How to Paint Over Polyurethane Woodwork

You can paint over a surface of polyurethane varnish if you prepare it properly. Polyurethane is typically hard, durable and glossy, and it is these qualities that make a finish vulnerable to chips and flaking. You don't have to remove all the varnish before you start painting. Preparation will pay off in the long run by providing a long-lasting finish.

Things You'll Need

  • Clean, lint-free cloths

  • Mineral spirits

  • Wood filler

  • Protective face mask

  • Fine-grade sandpaper

  • Liquid sandpaper (optional)

  • Paintbrushes

  • Oil-based primer

  • Oil-based topcoat

Step 1

Clean the surface with a cloth dampened with mineral spirits. Fill chips, holes or other damage with wood filler.

Step 2

Sand the surface with fine-grade sandpaper. Wear a protective face mask; dust from polyurethane varnish is toxic. Roughen the surface enough so the paint will adhere to it. Remove dust with a clean cloth and mineral spirits. Alternatively, use a liquid sandpaper that will dissolve the gloss surface of the varnish. Follow the manufacturer's directions.

Step 3

Apply a coat of primer to the wood. Don't skip this step; primer provides the proper surface to which a topcoat will adhere; it also disguises areas of filler. Allow to dry overnight.

Step 4

Paint on the first application of a topcoat. Let it dry overnight, then lightly sand and wipe the surface with a clean cloth and mineral spirits.

Step 5

Apply the second coat of topcoat. Allow the surface to cure for 72 hours before handling it or placing objects upon it.

Tip

Avoid “one-coat” paints; they are expensive and do not provide a long-lasting finish. If you do inadvertently sand back to the wood, you need to make sure that your primer is capable of stain-blocking, as natural wood can bleed resins that will force their way to the surface and spoil the painted finish.

Warning

Make sure your work area is well-ventilated. Dispose of used cloths carefully, as they are flammable. Do not use latex or water-based paint over polyurethane; the finish may crackle and it would be difficult to remove the paint.

References & Resources