Polyurea & Polyaspartic Coatings

Epoxies, polyurethanes, polyureas and polyaspartics are all concrete coating types currently on the market. However, it’s the two latter types of coatings, polyureas and polyaspartics, that have caused such a stir in the concrete coatings industry. In fact, installers like these coatings a lot…the fast-cure capability of polyurea and polyaspartic coatings is often promised as the solution to all of your concrete coating woes and has led to the mass-marketing of ‘1-day coating’ systems. It’s also created confusion for homeowners.

In this article, we’ll try to explain the differences in coating products and show that each has great benefits…and great weaknesses.

What are Polyurea and Polyaspartic Coatings?

Pure polyureas are 2-component concrete coatings (Part A and Part B) that, when mixed, possess extremely fast cure rates (they cure in seconds). So fast, in fact, that specialized equipment like a portable reactor is required to apply them. Although this fast cure rate is a good thing when polyureas are applied to truck beds, roofs, or heavy machinery, for example, it’s not such a great thing when trying to apply polyureas to concrete with rollers!

So, what’s a polyaspartic? A polyaspartic is a polyurea that has been chemically modified to slow down its cure rate (…it’s an “aliphatic polyurea”). The slowed down cure rate allows trained applicators to apply polyaspartics using rollers and squeegees…specialized equipment isn’t required!

During the sales pitch of your bidding contractor, you’ll likely hear that polyureas are better than polyaspartics…or vice versa. But the reality is, your contractor is using a slowed down version of a pure polyurea. From this point forward, we’ll refer to these coatings as “polyurea-polyaspartics” to infer that they really are one-and-the-same!

Benefits of Polyurea Polyaspartic Coatings

There are many advantages to using polyurea-polyaspartic coatings. They can cure very quickly relative to other coating types…even at low and high temperatures. These high gloss coatings provide high flexibility, along with abrasion, impact, scratch and stain resistance, and extreme chemical and UV resistance. They also have no to low volatile organic compounds (VOCs) so they are safe to use indoors and out.

And, under very low concrete moisture conditions, you can apply a polyurea-polyaspartic coating system in 1 day with a ‘return-to-use’ the following day. But, more on this later.

Disadvantages of Polyurea-Polyaspartic Coatings

As fantastic as polyurea-polyaspartic coatings are, they have one major flaw – they simply aren’t spec’d for direct-to-concrete application. That is to say, they shouldn’t be used as a primer coat applied directly to raw concrete, especially in medium to high concrete moisture conditions (as can only be determined using a moisture meter).

Why? Because polyurea-polyaspartics don’t penetrate concrete well (like a moisture-mitigating epoxy can) and can only be applied as a thin coat (unlike an epoxy which can be applied thickly). Polyurea-polyaspartics simply don’t mitigate well for moisture.

Does concrete have moisture? Yes, it does. Moisture wicks up through porous concrete in a process known as moisture-vapor transmission (MVT). And as the moisture pushes upwards, a (hydrostatic) pressure builds, forcing up against the primer coat. Under very dry concrete conditions, this may not be an issue, but why would any contractor take the chance?

The Problem with “1-Day” Coating Systems

“1-day” coating systems consist of a polyurea-polyaspartic base (primer) coat, a layer of flakes broadcast into the thin primer coat, and a single clear polyurea-polyaspartic topcoat. Because the wafer-thin polyurea-polyaspartic primer coat doesn’t penetrate the concrete well, it simply can’t handle high hydrostatic pressures, and as a result, easily peels (delaminates) over time. And delamination is one of the main reasons for concrete failure…which is precisely why “1-day polyurea” contractors won’t warrant their coating systems against ‘moisture-related issues’.

The following photos depict a real “1-day” coating system that failed. Note the way the coating has peeled away  in sheets from the concrete substrate!

Then Why Install This Type of Flooring?

Applying a polyurea-polyaspartic, first as the primer coat and then as the clear top coat, makes it possible for contractors to advertise that they can install concrete coatings in 1-‘day’ (because polyurea–polyaspartics cure quickly). But if the presence of moisture in the concrete is the root cause of coating system failures, why would a contractor take the chance selling “1-day” polyurea-polyaspartic flooring at all?

Because its profitable! 1‑day polyurea-polyaspartic coating systems require less product (one primer coat and one top coat)…and only 1 day of labor! Great for the contractor…not so great for the customer.

All Coating Types Have Advantages & Disadvantages

As you recall from the beginning of this article, there are different coating types – epoxies, polyurethanes and polyurea-polyaspartics. Though polyurea-polyaspartic coating types are excellent products, we have observed that they do indeed have a major drawback: they’re lousy primers. Epoxy and polyurethane coatings can also be great products…but they also have drawbacks. Epoxies, for instance, ‘amber’ or ‘fade’ when subjected to sunlight (UV light) and are prone to staining and “tire lift”. Applying an epoxy as a top coat to UV-exposed concrete would be a bad decision. Yet moisture-mitigating epoxies are ‘high-build’ coatings that deeply penetrate concrete…so they’re great primers!

So, a moisture-mitigating epoxy is a great primer, but lousy topcoat, and a polyurea-polyaspartic is a great topcoat, but lousy primer coat. So why not use the best properties of each coating type to build the perfect, long-lasting coating system…that doesn’t need a warranty exclusion for moisture?

Building the Best Coating System

All coating types – including polyurea-polyaspartic coatings – have strengths and weaknesses. The best coating system requires the contractor select the best properties of each coating type and use them for your unique space to be coated!

For example, the best coating systems for garages use a 100%-solids moisture-mitigating epoxy as the primer coat (these high-build primers have excellent resistance to hydrostatic pressures)…and a quality fast-cure polyurea-polyaspartic coating as the topcoats (because they provide the UV and stain-resistance). I specifically stated “high-quality” polyurea-polyaspartic, because lower quality versions used by several “1-day” companies do not protect against hot-tire transfer (also called plasticizer migration). These companies actually suggest that you park your car on vehicle pads!

In Conclusion

In short, for garage floors that frequently exhibit medium to high moisture in the concrete and are exposed to UV light and potential chemical staining (from automotive fluids), the ideal coating system uses a 100%-solids moisture-mitigating epoxy as the primer coat and a polyurea-polyaspartic as the clear top coat(s).

‘1-day polyurea’ contractors understand this, but the call of a low-cost/low-labour “1-day” system is strong, and the workaround easy: simply give the customer – who doesn’t read the fine print – a (limited) lifetime warranty that includes warrant exclusions to “moisture-related issues’ (like hydrostatic pressure). If your 1-day coating peels – you guessed it – just invoke the warranty exclusion!

These warranties expose the hand of every “1-day” contractor! If they were confident in their coating products and application process, then why not provide a full warranty for moisture-related issues?

We are Expert Installers of Concrete Coatings

At Garage Floor Coatings of Maryland, 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.

In this over-saturated, concrete coatings market, Garage Floor Coatings of Maryland has seen countless “1-day” contractors and DIY applicators apply sub-standard concrete coatings. It doesn’t have to be that way.

We only install industrial-grade concrete flooring. We take 2 days to install and we’ll never apply a polyurea-polyaspartic direct-to-concrete. We won’t play Russian Roulette with your money.

Like most things in life, quality takes a little more time.