Polyurethane is a very common varnish that offers a protective coating to your wooden surfaces. There are two main types: oil-based and water-based. Nick O’Keefe, the owner of Oak City Coatings, LLC, explains that water-based polyurethane goes on clear, while oil-based polyurethane has an amber tint to it. Read on to find out if you can put polyurethane over paint.

Can You Put Polyurethane Over Paint?

Jay Sanders of Castle Dream Construction says polyurethane can be applied over paint. So, if you’re looking into polyurethane as an option to protect your painted surfaces, you’re good to go. But be sure to apply it carefully and correctly! “Always apply over fully dry and cured paint to avoid smudging, ” cautions Rachael Daley Otto, paint department head at Fleury Lumber.

What prep should I do before putting polyurethane over paint?

In order to keep your surfaces looking beautiful, you’ll need to apply the polyurethane correctly. Sanders has a few tips for prep work before you begin applying the polyurethane:

  • The primary step is to prepare the project site by cleaning the surface. It is important to ensure that the surface is free of dust.
  • You can use fine-grit sandpaper to lightly sand the painted surface to promote adhesion.
  • After sanding, wipe away the surface with a damp cloth as a last step.

Otto also has several suggestions:

  • Make sure the paint is dry and cured.
  • Test a small area first.
  • Make sure you are using the appropriate polyurethane (exterior or interior).
  • Have the materials handy that you will need for clean up.
  • Always work in a well-ventilated area and wear a mask.

What Type of Polyurethane Should I Use Over Paint?

Both types of polyurethane can be used over paint; the main differences between them are durability and color. “Higher gloss paints should be slightly scuffed, but with a matte, flat, chalked or craft paint, you can apply the polyurethane following the directions on the can,” Otto says. However, Otto adds that “oil-based polyurethane will yellow over time while water-based will not.”

Oil-based polyurethane

“[Oil-based polyurethane] is best suited for surfaces requiring extra durability, such as high-traffic areas. However, it is not recommended for light-colored paints, as it can become yellow, over time,” Sanders explains. It’s a great candidate for flooring, however, where that extra protection is necessary.

Water-based polyurethane

According to Sanders, water-based polyurethane is recommended for light-colored paints since “it mostly dries clear and is suitable for preserving the original paint color.” These paints include:

  • Chalk paint: “To avoid yellowing, it is recommended to use water-based polyurethane. Chalk paint has a porous surface, [which] can absorb oil-based polyurethane,” Sanders cautions. This absorption can have a negative impact on the overall finish of the surface.
  • Latex paint: According to Sanders, “you can use both oil-based and water-based polyurethanes for latex paint. However, to attain a clear finish- it is better to choose water-based polyurethanes. Oil-based polyurethane may slightly turn latex paint yellow.” So if your concern is maximum durability and you can live with the yellowing, feel free to use oil-based. But if you want to preserve your colors, stick to water-based.
  • Acrylic paint: “Water-based polyurethane is recommended for maintaining the clarity and vibrancy of the paint. Oil-based polyurethane can cause discoloration in acrylic paint,” Sanders explains.

So there you have it; you can use polyurethane over paint. However, in most instances, you should opt for a water-based option due to oil-based polyurethane’s tendency to cast a yellow tint.

Next, find out if polyurethane is waterproof.

About the Experts

Author
Rebecca Wright Brown
Rebecca has been her dad’s DIY assistant since she was old enough to walk. Prior to Family Handyman, she worked as a freelance writer and editor across industries.   
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