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Differences Between Epoxy vs.Polyurethane Thin Film Topcoats

Epoxy and polyurethane thin film topcoats are two types of high performance floor coatings that can be used to strengthen, protect, and improve the aesthetics of an industrial flooring system. Both have significant advantages as well as some drawbacks, which is why we often recommend using a combination of both, when possible. However, the following comparison may help in assessing which material may best suit the specific needs in a particular facility.

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This gorgeous FloroChip floor, expertly installed by Baker Flooring of FL, shows how epoxy and urethane can be combined for optimal results.

Epoxy Systems and Thin Film Topcoats

Epoxy is a hugely popular, cost-effective concrete-treating solution for industrial, commercial and institutional settings, as well as for small business owners and even private individuals. When used as a topcoat over a concrete surface, a single coat of 100% solids, zero V.O.C. epoxy can typically be applied at 8 to 20 mils (1 mil = 1/1000”) thick, depending on the precise formulation. Some of epoxy’s popularity can be attributed to its many application options. With its exceptional bonding abilities, the right lower viscosity epoxy types can make excellent primers over properly prepared concrete, even when surfaces are old, worn or imperfect. Slight thicker viscosity product can makes it possible to fill in small cracks and divots, helping to smooth out a previously uneven surface in a way that thin film polyurethane cannot. Epoxy is also extremely hard and provides outstanding durability, providing lasting protection against scratches and abrasions.

One drawback of epoxy is that it may discolor over time. Even most high quality UV-resistant epoxies will begin to turn yellow or amber with exposure to sunlight.

Polyurethane Thin Film Topcoats

Compared to epoxy, today’s ultra-high solids, low V.O.C. polyurethane topcoats tend to require much thinner application, coming in at a nominal 2 to 3 mils dry film thickness. However, they are also much more flexible, allowing them to be exceptionally effective in absorbing impact. Polyurethane on average also has roughly three times the abrasion resistance properties of typical epoxy, and provides much stronger protection against harsh chemical solvents. In addition, urethanes — specifically the aliphatic types – are UV resistant and can maintain their color over time, even in areas with sun exposure.

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Because it is applied so thin, in contrast to some epoxy, polyurethane is not effective in filling in fine cracks or imperfections in the surface of the concrete. Urethanes also do not bond well when applied directly to slabs and typically require the use of epoxy or other primers as a first coat. Though the V.O.C. content in some of the newer industrial-grade urethane floor coatings can be nearly zero, many do still contain some solvent, necessitating contractors to consider air management during installation.

Why a Combination is Best

By using both epoxy and polyurethane together on the same concrete surface, it is possible to get the advantages of each product, while mitigating some of their respective drawbacks. An initial 8 mil application of low viscosity epoxy as a primer will best penetrate the opened pores of the mechanically prepared concrete surface. This can be followed by a heavier-bodied epoxy at 15 mils to help even out the surface of the concrete, provide a solid layer of protection, good depth of color, and an excellent base for the polyurethane. The application of 3 mils of aliphatic urethane enhances the epoxy’s abrasion and chemical resistant properties, and furnishes a colorfast finish. An optional second topcoat of polyurethane in clear or color provides the ultimate in high performance flooring protection.

Whatever your concrete floor concerns may be, we at Florock are here to help. To discuss your facility’s needs and to get a better idea of the various flooring options, give us a call today.