Polyurea & Polyaspartic Coatings

There are several categories of 2-component concrete coatings available today: epoxies, polyurethanes, and polyurea-polyaspartics. All are readily available to contractors that specialize in concrete coatings. But it’s the polyureas and polyaspartics that have created the biggest stir in the coatings industry.

Why? Because these quick-cure coatings are being mass-marketed in “1-day coating systems”…to their customer’s detriment.

In this article, we’ll explain the differences between various concrete coating products, including epoxies, polyurea and polyaspartics, divulging advantages and drawbacks of each. We’ll also explain why “1-day” coating systems, which sound so attractive to customers at first glance, should be avoided wherever possible.

What are Polyurea Coatings?

Pure polyureas are 2-component concrete coatings. That is to say, they have a Part A component and a Part B component that need to be mixed together to initiate a chemical reaction. The 2-component property is typical of all coating types (epoxies, polyurethanes and polyurea-polyaspartics). But what make a polyurea distinct is the rate at which it cures once its Part A and Part B are mixed. The cure rate is extremely fast…polyureas cure in seconds!

They cure so fast, in fact, that specialized equipment called portable reactors are typically required to apply these coatings to substrates. This is great when applying pure polyureas to truck beds, heavy machinery, etc., with a portable sprayer. But if you want to apply these coatings to concrete (like garage floors) using a standard roller or squeegee, then the excessively quick-cure property becomes a problem.

The polyurea cures before you have time to roll it out!

Cue the Polyaspartic Coating

To make these fast-cure coatings a little more user-friendly (so they can be applied with rollers), chemists needed to slow the cure rate down a bit. So, they created what’s called a polyaspartic. A polyaspartic is a chemically modified polyurea (it’s called an aliphatic polyurea) that has a slowed-down cure rate. It still cures quickly, relative to other products like epoxies and polyurethanes, but its slower set time allows application with rollers and squeegees…which means no special equipment is needed.

So, whatever your “1-day” contractor is claiming during their sales pitch, a polyaspartic and polyurea are pretty much the same thing…one is just a slowed-down version of the other. Henceforth, we’ll just refer to them as “polyurea-polyaspartics” to imply that, in fact, they are one-and-the-same.

Benefits of Polyurea Polyaspartic Coatings

These products have lots of upsides, aside from their relatively fast cure rates. They offer extreme flexibility, low to no VOCs (so they can be used safely indoors), abrasion, impact, scratch and stain resistance…and extremely high chemical and UV resistance.

So, these products are excellent coatings for high-traffic, high-impact areas like garages, commercial spaces, and such.

Disadvantages of Polyurea-Polyaspartic Coatings

The shortfall with polyurea-polyaspartic coatings, brilliant as they are, is that they aren’t spec’d for direct-to-concrete application, meaning they shouldn’t be used direct to raw concrete…especially where the concrete exhibits medium to high moisture content (as determined by a moisture meter).

Why? Because polyurea-polyaspartics don’t penetrate concrete well and their chemistry only allows them to be applied thinly. So, they are very susceptible to the pressures that build up in concrete due to moisture over time – called hydrostatic pressure. Concrete is porous and moisture wicks up through the pores in a process known as moisture-vapor transmission (MVT). Over time, a (hydrostatic) pressure builds and pushes up against the applied “primer” coat.

This might not be a problem under very dry concrete conditions. But many “1-day” contractors don’t even measure concrete moisture! And even if they do, the readings reflect a point-in-time. Low concrete moisture today, doesn’t mean it will remain so over time.

Knowing this, why would any contractor take this chance and apply a polyurea-polyaspartic as the primer coat?

The Problem with “1-Day” Coating Systems

The answer to the question? It’s profitable! Thin 1-day polyurea-polyaspartic coating systems use less product and only one day of labor!

Great for the contractor… not so great for the customer!

“1-day” systems consist of a thin polyurea-polyaspartic primer coat, a layer of flakes broadcast into the thin primer, and a single clear polyurea-polyaspartic topcoat. Since a polyurea-polyaspartic base coat doesn’t penetrate the concrete well, it simply can’t handle extreme upward hydrostatic pressures – and so it peels (delaminates) over time. And delamination is one of the leading causes of concrete failure!

THIS IS WHY “1-DAY POLYUREA-POLYASPARTIC” CONTRACTORS NEVER WARRANT “MOISTURE-RELATED ISSUES”. Their warranty exclusion section states as much. Here’s an example:

“…excluded from the floor coating warranty…peeling or delamination caused by moisture underneath the slab on which the floor coating was installed.”

Photo 1: A “1-day” polyurea-polyaspartic coating system that has peeled up like wallpaper! These coating systems don’t do well when applied to concrete with moisture (because polyurea-polyaspartics don’t penetrate concrete very well).

 Using a quick-curing polyurea-polyaspartic direct-to-concrete allows the contractor to get the job done in 1 day, but the risk of delamination over time is high. This is exactly why “1-day” contractors don’t warrant for “moisture-related issues”.

All Coating Types Have Advantages & Disadvantages

Remember earlier in this article, I said there are three coating types – epoxies, polyurethanes and polyurea-polyaspartics. Even though polyurea-polyaspartic coating types are excellent products, as I’ve discussed, they have one major issue: they’re poor primers. Epoxy coating types are the reverse. They can be applied thickly (they’re called “high-build” coatings) and penetrate concrete deeply…so moisture-mitigating epoxies are excellent as primer (direct-to-concrete) coats. However, epoxies amber or fade when exposed to sunlight (UV light) and can stain and “lift’ from hot tires.

In other words, a moisture-mitigating epoxy is a great primer…but a lousy topcoat. Conversely. a polyurea-polyaspartic is a great topcoat…but a lousy primer coat.

So why not construct the optimum, longest-lasting coating system that uses the best properties of both coating types? (1-day contractors don’t like this option because the slower-curing epoxy primer forces the installation duration from 1 day to 2 days).

Building the Best Coating System

But that’s just what all contractors should do. Take the extra day to build the best possible coating system for your customer…one that’s fully warranted against moisture (and staining) unlike “1-day” polyurea-polyaspartic systems.

The best coating system for your home or commercial space is the one where the contractor picks the best properties of each coating type. The coating types used to coat a patio, basement, kitchen or garage floor shouldn’t be the same – the selected coatings must reflect the needs of your unique concrete space.

For instance, for the most durable garage floor coating system uses a 100%-solids moisture-mitigating epoxy as the primer coat (high-build epoxies are more resilient to high hydrostatic pressures)…and uses a high-quality, fast-curing polyurea-polyaspartic as the topcoats only (to provide the required UV and stain-resistance that an epoxy can’t).

I specified “‘high-quality” polyurea-polyaspartic because most “1-day” outfits aren’t using 100%-solids polyurea-polyaspartics as the topcoat (the solids content is lower). Lower-quality polyaspartics don’t provide the same degree of “cross-linking” and so they don’t protect against hot-tire transfer (also called plasticizer migration). Here’s a sample warranty exclusion from “1-day” contractor:

“…plasticizers used in the tire industry to provide more traction can leach out of the tire. While polyaspartic coatings resist tire staining better than other coatings, we cannot prevent this from occurring.”

Yes, you can! if you use a quality 100%-solids (3:2 ratio) polyaspartic topcoat.

“1-day polyurea-polyaspartic”’ contractors understand all of this, but the call of a low-cost/low-labor “1-day” system is strong, and the workaround easy. Offer the customer a (limited) lifetime warranty that doesn’t warrant for “moisture-related issues” and staining. If your 1-day coating peels (or stains due to hot-tire transfer), just invoke the warranty exclusion!

If “1-day” contractors were confident in their coating products and application process, why wouldn’t they provide a full warranty for moisture-related issues?

We’re Expert Installers of Concrete Coatings

At Garage Floor Coatings of the Front Range, we have all coating types in our tool box…and we use the best properties of each to create the longest-lasting coating systems for your unique space. We have quality polyurea-polyaspartic coatings, so we could install “1-day” systems! But we don’t. We’re a 2-day installer…providing quality over speed. Our typical garage floor coating system uses a moisture-mitigating 100%-solids epoxy as the primer coat, a broadcast of your selected flake blend, and 2 coats (not 1) of our 100%-solids clear polyaspartic. A 4-layered system over 35 mils in thickness!

Don’t play Russian Roulette with your time and money.

Like all coating types, polyurea-polyaspartics are only excellent coatings when used the way they were meant to be used.