Common Concrete Surface Finishes

Concrete is one of the most common flooring substrates used in commercial and industrial buildings. Its durability, performance, and lifespan can be virtually unequalled, if it is:

• Poured and placed correctly, with the right concrete mix and curing process for the situation
• Properly finished for the specific type of facility
• Cleaned regularly and well-maintained

Leveling the Surface

Typically, a concrete finish is smooth. Smoothening the concrete is accomplished through a four-step process:

• • Step 1 – Immediately after the concrete is poured into the forms, a screed is used. A screed may be made of a long, straight piece of metal or wood (e.g., a long 2 x 4), and it is pulled back and forth across the forms, sometimes in a sawing motion, to level the concrete.

• • Step 2 – Further smoothening is done using either a trowel or a float. They are similar in their action and are available as manual or power (mechanical) tools. For large commercial or industrial floors, walk-behind and/or riding power trowels are used. Both have large blades that resemble a fan that is situated face-down on the wet concrete surface. The blades typically have a protective cage for enhanced safety.

• • Step 3 – Next, an edging tool is used to create smooth, level edges and corners immediately adjacent to the form. It is similar to a trowel but has one side curved, to fit down, between the form and the slab, smoothening the edges in spaces where the trowel does not fit. The edging tool may also be used to create certain types of floor joints. Engineers specify various concrete joints to ensure the slab is separated from the existing structure, as well as to direct and minimize cracking during the inevitable settling of new slabs. Special elastomeric joint treatments are frequently used to fill and bridge construction joints, while still accommodating some movement.

• Step 4 – The final step in working the wet slab is often to create what is called a “broom finish”. As the name implies, this involves dragging a broom across the smooth surface of the concrete. A completely smooth surface can be dangerous, as it provides little traction. A broom finish results in small ridges that offer pedestrians a degree of slip-resistance and provide tires with better grip.

After these steps are accomplished, diverse curing techniques and surface treatments are available.

Walk-behind power trowel being used to smoothen a concrete surface

Finishes and Coatings for Concrete Substrates

Concrete floor finishes and coatings are not “one size fits all.” There are myriad flooring systems available to meet the needs of virtually any environment and facility operation. Innumerable products and methods, including everything from curing compounds, light duty spray-on sealers, and concrete stamping, to concrete polishing, staining and high performance coating systems are available. As the category offering some of the best lifecycle value, industrial high performance coating systems will be discussed below.

Five of the most frequently specified high performance floor coatings are:

• Epoxy flooring
• Urethane topcoats
• Cementitious urethane mortars
• Polyaspartic finishes
• Vinyl ester coating systems

Epoxies

Epoxies have long been one of the most utilized general service coatings for concrete floors. They are highly durable, abrasion- and chemical-resistant, and offer exceptional durability. Today’s more color-stable epoxy systems are also zero V.O.C. and perform admirably in the face of heavy pedestrian, cart and forklift traffic. Quality manufacturers offer many custom options, such as antimicrobials that inhibit the growth of pathogens, primers and underlayments that mitigate moisture vapor transmission, as well as various levels of slip resistance. Additionally, epoxy floor systems never need buffing or polishing, so maintenance efforts and associated costs are reduced.

Available in a vast array of standard and custom colors, nearly any floor design can be realized, such as geometric patterns, freehand drawn shapes, safety and traffic lanes, as well as embedded logos, images and wayfinding messages.

Expert application of FloroThane High Performance Urethane Topcoat in Light Grey by Epoxy, Inc. of FL.

Urethane Topcoats

High performance, thin film aliphatic urethanes are frequently utilized as UV-stable topcoats over many general service epoxy coating systems, offering additional protection and longevity to the floor finish. Many provide extra resistance to:

• Harsh chemicals, oils, solvents and grease
• Abrasions and scratches
• UV exposure
• Stains and discoloration

Other benefits include:

• The ability to withstand exposure to slightly higher temperatures

• Good flexural and tensile strength
• Ultra-high solids and low V.O.C.’s

Thin film urethanes are generally available as Clear finishes that can be field-tinted with compatible pigments by the same manufacturer.

Cementitious Urethane Mortars

Cementitious urethane mortars are called such, because they contain Portland cement. This gives them the property of expanding and contracting at a rate similar to the concrete substrate. Because of this, cementitious urethane mortars have excellent thermal shock resistance, making them ideal for the food and beverage processing industry, where extreme temperature swings and cycling can be the norm.

Cementitious urethane mortar systems also perform admirably in environments where the floors are exposed to:

• Extreme pH (highly acidic or alkaline) substances
• Ongoing wet or moist conditions
• Moisture vapor transmission

These systems are often available:

• In several formulations that can be applied at different thicknesses
• In a range of solid colors, with monolithic colored topcoats
• In hybrid systems, incorporating a nearly unlimited selection of decorative flake blends or colored quartz toppings
• With customizable slip-resistance, installed per the building owner’s specifications

The tenacious bond, low odor, expeditious cure and other unique properties of urethane mortars make them ideal for many floor coating applications.

Polyaspartic Coatings

Polyaspartic coatings are among the newest resin technologies that have come to market of late. They offer good abrasion- and chemical-resistance, and like urethanes, are tolerant of slightly higher temperatures than general service epoxies. The primary benefit of polyaspartics is their exceptionally fast cure. Depending on the facility and environmental conditions, full cure can often be achieved within two hours of the final coat application, making it an excellent option for facilities that run 24/7.

Vinyl Esters

Vinyl esters provide extreme chemical and corrosion resistance, as well as tolerance for exposure to higher temperatures. Often utilized as primary and secondary containment coatings, they provide excellent protection in many industrial settings where other finishes would quickly break down. By isolating toxic or otherwise deleterious substances on their surface, vinyl esters enable proper clean up and disposal of hazardous liquids that could otherwise contaminate the building and surrounding environment.

Call the Florock Experts

Our highly experienced team of professionals can help you sort out the many concrete coating and finishing options and choose the best flooring for your facility.