Coatings Summarized: The Advantage and Disadvantage of using Aspartic, Epoxy or Urethane

When it comes to coatings, it’s easy to get overwhelmed. What coatings should we use for each application? Why don’t we put Epoxies on our sundecks? Why are urethanes not commonplace for interior flooring projects? What the heck is a polyaspartic? Well, we’re here to help.

Let’s start by breaking down some of the key traits of each of these systems.

Polyurethane Coatings

Polyurethanes are inherently flexible, waterproof, crazy durable and offer endless solutions to endless problems. In liquid form, urethanes can look like paint or pancake batter and are typically air cured or need to be catalyzed to cure. Urethanes are an excellent solution for sundecks, especially over wood. Because of the flexibility and the ability to manipulate them to provide UV stability, good quality urethane deck systems (like Flexstone) adhere permanently to plywood or primed concrete and provide a tough rubbery surface that moves with the natural expansion and extraction of the substrate (the surface it’s been applied to).

Urethanes are not limited to the construction industry, odds are you use urethane products regularly and may not even know it. Some of the more common applications include: faux leather clothing products, rain gear and athletic shoes; casings for underwater wiring, it’s what golf balls and airless tires are made of and what insulates your refrigerator. Urethane coatings are used to protect hardwood flooring and the trays in your dishwasher. They’re also a very commonly used adhesive.

polyurethane coatings

While urethanes seem infallible, there is one aspect to be aware of. When coating any surface with trapped moisture (I’m talking to you, concrete), the surface must be treated with a vapor barrier (usually epoxy). Trapped moisture, when heated in the sun wants to evaporate. Because urethanes are so flexible, this can cause blisters to form on the surface. Fortunately, an affordable epoxy primer/sealer applied to the concrete will prevent this from occurring.

epoxy coatings

Epoxy Coatings

Epoxies are a very different beast than their elastic urethane friends. Epoxies are ROCK solid and extremely tough. No flexibility, no cushiness and you won’t find it on the outer liner of your raincoat. Epoxy is typically mixed with a ‘hardening agent’ which catalyzes the curing process and turns it from a liquid state to solid. Epoxies are one of the strongest adhesives out there – so strong in fact, that its used as an adhesive and protective coating in aircrafts, space crafts, and ships.

While its strength and bonding ability is second to none – epoxies do have their limitations. Because they cure to such a solid state, on surfaces that see any sort of movement or flex, epoxies are susceptible to cracking and chipping. Also, epoxies are not UV stable, so on any exterior surfacing you can expect some discoloration and even flaking in some cases. Like my dad, epoxies are as tough as they come, but equally as inflexible.

Polyaspartic Coatings

Polyaspartics are a sensible middle-ground between urethanes and epoxies. Polyaspartic membranes are quickly becoming the most popular coating option for concrete patios on grade, garage floors, and any other floor that is exposed to UV light. Well, as you may have guessed, many polyaspartic coatings are made with aliphatics that provide the coating with UV stability which makes it a great candidate for many exterior applications.

polyaspartic coatings

Polyaspartics fall somewhere between epoxies and urethanes with regard to flexibility. Aesthetically, you likely couldn’t tell a difference between an aspartic or epoxy floor, but aspartics have some flexibility which allows small movements in concrete substrates to happen without the risk of cracking (don’t use them on plywood though, your you’ll see cracks in short order). Sure, it is not as ‘rock solid’ as epoxy or as ‘rubbery’ as urethane – but that middle ground is ideal for your garage floor or exterior walkway. They’re incredibly strong, easy to apply and eloquently fill the gaps between what urethanes and epoxies can do.

Traditionally, all polyaspartics were 2-component systems, like epoxies, however; Flexstone’s FSC Aspartic is the first single-component polyaspartic on the market, making it the easiest floor to install and an ideal solution for the DIY crowd to spruce up their garage floors or exterior walkways.