Differences Between Epoxy, Polyurea and Polyaspartic Coatings

Concrete floor coatings come under many names. You may have heard of “epoxy” or “polyurethane” coatings. More recently, “polyurea” and “polyaspartic” coatings are part of the lexicon. But what’s the difference between an epoxy, polyurethane, polyurea and polyaspartic? Is one coating type better than the other? And how can you ensure you’re getting a high quality concrete floor coating?

Unfortunately, the market is teeming with garage floor coating companies, and many use home hardware-quality products or sell questionable “1-day systems”. They all claim their products and systems are the best. In this blog, we’ll explain the different coating types and why all coating systems are not alike.

Concrete Coating Product Types

If you’ve done some research, you may have heard about the three main types of floor coating products: (a) epoxy, (b) polyurethane and (c) polyurea-polyaspartic coatings. All three products are 2-component coatings. That is, a “Part A” component is mixed with a “Part B” component in a specific ratio. Each of these floor coating types differs in chemistry and properties to deliver unique desired results.

What’s an Epoxy?

Epoxies are often used as direct-to-concrete “primer coats” but may also be used as color coats given the right substrate conditions (interior installations, for example). They provide deep substrate penetration and are excellent at mitigating moisture. Epoxies do come with drawbacks, however. In the presence of sunlight (UV), epoxies can “amber” or “fade” and are susceptible to staining and tire lift. (So applying an epoxy as the final topcoat to a UV-exposed concrete patio or a garage would be a bad decision). They also possess a short “pot life” (the time during which the epoxy remains in liquid form in its container once mixed)…and can “cook” in the pail. They must be mixed and applied to concrete quickly…the cure rate actually slows once the epoxy is poured out of its mixing container.

But epoxies are the best choice as primer coats…and it has to do with the way they cure.

Epoxies cure by way of an exothermic reaction (reactions that generate heat). The amount of heat generated depends on the thickness of the epoxy mass…a thicker mass retains more heat, causing a faster reaction, producing even more heat. 100%-solids epoxies cure by this chemical process and not by way of solvent evaporation. So, if 4 mils of a 100%-solids epoxy is applied to a substrate, the end coating will be 4 mils thick (a “mil” is a unit of thickness equal to 1/1000 of an inch).

Because of this property, epoxies can be applied thickly and still cure efficiently (they’re “high-build” coatings). This makes them excellent primer coats where concrete moisture is present. Concrete is porous and moisture wicks up through it in a process called moisture-vapor transmission; this moisture can create high hydrostatic pressures over time. Because epoxies provide deep penetration and can be applied thickly, they can resist high hydrostatic pressures and simultaneously bury substrate imperfections.

Our line of epoxy products includes our pigmented 100% Solids MME, 100% Solids Polymer Orange Label and Hydro Polymer products.

What’s a Polyurethane?

Polyurethanes use an older technology and are a blend of urethane resins. Because polyurethanes do not provide the binding strength or millage of an epoxy, they’re not designed to fill defects in concrete and are not designed for direct-to-concrete application…instead, they are applied in thin coats. However, when polyurethanes are applied over an epoxy primer coat, they provide highly durable, user-friendly, UV and stain-resistant flooring.

A major drawback of polyurethanes is that they’re not recommended for garages as topcoats because they’re susceptible to staining by the plasticizers in “new technology” tires. As such, polyurethanes are typically used on exterior patios and in spaces where vehicles are not parked for extended periods.

Our pigmented Poly 3000 and Poly Pro II series of products are examples of this coating type.

What are Polyurea & Polyaspartics?

A polyurea or polyaspartic is a “hybrid” between an epoxy and polyurethane. What’s the difference between the two? A polyurea, often used in industrial and commercial settings to protect surfaces, has an extremely short cure time, but is durable enough to coat roofs, foundations, decks, truck beds, and other surfaces. But “pure” polyureas cure so quickly (in seconds) that specialized application equipment is required.

A polyaspartic is modified polyurea…called an “aliphatic polyurea”…that has been chemically modified to cure slower than a polyurea (…just not as slow as an epoxy). This “Goldilocks” quick, but-not-so-quick curing capability is why polyaspartic coatings are regularly used in the concrete coatings industry (they’re more user-friendly than “pure” polyureas). This and the fact that a polyaspartic provides extreme UV, chemical and impact resistance, makes them excellent choices as garage floor topcoats.

A quality (high solids 3:2) polyaspartic can protect against staining from automotive fluids, hot-tire transfer, bumps, and fading due to sunlight exposure. As such, these products don’t “amber” over time like epoxies when exposed to UV light and don’t stain due to hot-tire transfer. And importantly, polyaspartics cure quickly, allowing for a quick “return to service” and may permit 1-day applications if concrete conditions are suitable.

What are the disadvantages? Polyurea-polyaspartics are not meant to be applied direct-to-concrete (because they can only be applied thinly and don’t properly mitigate for moisture and high hydrostatic pressures). In addition, a polyaspartic has a “pot life” of only 25-30 minutes…and this time decreases as temperature and humidity increase. So polyaspartics are great as pigmented color coats or clear topcoats…but lousy as primer coats, despite what the “1-day” contractors tell you. And because they cure so quickly, they’re only recommended for use by seasoned, well-trained professionals.

Our line of polyaspartic products include our clear 100%-solids Poly Hybrid (3:2) and clear Poly Hybrid Gen II (3:2), as well as our clear LOPH II (1:1) and pigmented Poly Hybrid (1:1).

When to Use What Products?

The reality is that epoxy, polyurethane and polyurea-polyaspartic coatings each possess important advantages and disadvantages. These products are typically used in combinations to produce the most durable flooring for your unique space. Does your concrete exhibit high moisture? Is it exposed to the sun’s UV? Is there a potential for chemical staining? Is it a low-odor indoor or outdoor application? Do you need a fast “return-to-service”?

The answer to these questions will determine which coating products should be used to coat your unique space.

But the type and combination of coating products used must be determined by a professional installer only after assessing your space to be coated. “1-day” contractors that only use a polyurea as the primer coat (bad idea) and polyaspartic as the topcoat are just playing Russian Roulette with your flooring (and their warranty exclusions attest to this).

Understanding the pros and cons of an epoxy, polyurethane, polyurea-polyaspartic, and how to properly use these products in combination, will provide the most durable coating system for your unique space. “Contractors” mass-marketing 1-day installations and DIY kits from your local hardware store don’t take these matters into consideration.

We’re Your Local Expert Installers

Real knowledge and experience in concrete preparation, crack repair, product selection and application technique are too important to forgo. Using inexperienced “contractors” selling 1-day installations or DIY epoxy kits to save money are costly mistakes. More often than not, the result is a poor quality floor coating and a costly redo.

Garage Floor Coatings Rochester NY is an authorized GarageFloorCoating.com flooring specialist using Eco-Corflex Industrial Polymers’ line of coatings. Talk to us about your needs. We’ll be happy to show you our array of stunning full-chip coating systems and colors…and you can be confident you’re hiring a floor coating installation expert.