Painting Over Polyurethane

Polyurethane is a great product for sealing painted surfaces, especially furniture and cabinets that will take a lot of abuse over the coming years. It should stop the paint from chipping and provide a waterproof barrier. But what should you do if you want to repaint your cabinets or wooden furniture? Can you just paint straight over the surface as it is?

There are quite a few contradictory articles and statements about painting over polyurethane. They start by saying that you can easily paint over polyurethane as long as you do the right preparations to remove the polyurethane from your surface. So, is this a yes or a, no? Can you paint over polyurethane or not?

Can You Use Paint Over Polyurethane?

While there are some forms of paint that you can use over a treated surface, you might not get a high-quality or long-lasting finish. The paint may struggle to adhere, become discolored, or simply peel off following minor contact. Therefore, the best approach is to take away any sealants, varnishes, or other coatings before repainting your furniture or cabinets.

Below are some helpful tips on how to paint surfaces treated with polyurethane. This includes information on sanding and priming surfaces, when you can paint directly onto polyurethane, and some of the best paints to use. By the end, hopefully, you will be able to create the best plan of action to get the ideal result with your next project. 

Why Shouldn’t You Paint Directly Over Polyurethane-Treated Surfaces?

Painting on top of polyurethane isn’t impossible as you will find that different types of paint will work at first to create a decent coat of a new color or a fun design. But it won’t take much for damage to occur. It is very easy to peel the paint away with just a fingernail. So, it won’t take much for the paint to come away with general use or contact. If something were to catch a cabinet door and scrape against it, you could lose the design. The same is true for coffee mugs and other items placed on tables. An extra coat of polyurethane over the top might be enough to prevent this – as long as no damage occurs between painting and sealing the wood.

This option of painting and adding a second coat could work if you only want to touch up existing items with a smaller design. For example, your current cabinet doors or kids’ table may be in good condition, but you like the idea of adding a stencil design. You could clean the surface, apply the paint over the polyurethane coating via the stencil, let it dry, and then carefully add a new sealant. However, you might find that it is better to start from scratch and repaint everything so the whole piece looks fresh. Even if you use the same base color, it could make a difference. 

Painting Over Varnished Surfaces

In some cases, you may have a piece of wood with a varnish coating rather than a standard clear polyurethane sealant. It is important to know what you are dealing with when planning your approach. It is more problematic to paint directly over varnished wood as this can lead to discoloration. Tannins can bleed from the wood, through the varnish, and into your paint. Your fresh coat of white paint won’t stay that way for long.

This is another reason why the safest approach is to strip the wood back and start over. The best way to avoid any issues of adhesion, discoloration, or other factors caused by previous treatments is to remove all traces of them. 

How Long Before You Can Paint Over Polyurethane?

If you want to paint over existing polyurethane, you can do so as soon as it is completely dry. This is important because it ensures that there is a complete protective layer for the base coat underneath before you add the next part of your design. It always helps to work in thin layers and pay attention to drying times, no matter how many layers of paint and sealant you use.

It is easier if you are working on older pieces with pre-existing polyurethane coatings. You can get to work on removing the polyurethane and starting to paint as long as your furniture is clean and ready to work on. Move furniture and detached cabinet doors to a safer space. Take items apart where possible for easier access to the whole surface area. This includes removing any door handles. 

What Products Do You Need to Remove and Paint Over the Polyurethane?

Now we know why it is so important to remove the polyurethane where possible, we need the best tools for the job. This means working in stages to get rid of any problematic coatings and old paint, prep the material, and then add the new color with the best paint for the job.

Is Painting Over Polyurethane Possible Without Sanding?

The first step towards getting your wood in the best condition for painting it is to sand it down. Take it back to the grain and get rid of all the sealants and old paint for a fresh slate. It takes a lot of work as you need to work bit by bit and progress through finer pieces of sandpaper as you get closer to the grain. This will allow for a nice smooth finish. It also helps to have some additional tools like contour grips for dealing with cut-outs, holes, and curves. These can help with furniture legs or intricate carving.

Those that don’t like the idea of using a sander – especially an electric one with all that dust – can try a “liquid sander” instead. This is better known as a deglosser and is a powerful chemical agent that strips the shiny coatings away, such as those sealants and varnishes. It essentially etches into the varnish to create a better texture, which then means that your primer and paint can stick better.

Can You Apply Primer Over Polyurethane?

It is a good idea to apply a primer after you have sanded down your material and removed the sealant. This provides a better surface and a nice uniform base coat for your chosen paint. Some recommended sanding this a little once dry, but it all depends on the finish and presence of brushstrokes. Those that choose not to remove the polyurethane could be OK applying the primer on top. It is certainly more likely to offer adhesion for the paint than using paint on its own.

What Types of Paint Can You Paint Over Polyurethane?

With the wood sanded and primed, it is now time to find the ideal paint for the job. There are lots of different types of furniture paint out there that could prove to be a great choice for your project. However, you need to match the right style to the task. For example, if you want to add a design on top of pre-existing polyurethane, you may be better off with enamel paint. Oil-baed enamel paint should stay in place on a treated surface a little better and you can get some nice little bottles in a range of colors.

Acrylic is a common option instead of oil-based paint because it is so accessible and comes in so many colors. However, you need to be careful when choosing between craft paint and furniture paint. Small decorative elements could be fine with the former, but not for a full coat over a larger surface. Here, acrylic latex paint is a great option, especially for anything that has to deal with temperature changes. There may be fewer color options, but you get a good finish.

The alternative solution here is to go for some chalk paint. You will find guides that say this paint can go over any surface without you needing to carry out all that preparation work. Still, it is a good idea to sand and prime to be safe. Chalk paint always looks great because of the matte finish and you can create some interesting distressed looks that work with the grain of the wood. 

How to Paint Over Polyurethane

Always follow the instructions provided with your chosen paint. Be careful to work in thin layers to allow for better coats and drying times. Find a method that allows for the texture you want, whether that means brushes or using sponges. Be patient with the process and the drying time.

Can You Put Polyurethane Over Paint?

Finally, it is important to give your freshly painted and dry surface a new coat of polyurethane. This will give it the protection it needs to resist damage from contact or water. There is the chance that in a few years’ time you may renovate the room again and go for a new coat of paint – which will mean going through the same long process of sanding, priming, and painting. But there is no point cutting corners here as you may just end up having to repair damaged paintwork anyway.

Some Useful Precautionary Tips When Painting Over Polyurethane

As you can see, painting over polyurethane isn’t the most straightforward task. It is important to appreciate the scale of the job and work through each step properly. Some people will try and find ways to cut corners to make life easier. But, this isn’t a good idea for the following reasons.

1) You should always pay attention to important health and safety considerations

The process from removing the old coating to adding a new one requires lots of products with chemical formulas. Some of these can be pretty potent, so always follow the guidance provided by manufacturers. You also need to make sure to keep the products and any drying pieces away from kids and pets. You don’t want anything getting on their skin or in their mouths. Safety is also important when sanding wood and dealing with the dust. Wear a mask and always work in a well-ventilated area. 

2) You should always let products dry as long as possible for the best results

Drying times are important because you need every single coat to be perfectly dry before moving on to the next element. If you don’t the product may struggle to set and won’t cure properly. Follow the instructions for the primer, paint, and new coat of polyurethane. If you have doubts, wait longer. This could be as much as 72 hours for some paints so avoid using pieces before then. Also, try not to touch the pieces too much to test them as you could smudge the paint or leave fingerprints. 

3) You should always look for the best products within your budget

Finally, there is the issue of cost. It is always important to have a budget in mind for your renovations and to factor in all the different products and materials. But, you also don’t want to go for the cheapest off-brand solution. These may not have the same properties or overall qualities as leading names. In turn, the paint may be too thin, undersaturated, or difficult to apply. Cheaper primers and sealants may not work quite as advertised. 

How To Rejuvenate Furniture and Cabinets with Polyurethane Coatings

There is a lot to consider here if you want the best results. Touching up a polyurethane-coated surface with small stenciled designs isn’t out of the question with a good enamel paint and a new layer of sealant. But it isn’t a good idea to repaint whole pieces this way. Sanding and priming may be time-consuming, but they are worth the effort for the results achieved. Take the wood back to the grain, get it in the best possible condition and build up the appropriate layers one at a time.

Think about the end result and the prospect of having a professional-looking piece of upcycled furniture or cabinetry in your home. The more care you put into painting polyurethane-treated materials the longer you will be able to use and admire them.