How to Paint Over Polyurethane Finish

Key Points:

• Clean and sand the polyurethane to remove gloss for better paint adhesion.
• Use a primer designed for glossy surfaces to ensure paint sticks well.
• Choose acrylic latex or oil-based paint, applying thin coats for a smooth finish.

Painting over a polyurethane finish might seem challenging, but it’s a simple process with the proper steps. Whether you’re freshening up old furniture or giving a new look to woodwork, this guide will walk you through the process. We’ll break down the process into easy-to-follow steps and ensure it’s beginner-friendly. Let’s dive into the details.

What is Polyurethane Finish?

Polyurethane is a durable, protective finish used on wood. It is often applied to furniture, flooring, and other wood surfaces to give them a shiny, tough layer. However, this protective layer also makes it tricky to paint over, as it prevents new paint from sticking well.

But don’t worry; painting over polyurethane is completely doable with proper preparation and techniques!

Why You Need to Prepare the Surface

Painting over polyurethane can be difficult because the surface is slick. If you try to apply paint directly on top of it, the paint may not adhere properly, and the end result can be patchy or prone to chipping.

Preparing the surface gives the paint a better chance to stick, resulting in a smooth, long-lasting finish.

What You’ll Need

Here’s a list of supplies you’ll need:

• Sandpaper (120 and 220 grit)
• Tack cloth or damp rag
• Painter’s tape (optional)
• Primer (Bonding primer for glossy surfaces)
• Paint (Acrylic latex or oil-based)
• Brushes or roller
• Drop cloth or newspapers
• Protective gear (Gloves, safety glasses)

Step 1: Clean the Surface

Before sanding, the surface must be cleaned. Dirt, grease, or dust can affect how well the paint sticks. Use a damp cloth with mild soap or a degreaser to clean the polyurethane surface. Let it dry completely before proceeding.

Quick Tip:

Stubborn spots or sticky areas need a stronger cleaner or degreaser for better results.

Step 2: Sand the Polyurethane

Sanding is the most important step in preparing a polyurethane-coated surface for paint. This will roughen the shiny surface, allowing the primer and paint to adhere correctly.

1. Start by using 120-grit sandpaper. Lightly sand the surface, just enough to remove the glossy finish. You don’t need to obliterate the polyurethane; dull it.
2. After sanding with 120-grit, switch to 220-grit sandpaper to smooth the surface.
3. Wipe away the dust with a tack cloth or a damp rag to ensure the surface is dust-free.

Quick Tip:

Be gentle when sanding wood veneers or thin layers of polyurethane, so you don’t sand through the protective finish or damage the wood underneath.

Step 3: Apply a Bonding Primer

Priming is a key step when painting over polyurethane. With primer, the paint may peel or stick properly.

1. Choose the right primer: Use a bonding primer made for glossy surfaces. Oil-based or shellac-based primers work well because they adhere firmly to slick surfaces.
2. Apply the primer: Use a brush or roller to apply an even coat of primer. Make sure the surface is fully covered, with no bare spots.
3. Let it dry: The primer needs to dry completely before painting. Most primers take around 24 hours to dry but check the label for specific drying times.

Quick Tip:

Bonding primer is especially important for high-use surfaces, like tabletops or cabinets, to ensure the paint doesn’t chip later.

Step 4: Sand the Primed Surface (Optional)

Once the primer has dried, you can lightly sand the surface again with fine 220-grit sandpaper to smooth out any rough areas or brush marks. This step is optional but can give you a flawless finish.

After sanding, wipe the surface with a tack cloth to remove dust before painting.

Step 5: Apply the Paint

Now that the surface is primed, it’s time to apply your paint. Here’s how to get a great finish:

1. Choose the right paint: Acrylic latex or oil-based paint is best for painting over polyurethane. Both are durable, but oil-based paints offer better durability for high-traffic areas.
2. Apply the paint: Use a brush or roller to apply the paint in thin, even coats. Applying thin layers helps avoid drips and ensures smooth coverage.
3. Let it dry: Allow the first coat to dry thoroughly before applying a second coat. Depending on the type of paint, this could take anywhere from a few hours to 24 hours.
4. Apply a second coat: Once the first coat is dry, apply a second coat of paint. Two coats are typically enough to give you a nice, even finish, but feel free to add a third coat if necessary.

Quick Tip:

A high-density foam roller can help avoid brush marks and give large surfaces like tabletops or cabinets a smoother finish.

Step 6: Optional—Seal the Paint

If the surface you’ve painted will see heavy use, like a dining table or a frequently used piece of furniture, consider sealing the paint to protect it from wear and tear.

1. To protect the paint, use a water-based polyurethane or clear acrylic sealer. Ensure the sealer is compatible with the type of paint you used (oil-based or water-based).
2. Apply a thin, even coat of sealer with a clean brush and allow it to dry fully.

Sealing is only sometimes necessary for decorative pieces but is recommended for high-use items to extend the life of your paint job.

Conclusion

Painting over polyurethane doesn’t have to be complicated if you follow these simple steps. Here’s a quick recap:

1. Clean the surface to remove dirt and grease.
2. Sand the polyurethane to remove the gloss.
3. Prime with a bonding primer made for slick surfaces.
4. Paint using thin, even coats of acrylic latex or oil-based paint.
5. Seal the paint for added protection (optional).

By preparing the surface properly and using the right materials, you can successfully paint over polyurethane and give new life to old furniture, cabinets, or any wood surface. Happy painting!