Last Updated on April 23, 2023 by Ernest Godia
Polyurethane and epoxy are among the most robust coatings for wood and other surfaces. Since they both have their fair share of strengths and limitations, choosing between them can be challenging unless you know the exact features to look for.
The two flooring solutions are polymers with different properties that can make one more suitable for your needs than the other.
This write-up discusses polyurethane vs epoxy coatings for hardwood floors, presenting a detailed look at their similarities and differences.
You will find a concise summary of the best-use scenarios for polyurethane and epoxy coatings to simplify things for you.
What is polyurethane?
Polyurethane is a synthetic polymer or resin compound composed of linked urethane groups. It is a combination of chemical compounds that react to form a liquid plastic or plastic-like substance.
Polyurethane, abbreviated as PU or PUR, is sometimes described as liquid plastic because of its resinous property.
Most polyurethane types are thermosetting polymers, so heat does not melt them once cured on a surface.
Polyurethane comes in various sheen levels—gloss, semi-gloss, satin, and matte. This wide range of sheens allows you to select what best suits your needs.
Polyurethane pros and cons
Here is a discussion of the benefits and limitations of polyurethane to keep in mind when selecting a flooring solution.
Pros of polyurethane
- It is highly resistant to extreme temperature fluctuations, chemicals, and abrasion.
- Polyurethane is flexible and highly durable.
- It is resistant to UV damage.
- It retains its gloss well and for a long time
- It retains its color over time
- It has good waterproofing qualities
Cons of polyurethane
- Very sensitive to humidity, which can affect its ability to cure properly.
- Prone to gouging, not as resistant to heavy industry traffic as epoxy surfaces.
What is epoxy?
Epoxy is a thermosetting polymer resin used as a coating mainly for floors. While epoxy is typically used to seal concrete floors, it also adheres well to hardwood floors, making it an excellent sealant.
Epoxy resin is available in three different formulations, namely solvent-based, water-based, and 100-percent solids.
The three different formulations have varying degrees of thickness of the coating and often dictate the ease of application.
Of the three epoxy formulations, the 100-percent solids formula is the best. These epoxies form a thick, impact-resistant, and robust coating on surfaces.
Epoxies also boast a self-leveling property, making them perfect for surfaces with imperfections such as cracks and holes.
Epoxies are preferred floor coating on warehouses and garages due to their unparalleled robustness and impact resistance.
However, the coating tends to be vulnerable to the sun’s UV rays and will turn yellow when exposed to sunlight. This happens despite epoxy having UV inhibitors in its formula.
Epoxy pros and cons
Here are features that make epoxy a suitable flooring solution. Also included are the areas where it falls short.
Pros of epoxy
- It is incredibly strong and impact resistant
- Epoxy forms a thick, self-leveling coat ideal for filling cracks and other surface blemishes.
- It is highly resistant to water and moisture
- It offers superior adhesion to different surfaces.
Cons of epoxy
- It is time-consuming to apply
- It is prone to yellowing due to sunlight exposure.
What is the difference between polyurethane and epoxy?
The main difference between epoxy and polyurethane is their hardness. While both materials are thermosetting resins, epoxy dries to form a harder, higher-strength coating, while polyurethane is flexible and more durable.
So, epoxy coatings provide greater impact resistance, while polyurethane surfaces are more scratch-resistant and resistant to cracking due to extreme temperature changes.
Below is a detailed comparison of polyurethane and epoxy coatings.
Polyurethane vs epoxy side-by-side comparison
Both polyurethane and epoxy are thermosetting polymer resins, so they dry to form coatings that do not soften when heated. However, the two materials are not the same. They have significant dissimilarities that can make one a better solution for your needs than the other.
1. Polyurethane vs epoxy: Strength and flexibility
Epoxy is a higher-strength flooring material than polyurethane, which is more flexible. The greater physical strength of epoxy coatings makes them more resistant to physical impact, which is advantageous on hardwood floors.
In comparison, polyurethane’s flexibility allows it to resist scratching and extreme temperature changes better.
As a result, polyurethane will retain its pristine condition for longer than epoxy. So, while epoxy coatings will resist heavy objects and physical forces better, polyurethane does a better job of withstanding impacts and scratches.
Verdict: Epoxy’s hardness makes it susceptible to cracks.
2. Epoxy vs. polyurethane: Durability
While polyurethane is a softer material than epoxy, it typically lasts much longer than epoxy. A coat of polyurethane can last as long as 20 or more years without requiring a makeover.
However, polyurethane holds up a lot longer before it needs to be replaced, often lasting over 10 years compared to epoxy’s 2 years.
3. Cost of installing polyurethane vs. epoxy
Epoxy and polyurethane have different upfront and long-term costs. Epoxy typically costs approximately $3 to $6 per square foot, while polyurethane is around $5 to $7 per square foot.
This means you will pay more for polyurethane than epoxy. However, polyurethane can be more cost-effective than epoxy.
Your commercial epoxy floor coating will typically need replacing every 1.5 years. So you will spend more on epoxy in the long run
since polyurethane may take up to 30 years on your hardwood floor without needing replacement if you take good care of it.
Verdict: Poly is more expensive upfront but cheaper in the long run.
4. Chemical and temperature resistance
Polyurethane boasts superior resistance to chemicals and temperature. Thanks to its flexibility, the coating can tolerate drastic temperature changes from extreme cold to extreme hot without cracking.
Acids and other household chemicals spilling on your polyurethane-coated floor will wreak no havoc.
This chemical-resistant property of polyurethane makes it ideal for sealing hardwood floors exposed to harsh cleaning products and foods.
Epoxy is equally resistant to chemicals but not as well as polyurethane. It can withstand cleaners, making it a suitable coating for commercial kitchen flooring.
However, epoxy is limited in its chemical resistance. Exposure to certain chemical spills can cause significant discoloration.
Verdict: Polyurethane has better chemical resistance than epoxy.
5. Temperature Resistance
Epoxy can withstand high temperatures well, but it becomes vulnerable if the temperature extremes fluctuate often.
It is a popular flooring solution for commercial setups such as warehouses and commercial kitchens. Commercial kitchens are characterized by hot liquids and cooking equipment heating the floor.
The hardness of epoxy means it can easily crack when subjected to extreme temperature fluctuations causing drastic expansion and contraction.
In contrast, polyurethane has excellent temperature resistance and will take on such extreme temperature fluctuations without a problem. Poly’s flexibility means it can easily expand and contract, keeping it from cracking.
Verdict: Polyurethane has a better thermal resistance
6. Moisture resistance
Epoxy has better moisture resistance, making it a better flooring solution in areas that experience water and moisture problems.
Its moisture resistance also contributes to easier installation. You will unlikely encounter cosmetic issues associated with moisture when working with epoxy. It will adhere properly to the wood and start curing problems.
Even if you apply epoxy in humid weather, it will dry normally and come out hard when cured.
In contrast, polyurethane has low moisture resistance. If you apply poly on a humid day, you may easily end up with unsightly bumps in the coating.
Humidity and high substrate moisture content will also hinder polyurethane’s drying process. Therefore, you can expect it to take longer to dry in humid conditions.
Verdict: Epoxy is more water resistant and ideal for damp or mist conditions
7. Poly vs. Epoxy: Installation time
Epoxy flooring takes much longer to install, which can be a significant drawback when you have a tight timeline.
When installing it on your business premises, you may have to remain closed for business for several days. This is because epoxy has a longer dry time, taking as many as 7 days to dry and achieve the desired hardness.
In contrast, polyurethane installation can happen over a weekend, followed by 24 to 48 hours of drying time.
The project can be completed even sooner for water-based poly, thanks to the formula’s short drying time. This quality makes polyurethane a better flooring solution for users on a time crunch.
Read our detailed comparison of water-based and oil-based poly.
Verdict: Polyurethane has a shorter installation time
8. Thickness and consistency
Polyurethane exists as a viscous liquid. However, its consistency is nowhere close to that of epoxy. The latter is a thick material that easily fills in cracks and holes on the substrate. This makes epoxy a perfect solution for uneven surfaces.
Epoxy does not just coat the substrate surface; it fills the cracks and dents. And the thickness also means the coat is self-leveling, which can make it easier to work with.
Verdict: Epoxy is thicker and better for uneven surfaces
9. Epoxy vs. polyurethane: sheen and texture
Polyurethane comes in many sheen levels to choose from. You can go for high-gloss, semi-gloss, satin, or matte finish. This variety allows you to choose your preferred sheen.
Epoxy has limited options in sheen levels. It has a hand-troweled texture, which is all you get when you choose it for your hardwood floor.
The epoxy surface texture can get chalky over time, effectively hurting its aesthetics.
Verdict: Polyurethane offers more options for sheen and texture
10. UV Resistance
Polyurethane has greater resistance to the effects of the sun’s damaging rays. It will do a better job of retaining its color in the long run, even when exposed to sunlight.
Epoxy tends to be vulnerable to the sun’s UV rays despite having UV inhibitors in most formulations.
Exposure to sunlight usually causes discoloration and fading on epoxy-coated surfaces.
Verdict: Polyurethane has better UV resistance
Which is stronger, polyurethane or epoxy?
Epoxies are much stronger than polyurethane, which is flexible and more scratch resistant. In comparison, epoxy forms an incredibly hard coat on the substrate once dry. This makes it an excellent flooring solution where impact resistance is required.
Is polyurethane or epoxy better for wood?
Polyurethane offers the best durability for wooden surfaces. While epoxy is much stronger than polyurethane, it can become brittle over time, hurting its durability. In comparison, polyurethane is flexible, so it remains sound for decades. It also offers various sheen levels to choose from.
What coating is stronger than epoxy?
Polyurea, a 2-step resin, is four times stronger than epoxy. The material is also 98 percent more flexible, making it extremely durable and far superior to epoxy resin.
Polyurethane vs epoxy, which one should you choose?
Both epoxy and polyurethane are excellent flooring solutions that can benefit your hardwood floors. However, their unique characteristics make each product suitable under different circumstances.
Use epoxy coating for your hardwood floor if you want maximum strength and impact resistance, such as on a garage floor.
However, go for polyurethane if you want a long-lasting solution that will not force you to refinish the floor every few years. Polyurethane will also offer better resistance to scratching, extreme temperature changes, and chemicals.
Or, combine polyurethane and epoxy by layering poly over an epoxy base coat to get the best of both worlds.