can you paint over polyurethane

Can You Put Polyurethane Over Paint?

In Tips by Jamie P.

It is time to put the paintbrush away, finally. After hours of stripping, sanding, gluing, and painting you are ready to seal things up. But you are wondering what the best option is for your painted surface- can you put polyurethane over paint?

Yes, you can apply both oil-based and water-based polyurethanes over paint – for the best possible results add 2 to 3 drops of the same color paint into the polyurethane, this prevents a cloudy-looking poly finish. For the best possible adhesion make sure the surface is clean from any dust or debris.

You should keep in mind that oil-based polyurethane is likely to turn yellow when applied over light-colored paints, while water-based polyurethane will typically remain clear.

I have painted many furniture projects using a variety of paint types and different paint brands, and my go-to finish is polyurethane. I prefer to use water-based polyurethane over my painted projects for a number of reasons, which I will jump into below.

How Long Should Paint Dry Before Applying Polyurethane?

Often it is recommended to follow the label on the paint manufacturer’s product for when it is acceptable to apply a clear coat. Sometimes paint labels do not say anything about applying clear coats because not all paints are designed to have a clear coat applied over them, this doesn’t mean you can’t though. If this happens I typically follow the re-coat time on the paint label, which varies from paint to paint.

It is best to let paint dry a minimum of 4 hours before applying polyurethane with a sprayer. If you are brushing or wiping the polyurethane onto the surface you should wait 24 hours or until the next day, the longer it drys the less likely you are of causing damage to the paint during the polyurethane application.

The reason spraying time is much less is that if you are spraying you are not touching the surface. If you don’t touch the surface you can’t mess up the paint finish as easily. I have painted numerous projects in the morning and applied polyurethane on the same piece during the same day using a sprayer with no issues, I used water-based poly on painted furniture. I believe that when the painted surface is completely dry to touch, the piece can be sprayed with polyurethane.

Keep in mind that humidity and temperatures play a huge role in the paint drying process. In some places, your paint can dry as you are painting it, while others you go to bed and it’s still not dry in the morning, that’s the worst feeling… There is no real “perfect” time to add the polyurethane over your painted surface, but my rule of thumb is to make sure it is completely dry throughout.

The reason I wait longer to brush, wipe, or use a finish applicator to apply polyurethane is because of how the paint reacts in shorter times. Just because the paint is dry to touch does not mean it is as durable as it will be, paint takes time to cure, so the longer you wait the more scratch-resistant it becomes. Plus, if you happen to apply polyurethane by directly applying it (brush, wipe, etc), you risk areas being wet and smudging or rubbing these parts and ruining the paint surface. Then it is back to the start, not fun let me tell you.

You may hear people say “you can’t apply poly until the paint cures”, which is bizarre really. Paint can take weeks to fully cure, that’s not happening in my books. You can apply polyurethane over paint that is not cured, the paint will still cure with the poly over it. The polyurethane is going to take time to cure and harden too, and it is important if you sell items before the cure time to let them know to be careful for the next couple of weeks. Poly can take up to 30 days to fully cure and harden.

Does the Painted Material You Are Applying Polyurethane Over Matter?

I like to say this is a tricky question because there are so many variables, the project one person is doing compared to the next can differ in a million ways. In my head, I think of polyurethane as a great finish for wooden projects, when it comes to metal or concrete I would probably switch things up and start doing some research. I stick to using polyurethane on painted and stained wood surfaces, not much else truthfully.

If I did have a laminate piece of furniture, I would follow the same steps as if it were wood – besides that I would be using a different priming product. As a finish, I would spray water-based polyurethane over the laminate painted surface.

If it is a metal material I would probably use a clear enamel spray paint or lacquer, it would perform better than polyurethane any day. I paint metal all the time, the hardware on furniture is often zinc, copper, or brass and I apply spray paint on them a lot. Prep work is critical for painting metal, clean, sand, and paint. Once I painted my hardware I will apply a clear coat. You can use polyurethane as a protector in this situation, but handles and knobs are used all the time and I want durability. I will use lacquer or a clear enamel spray for ultra-durability, sometimes I even use gilding wax too. You can read my full guide on how to paint and refinish hardware here, there is a video showing the process.

Concrete is a different story altogether. I am not a concrete expert and I will tell you that with no hesitation. However, I did plan out to finish my garage floors but ended up moving out of my house, so that did not happen. But what I did learn is that polyurethane is not a super popular option for concrete surfaces, but it can be used. Other popular concrete options were epoxy, acrylic, and siloxane sealers.

Does my Paint Even Need Polyurethane?

You may be asking the wrong question because not all paints need a clear coat finish. Of course, the type of project you re doing is a major factor, but the type of paint you choose can eliminate the need for polyurethane. Some paints now for furniture actually say they are a paint and protector all-in-one, which is great, but I will still throw 2 coats of poly on for extra protection.

However, various enamel paints and oil-based paints are extremely durable. These paints are known to be even more durable than polyurethane, so using polyurethane may not be required as the paint can handle regular traffic and use.

Can You Put Polyurethane Over High Gloss Paint?

Yes, you can apply polyurethane to high gloss paints, but be aware that polyurethane does not adhere as well to glossy surfaces in comparison to other finishes like flat, matte, or satin. Keep in mind that semi-gloss and gloss finishes are more durable than flat, matte, satin, and chalky finishes. This can also be considered when in the process of choosing paints and finishes.

Why I Use Water-Based Polyurethane Over Paint (Instead of Using Oil-Based)

You may wonder why I would choose water-based poly over oil-based poly for my furniture projects. It is said that oil-based polyurethane is more durable than water-based, but today water-based polys can be extremely durable. You can actually buy water-based flooring polyurethane, so if you can use it on hardwood floors it must be pretty durable.

I have found that certain products are stronger than others, my favorite water-based poly now is Varathane Diamond Wood Finish. It usually dries to touch pretty quickly, 60 minutes in the right temperatures, and when spraying I can re-apply coats in a few hours over painted surfaces. This stuff provides a durable piece of painted furniture and I am happy with the results!

I also choose water-based poly over an oil-based poly because I can use water to clean it up and I can use water to thin it for spraying. This makes life so much easier, trust me. When spraying polyurethane I will thin it with about 10% water, this produces a nice smooth finish. Oil-based products need to be thinned with a paint thinner, which costs more than water from the tap.

Now clean-up. Water cleans up water-based poly in a hurry, I take my sprayer to the sink and get to it. If using oil-based polyurethane, the cleaning process is much more difficult. You need to use mineral spirits and really rinse and repeat in a safe area. Plus, these chemicals are not allowed to be tossed down the sink, location laws differ, but then you need to safely dispose of the chemicals. That’s no fun, it takes time and more time.

Don’t get me started on the fumes… Oil-based products do have a stronger odor than water-based, but the difference is in safety too. Breathing in oil-based poly fumes is much more dangerous than water-based, and the same with cleaning products. Water is safe, mineral spirits and thinners are very toxic in comparison, plus they are super strong in odor too.

So, there you have it, the main reasons I go with water-based polyurethane vs oil-based polyurethane when applying over paints. If you want to learn how I apply polyurethane (bubble-free) check out my detailed guide here.

How to Apply Polyurethane Over Paint (Step-by-Step)

Applying polyurethane over paint is a bit different than applying it over wood, you need to be more careful with painted surfaces. You will see streaks much easier in polyurethane when applied over paint, when applying over wood the poly almost absorbs into the surface streak-free, plus it blends in a lot better.

I will explain how to apply polyurethane over painted surfaces using a foam applicator and my favorite method using a sprayer.

1. Make Sure the Paint is Dry Before Anything

Remember, if the paint is wet you will wipe wet paint ruining the painted finish. This will cause you to need to sand when everything is dry and then repaint. Visually paint can trick your eyes, it can be hard to tell if it is wet or dry. Waiting longer is never a bad idea and when you plan to touch it to check, test it in an inconspicuous area first.

2. Make Sure the Painted Surface is Clean

Now anything you see on the paint will be visible through the polyurethane, if there is dirt you need to wait until the piece has been drying for some more time. I often grab a tack cloth and use it to wipe the surface clean from any dust or debris that happened to mix into the paint.

I will NOT use any cleaning products that will get the paint wet, just keep things dry with a tack cloth. Cleaning products at this stage may ruin the polyurethane’s adhesion.

3. Super Light Sanding (Optional)

I rarely will sand at this point because I do not want to risk scratching the paint, however, you can do a light scuff with a 300 or higher grit sanding sponge to remove any texture in the painted surface.

4. Mix Paint into Polyurethane

Now here is a tip you won’t hear from a beginner or someone who hasn’t actually applied polyurethane over paint. I highly recommend mixing a few drops of paint into your polyurethane, and I mean a few drops nothing crazy. This is most effective for darker paints, it prevents a cloudy finish in the final results. Trust me, nothing is worst than a cloudy looking finish in your painted project.

Anyway, I add a few drops to all my polyurethane painted projects to ensure the finish looks as good as possible.

Also, it is super important that you only mix water-based paint in water-based poly and vice versa. DO NOT put oil-based paint in water-based polyurethane, it will not properly mix ruining your product. If you have used opposite types of bases, just skip this step.

5. Apply the Polyurethane

My favorite application method is using a paint sprayer, I add my water-based polyurethane and thin at 10%, then I am ready to go. The process is simple and you can see me spray poly in this video here on YouTube.

The other option is using a brush, wiping, or a foam applicator. I would use the applicator, it has proven to give the smoothest results over painted surfaces.

I like to apply 2-4 coats of polyurethane, depending on the paint I am using, if its durable 2 coats of poly will work for me. If not, I will apply more poly coats. You can lightly sand between coats if you want to using a 300 grit sanding sponge, but it isn’t required. Read here if you should sand the final coat of polyurethane.

6. Let it Dry

After applying the desired coats you are finished! Let the piece dry for the night and come check it out in the morning. Do not bother adding the hardware until 24 hours if possible, this just allows time for the polyurethane to harden a bit more so you don’t scratch it easily.

Check out my video below where I use polyurethane over a painted piece of furniture, I go through the entire process. I start applying the polyurethane around the 14:30 minute mark if you’re in hurry:

Applying Polyurethane Over Different Types of Paints (Answered!)

Can You put polyurethane over chalk paint?

Yes, you can put polyurethane over chalk paint, however, the most recommended finish for chalk paint is wax. When I paint furniture with chalk paint I like to use Minwax finishing wax, it is the most commonly used finishing wax for furniture. Wax is great for chalk paint because it provides protection but also preserves the chalky feel to the finish.

Chalk paint is very popular in the furniture painting world, and hey, I can see why. Once you apply chalk paint and let it fully dry and cure, the surface is super durable. Chalk paint has a matte-like finish, the name explains itself, it feels chalky. You can apply polyurethane over chalk paint, which I have before and you will have no issues. It is best to use water-based polyurethane over chalk paints, just because oil-based will turn yellowish and potentially ruin your beautiful paint job.

Can You Put Polyurethane Over Spray Paint?

You can apply polyurethane over spray-painted surfaces, however, spray paint is quite durable already. Depending on the project, you may or may not need the extra protection. If you are spray painting furniture, indoor or outdoors, adding a few coats of polyurethane as protection is a good idea.

When I use spray paint and I want to seal it for protection I will pick up a can of polyurethane too. The best options for painted surfaces that will be kept inside are Oil-based Minwax Poly or Water-based Minwax Polycrylic. If you plan to paint a surface for outdoor use, you can use outdoor paint, but if you are going to seal it I recommend checking out our article on the best outdoor finishes.

Can You Put Polyurethane Over Latex Paint?

Yes, you can put polyurethane over latex paint with no issues. Latex paint is very common, it is water-based and the prices are great. I have used latex paints for many different projects and had no problems applying my water-based polyurethanes over them for protection.

Can I Put Polyurethane Over Acrylic Paint?

Acrylic paints today are water-based paints, however, once dry these paints dry into a very water-resistant durable surface. You can add layer on layer without disturbing the underlying layer, you know what that means? You can use polyurethane over acrylic paint without causing any issue to the surface underneath. It is recommended to use water-based polyurethane over acrylic paints.

Can I Put Polyurethane Over Enamel Paint?

Enamel paints are oil-based paints and are great paints for exterior use because of their great durable features. You can also see them used in high-use indoor areas like kitchen or bathroom cabinets, floors, and also doors. Enamel paint is known to be more glossy than acrylic paints and when a surface is glossy usually a clear coat has a harder time adhering.

If you were to use polyurethane over enamel paint a light sanding with 240 grit or higher is recommended for proper adherence. However, enamel paint does not always need a clear coat because of its high level of durability on its own.

Polyurethane Over Paint Related Questions

Can you put polyurethane over painted concrete floors?

You can apply polyurethane over painted concrete floors, but it is not the most recommended floor finish. It is likely to chip and lose its sheen quickly. Instead, opt for an epoxy concrete floor sealer. You also can just use concrete paint and avoid using a sealer at all, this is a money and time-saving option. Of course, no sealers are best suited for basement or garages that don’t see as much use as daily living areas.

Polyurethane over painted cabinets?

Polyurethane can be used over painted cabinets and often is. However, professional-level cabinet painters often use more durable products when painting cabinets. Why? Cabinets, especially kitchen cabinets are a key source of value for a home and they need to look as good as possible, this means durability is crucial. Polyurethane is strong, but not like other options. The most common paint and finish for cabinets is lacquer, it is super smooth and will last for years.

Don’t get me wrong, polyurethane over painted cabinets is a great DIY solution and if I were to paint cabinets I would spray them with water-based poly because of the easy clean-up and the fumes being less harmful. But I am not a professional cabinet painter, and my results would show when compared.