Polyurethane is a common finish used on wood surfaces like floors, furniture, cabinets, and more. Its durability and protective qualities make it a popular choice. But what if you want to change the color of your polyurethane finished surface? Can you paint over polyurethane?
The short answer is yes, you can paint over polyurethane. However, some important steps must be taken to ensure proper adhesion and a long-lasting finish. In this complete guide, we’ll cover everything you need to know about painting over polyurethane.
Overview of Painting Over Polyurethane
Painting over polyurethane is doable but requires proper preparation and technique for success. The keys are:
- Properly preparing the surface through cleaning and sanding
- Applying a bonding primer or adhesion promoter
- Using the right type of paint – oil-based and latex paints work well
- Applying thin coats of paint and allowing proper drying time between coats
The paint may not adhere correctly without proper prep work and could end up peeling or chipping off. You can successfully paint over polyurethane with the right steps and get great results.
Reasons to Paint Over Polyurethane
There are several reasons you may want to paint over an existing polyurethane finish:
- To change the color – Painting is an easy way to give new life to a polyurethane finished surface without having to strip and refinish the wood underneath fully.
- To update the look – Applying a trendy paint color over dated oak cabinets with a poly finish is a budget-friendly way to make the space feel fresh and new.
- To cover discoloration or damage – Paint can mask imperfections like water marks, scratches, and sun fading on old polyurethane finishes.
- To create a distressed or worn look – A coat of paint over polyurethane can help achieve a timeworn, weathered aesthetic as part of a restoration project.
- To unify mismatched elements – Painting over different wood pieces finished in polyurethane is an easy way to make them coordinate.
Prep Work: Cleaning and Sanding
Proper surface preparation is crucial for success when painting over polyurethane. The polyurethane coating creates a smooth, non-porous surface that paint can have trouble adhering to. That’s why scuffing up and “tooth” the surface through cleaning and sanding before painting is important.
First, thoroughly clean the surface with a degreasing cleaner to remove dirt, grease, wax or other residues. TSP substitute is a good degreasing cleaner option for this task. Scrub the surface, let the cleaner sit for 5-10 minutes, then rinse it off and let dry fully.
Next, sand the polyurethane lightly to rough up the smooth surface. This helps the paint cling to the finish rather than sliding off it. Use 150-220 grit sandpaper for light sanding. The goal is not to sand down to bare wood, but just to scuff up the glossy polyurethane coating.
Focus sanding on areas that will show wear first – edges, corners, and any decorative carvings or moldings. Use a sanding sponge for hard to reach spots. Wipe away all sanding dust with a tack cloth once complete.
Some options beyond sanding to prep the surface include:
- Deglosser – Wipes on like a liquid sandpaper to etch smooth surfaces
- TSP Substitute – Acts as a deglosser when left to sit on surface for 10-15 minutes before rinsing
- Liquid sandpaper – A mild abrasive solution that roughs up finishes
Priming Over Polyurethane
Priming is an essential step when painting over polyurethane or any non-porous surface. Primers are formulated to adhere tightly to slick surfaces and provide a textured base that paint can grab onto.
Use a high-quality bonding primer when painting over polyurethane. Some top options include:
- Zinsser B-I-N Primer – A shellac-based primer that sticks to the slickest surfaces and seals in stains and odors.
- Kilz Adhesion Primer – Water-based acrylic-latex primer that bonds tightly and blocks stains.
- Zinsser Bulls Eye 1-2-3 Primer – Strong-bonding water-based acrylic primer suitable for multiple surfaces.
Read the manufacturer’s recommendations, but most bonding primers can be used under oil and latex paints. Apply two thin, even coats of primer using a good quality roller cover or paintbrush and allow each coat to fully dry before adding the next. Lightly sanding between coats helps improve adhesion.
Priming over polyurethane allows for proper paint adhesion and provides extra protection from bleed-through of any stains in the wood below the polyurethane finish.
Choosing the Right Paint
Oil-based and latex paints will work well over polyurethane, though oil-based paint may be preferable for enhanced durability. Here are some tips for choosing paint when painting over poly:
- Oil-based paint – More durable and longer-lasting than latex paint; ideal for cabinets, furniture, trim and other high-use surfaces. Paints like enamel and alkyd paints work well.
- Latex paint – More affordable, lower-odor option. Look for a high-quality latex formulated for furniture and cabinets, or a bonding latex. Latex requires more coats for full coverage.
- Chalk paint – Can be applied directly over polyurethane without separate priming step. Provides a matte, distressed finish. Best for furniture projects.
- Darker colors – Help conceal imperfections and require less coats for coverage. Whites and pastels show more flaws.
- Satin or semi-gloss – Offer more durable finishes than flat sheens. Better at hiding imperfections too.
Buy a quality brand of paint and choose products specified for your project – whether it’s furniture paint, cabinet paint, floor paint, etc. Check that the paint is compatible over polyurethane or other existing finishes.
Application Process for Painting Over Polyurethane
Follow these tips when applying paint over a polyurethane finished surface:
- Allow primer and paint to acclimate to room temperature before using.
- Use a quality nylon/polyester brush or a short nap microfiber paint roller. Avoid foam rollers.
- Apply paint in thin, even coats. Thick coats can bubble or crack.
- Work methodically section by section to maintain a wet edge and prevent lap marks.
- Let each coat fully dry before adding the next – this may take 24 hours or more.
- Sand lightly between coats with 220 grit sandpaper to improve adhesion.
- Opt for 2-3 thin coats of paint for full coverage over dark finishes.
- Clean brushes and rollers promptly after use following paint manufacturer instructions.
Applying thin coats is paramount, allowing ample drying time between coats. Rushing the painting process leads to chipping, peeling and poor adhesion over polyurethane. Patience leads to better results.
Tips for Painting Over Different Polyurethane Finishes
The techniques for painting over polyurethane are largely the same regardless of the type of finish. However, there are some additional factors to keep in mind based on the sheen level of the polyurethane:
Gloss Polyurethane
- Very slick, non-porous surface that paint has difficulty adhering to
- Requires thorough deglossing and sanding for paint prep
- Satin or semi-gloss paint finishes recommended over gloss poly
- Darker paint colors help hide imperfections better
Satin Polyurethane
- Provides good surface tooth for painting without extensive sanding
- Satin, semi-gloss or high-gloss paint will work over satin poly
- Lighter paint colors possible since surface imperfections less visible
Matte Polyurethane
- Easy surface for paint adhesion without much prep work
- Higher sheen paint finishes like satin are recommended
- Can use lighter paint colors without concern of flaws showing
Regardless of the starting polyurethane finish, proper prep work and using the right paint products lead to success.
Special Considerations for Different Surfaces
Painting over polyurethane on different surfaces like wood, metal, and plastic all follow the same basic process, but there are some unique factors to consider for each:
Wood Surfaces
- Softwoods like pine more prone to absorb paint than hardwoods
- Unstained wood may require stain-blocking primer for tannin bleed prevention
- Filling nail holes, cracks, and imperfections important before painting
Metal Surfaces
- Clean oil, grease, rust and other residues from metal before priming
- Use a rust-inhibiting primer on iron, steel and other metals prone to rust
Plastic Surfaces
- Use primer specifically designed for plastics and synthetics
- May require light sanding to create surface tooth for painting
- Heat gun can smooth ripples or impressions on plastic before painting
Mistakes to Avoid When Painting Over Polyurethane
Painting over polyurethane correctly takes careful preparation and application. Here are some common mistakes to avoid:
- Skipping the prep work – Without thorough cleaning, sanding, and priming, paint won’t properly adhere. Rushing this step leads to peeling or chipped paint down the road.
- Using the wrong paint – Make sure to use a high-quality paint designed for the surface you’re painting, whether it’s furniture, flooring, metal, etc.
- Applying paint too thick – Thick coats of paint are prone to cracking and creating a bumpy finish over polyurethane. Opt for several thin coats instead.
- Not allowing proper dry time – Rushing the painting process leads to tacky paint that won’t cure correctly or adhere well. Give each coat ample drying time.
- Scuffing between coats – It’s crucial to sand between paint coats over polyurethane lightly. This helps each layer bond tightly together.
- Choosing flat paint – Higher sheen paints like satin, semi-gloss and gloss provide a more durable finish over polyurethane.
Avoiding these common missteps will set your paint job up for success rather than failure. Proper prep work, patience, and using the right painting products leads to great results.
How Long Does Paint Last Over Polyurethane?
How long paint lasts over polyurethane depends on several factors:
- Surface Use – High traffic areas like floors and cabinets wear faster than surfaces like furniture and walls.
- Paint Quality – Higher quality paints formulated for durability hold up better over time.
- Prep Work – Proper sanding, cleaning and priming helps paint adhere tightly and last longer.
- Coats Applied – Additional coats of paint build added protection and longevity.
With the right prep work and application process, painted surfaces can last 3-5 years over polyurethane. Areas of wear may need touch ups more frequently. Using higher quality paints and primers improves longevity, as does applying 3-4 thin topcoats.
Removing Paint from Polyurethane
If you need to remove paint from a polyurethane surface, here are some options:
- Paint remover – Chemical strippers work well to soften and lift paint from polyurethane. Use safety precautions.
- Heat gun – A heat gun can soften paint and scrape it off while keeping the polyurethane intact.
- Sanding – Use a drum sander, belt sander, orbital sander to remove paint to the polyurethane.
- Refinishing – In some cases, it may be necessary to fully refinish by stripping the polyurethane and paint entirely.
Test paint removers or heat on a small area first. Removing paint may also take off some of the polyurethane finish. Be cautious when using power sanders to avoid removing too much.
Painting Over Polyurethane FAQs
Here are answers to some frequently asked questions about painting over polyurethane:
Can you paint over polyurethane without sanding?
It’s not recommended. Sanding provides necessary texture for the paint to bond properly. Without it, paint may eventually peel. Lightly scuff sand before painting over poly.
Does paint stick better to oil or water-based polyurethane?
Oil-based polyurethanes require more sanding but provide a slick surface to which paint can adhere when properly prepped. Water-based polys are more porous for better grip without sanding but may require sealing.
How long should primer dry before painting over polyurethane?
Always follow the manufacturer’s recommended dry times, but typically primers dry within 1-2 hours. For best adhesion, let primer dry overnight before painting over polyurethane.
Can you use chalk paint over polyurethane?
Yes, chalk paint can adhere to polyurethane without separate priming. Light sanding is still advised for longest wear. Finish with a topcoat of polyurethane for protection.
Should I degloss before painting over polyurethane?
Deglossing provides added assurance for proper paint adhesion. But light sanding alone is often sufficient. Try a small test spot with just sanding first. If paint doesn’t adhere well, use a deglosser.
Conclusion
Painting over polyurethane effectively changes the color and look of furniture, floors, cabinets and other surfaces finished with polyurethane. You can achieve great results with proper preparation through cleaning, sanding, and using the right primer and paint. Oil-based paints provide enhanced durability but quality latex paint also works well. Avoid common mistakes like skipping prep work or applying paint too thickly and you’ll get a long-lasting finish. Use these best practices for painting over polyurethane and transform the look of your space.
