Epoxy vs Polyurethane

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Epoxy and polyurethane are high-performance resins used for coating concrete and metal. Polyurethane and epoxy are resins that form a durable, waterproof coating. Although they both create a glossy look, they are not the same.

In this article, we compare epoxy vs polyurethane, the different types, and uses.

Epoxy Coatings and Finishes

Epoxy is surface tolerant, which means it protects metal from corrosion. It tends to fade and turn chalky over time.

There are many types of epoxy floor coatings. Which one you should use will depend on your surface.

Epoxy floor coated court

100% Solids Epoxy

100 solids are a category of epoxies for use as primers, middle coats, and topcoats. You can also use solid epoxies to resurface concrete.

Solid epoxies contain slight to no VOC (Volatile Organic Compounds). These are chemicals that emit gas, causing health problems. So solid epoxies are excellent and safe for indoor use.

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High Solids Epoxies

High solid epoxies protect concrete and steel from corrosive chemicals like alkalis and acids.

A high solid epoxy consists of epoxy resin and a curing agent. Many have the ability to cure fast and in low temperatures.

Polyamide Epoxies

Polyamide epoxy is a more economic solution that works as a primer and a finisher. But it doesn’t protect against harsh chemicals.

Use polyamide epoxies in areas like basements or game rooms. A garage wouldn’t hold up with a polyamide epoxy floor.

Cycloaliphatic & Novolac Epoxies

Cycloaliphatic and Novolace have high chemical resistance. These are ideal for containment tanks, trenches, and internal tank linings.

Novolac epoxies can survive 37% HCL for spillage and splash and 98% sulfuric acid. Most industrial and home settings won’t need these epoxy types.

Water-Based Epoxies

Water-based solvents are thinner than other epoxies, making them ideal for a DIY job. Once mixed, you can roll it onto the floor to apply.

Water-based epoxies have no odor. So they’re great for breaker rooms, locker rooms, home garages, and areas with light traffic and low chemical exposure.

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Man holding a can of polyurethane

Phenalkamine

Phenalkamine epoxies cure quickly. They are ideal for applying in low temperatures and cold weather.

Phenalkamine offers decent protection from chemicals. It has an easy application process that adheres to many surfaces. And it has low viscosity, so it’s odorless and safe.

Polyester Epoxies

Polyester epoxies are great to use as anti-graffiti coatings. When polyester epoxies cure, it creates a high gloss finish that resembles tile.

The biggest benefit is you can scrub it without damaging the surface. Polyester epoxy is also resistant to chemicals, making it a versatile epoxy.

Polyurethane Finish and Coating

Polyurethane (PU) is another material used to seal concrete and metal. This product provides a glossy appearance, better color stability, and stronger UV protection.

But, polyurethane is sensitive to moisture and humidity, which restricts your application window. Apply polyurethane in low humidity, usually from 10 AM to 4 PM. 

Some PU flooring offers more chemical, impact, and abrasion resistance than epoxies.

Moisture Cured Urethanes

Moisture cured urethanes create a hard, durable finish that changes color over time.

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This urethane adhesive can bond to many surfaces, including metals and plastics. But it will not work on concrete.

The best thing about moisture cured urethanes is that they rely on humidity and moisture to cure. So you’re not limited on when you can apply this one component urethane.

Epoxy floor coated court

Acrylic Polyurethanes

Acrylic polyurethane consists of aliphatic compounds that create a flexible surface that’s impact and scratch-resistant.

It’s also UV resistant, so the product doesn’t turn yellow over time, which is a common problem with using epoxies.

Aliphatic polyurethanes are usually 55% to 75% solid. It dries into a one to four-millimeter layer that provides a glossy protective finish.

Acrylic polyurethane holds color well. It’s an excellent finish to use for protecting metallic exterior surfaces.

Polyester Polyurethanes

The most durable type of finish to use for concrete and metal is polyester polyurethane. This finish offers the most impact and scratch-resistant while retaining its glossy color.

This material is 100% polyester resin, rated a true Chemical Resistant Urethane (CRU). And it is resistant to abrasive chemicals such as grease, oil, salt, Skydrol, acids, and high traffic.

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Polyester polyurethane is for service bay floors, plane hangars, and high traffic areas.

Epoxy vs Polyurethane

Epoxy creates a hard protective coating that bonds to concrete or steel.

Polyurethane is another resin for floor coating concrete and steel. This chemical protects against damage, UV rays, and water.

Epoxy Benefits

Epoxy is an excellent adhesive to use for concrete surfaces. They offer chemical resistance and waterproofing. And they can last up to twenty years when applied and treated.

Many epoxies go on clear, giving a glossy appearance that’s easy to clean. Epoxies can be water or solvent-based: the more solvents, the stronger the smell. Water-based epoxies have low to no odor.

Epoxy is a thin resin that can fill cracks in concrete. It lays a coat of 8 to 15 millimeters that can self-level by bonding with the concrete. 

Person applying polyurethane on the floor

Polyurethane Benefits

Polyurethane resins come in different finishes, including satin, semi-gloss, and high gloss. These resins have a higher resistance to chemicals.

And they offer UV-protection, making them useful for outdoor buildings. Polyurethane is often used as a top coat over epoxy to prevent yellowing.

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The biggest benefit is it is more durable. Floors coated with polyurethane can last close to four times longer than epoxy.

Which Coating is Better?

Which coating you choose depends on your needs. Floors that see a lot of use and chemical or sunlight exposure, do better with a polyurethane resin.

For a low odor, glossy coating that offers some resistance to use and chemicals, you could get by with an epoxy coat.

What Should I Use on My Floor?

Both epoxy and polyurethane work well to seal concrete floors. If your floor gets a lot of sunlight, you’d want to use polyurethane, so it doesn’t yellow. Epoxy works well for most home uses.

Additional Questions

Can You Use Polyurethane Like Epoxy?

Polyurethane and epoxy provide a protective seal to your surface. But polyurethane doesn’t repair and seal cracks in concrete. You apply epoxy using a roller while polyurethane is applied by brush.

Which Is Harder Epoxy or Urethane?

Urethane gets harder than epoxy. But they both cure to a hard, durable surface that resists impacts. Urethane does have more flexibility to it, which causes strength.

Can You Use Polyurethane On Resin?

Polyurethane applied over epoxy resin can add strength and protect the epoxy from sunlight and color change.

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.