of aggregate exposure can be achieved.
CLASS | NAME | APPROX SURFACE CUT DEPTH |
APPEARANCE | EXAMPLE |
---|---|---|---|---|
A | Cream | Very little | Minimal exposure of fine aggregates or sands. A high level of flatness and floor levelness is required to maintain a uniform appearance. | |
B | Fine aggregate (Salt and Pepper finish) | 1/16 inch | Fine aggregate exposure. Cut depth of ~1/16 of an inch exposes fines and sand; no larger aggregate seen. | |
C | Medium aggregate | 1/8 inch | Medium aggregate exposure with little or no large aggregate exposure at random locations. Cut depth of ~1/8 of an inch exposes small to medium aggregate. All surface paste is removed. | |
D | Large aggregate | 1/4 inch | Large aggregate with little or no fine aggregate exposure. Cut depth of ~1/4 of an inch, exposes coarse aggregate similar in appearance to terrazzo. | |
— | Random Exposure | 1/4 inch | Cut depth of ~1/4 of an inch, exposes aggregate variations. |
Choosing the Level of Polished Concrete
Knowing the different levels of polished concrete will help your clients visualize the finished product. Below is a polished concrete spectrum resource to help you determine the best outcome for your client.
200 Industrial Grit Polish

400 Grit Polish

800 Grit Polish

Grind, Stain and Seal

Grind and Seal

Epoxy Coatings Can Be Beautiful as well as Tough
Epoxy is no longer just a treatment for garage floors. Restorative, functional and decorative are not mutually exclusive. You can have it all with the proper research and selection upfront.
When specifying epoxy coatings, it’s best that decision-makers – including architects, owners and facility managers – consult an experienced and knowledgeable flooring professional throughout the design process to ensure the proper floor is selected. Provisions for flooring mock-ups (that will show thickness, color and texture), long-term maintenance and repair needs, should be incorporated into the specifications.
Environment Design and Selection Criteria
There are several environmental issues that may be overlooked when specifying a fluid applied polymer floor system. While they may not contribute to the function of the finished floor, they are nonetheless important to the successful installation, appearance and life expectancy of the system, and ultimately, the owner’s satisfaction.
- Aesthetics – The finished appearance of the flooring system can sometimes be more important to an owner/end user than the function of the floor itself. As the specifier/designer, it’s important to understand that functionality and aesthetics are not mutually exclusive. With all of the fluid applied flooring options available in the marketplace, the required functionality can be achieved with a variety of decorative options and textures.
- UV Stability – Polyurethanes are for the most part UV-stable while epoxies are not UV-stable. UV inhibitors are available as an additive. They can be incorporated into epoxies for interior use and should always be incorporated into the epoxy and the polyurethanes on exterior applications. Interiors that will be subjected to bright sunlight should also receive consideration for UV inhibitors.
- Anti-Microbial – Additives are available to control germs and pathogens. These additives should always be considered when installing polymer flooring in areas such as medical facilities, bathrooms, biomedical facilities or any other area of concern.
- Low VOC/No VOC – Many of the solvent-based systems and resins will have inherent odors. In occupied areas or areas where food is being prepared or packaged, the installation of polymer flooring with low VOC, low odor or no VOC should be factored into the selection.
- Electrostatic Dissipative (ESD)/Conductive Coatings– There are several situations – including those in fuel storage areas, electronics manufacturing, explosives manufacturing, pharmaceutical manufacturing and clean rooms, to mention a few – that may need specialized flooring that is designed to prevent electrostatic damage to products and equipment, limit the ability of personnel to build up a charge on their person and quickly remove a charge on a person or equipment.
- Slip-Resistance– This should always be factored into the finished floor. The texture of the final finish coat and various aggregates such as silica sand, bleached aluminum oxide and glass beads are some of the methods and materials available. In addition, many decorative and functional systems have slip resistance built in, such as color quartz floors. Slip resistance requirements are defined by OSHA and ADA standards.
- Budget – While cost is important, it must be understood that installing a floor based strictly on the lowest cost could lead to repeated repairs down the road, or in the worst case, complete removal of the failing floor and re-installation of a new system.
Form and Function
There is a wide variety of polymers that offer both performance and decorative options including epoxy, polyurethane, polyaspartics, urethane mortars and acrylics. Each one of these materials possess different characteristics that will affect the final performance and aesthetics of any system.