Can You Apply Water-based Polyurethane over Oil-based? 

Image showing an oil based polyurethane floor

There are two forms of polyurethane formulas that you can use for your wood finish. The oil-based and the water-based one. These two products, whichever you choose will guarantee your wooden structure a much-improved look. The question is,

Can you apply water-based polyurethane over oil-based?

Yes! You can apply water-based polyurethane over oil-based as long as you set suitable conditions for this to happen effectively.

Ensure that you remove dirt, grease, and wax from the surface by scrubbing the surface using a wood cleaner or de-glosser. You can also use mineral spirits

Apply the new water-based finish following the recommendations by the manufacturers. 

The procedure for Applying Water Based Polyurethane Over Oil Based?

The process followed during the application is a simple one and will take a short time as long as you have all the required materials in place. 

We have listed the necessary steps for you to get your job done.

  1. Before you apply your water-based polyurethane over oil-based, ensure that the surface is clean and contains no traces of grease or dirt. Use a detergent or a ball of synthetic wool to clean the surface of the finish if you suspect the presence of dirt or grease on it.
  2. Soon after cleaning your surface, follow it with deglossing. A 120 grit sandpaper does a great job of roughening.
  3. Wipe clean the finish using a tack rag. You can as well use a vacuum cleaner, if you have one, to remove all the traces of dirt that remained after roughening. 
  4. At this point, you have done the necessary preparation by cleaning and deglossing. Feel free to follow this by applying the water-based polyurethane. You can do the application using a sprayer or even a lint-free cotton clothing. 

Once you are through with your applications, allow it time to dry thoroughly, which usually takes up to 10 hours following application.

The Difference Between Water-Based Polyurethane and Oil-Based Polyurethane

You should, by now, know that polyurethane is a protective finish that offers protection to the underneath surface from wear and tear. Both water and oil-based polyurethane do their jobs so well and even share some similarities. However, they have significant differences between them.

Here are some of the differences:

Color: The first noticeable difference between water and oil-based poly is the color. For the oil-based one, you will likely find it in an amber hue color while it’s water-based counterpart is usually clear. This difference makes the water-based formula favorable when it comes to applications where retaining the original color of the surface is paramount.

Initially, it’s hard to tell the difference between the two; however, with time, the oil-based one will begin to exhibit an amber hue that darkens over time. 

Drying times: Another significant difference between Water-based and oil-based polyurethane is the curing time. Oil-based polyurethane takes about 24 hours to dry while water-based one takes only 5-6 hours curing time. 

Smell: Oil-based poly has a strong, pungent smell, whereas its water-based counterpart does not have any odor. 

NOTE: The smell of oil-based poly can be nauseous, and it would help if you stay out of the house while it is drying.

Thickness and Hardness: Oil-based poly is thicker; it is also softer, a property that makes it easier to dent. Water-based polyurethane is, on the other hand, thinner but harder. A water-based poly, therefore, can easily scratch. 

Cost: Cost is the significant difference between these two based and o amazing formulas. Usually, you will find water-based polyurethane almost twice as expensive as the oil-based one. 

NOTE: A lot of people tend to think that water-based poly does not last as long as its oil-based counterpart; it’s not entirely true. These two are durable and will preserve your wooden structures as long as it takes. What’s important is ensuring the appropriate maintenance practice.

Pros/Cons of Applying Water Based Polyurethane Over Oil Based

There are no significant advantages or disadvantages of applying water-based polyurethane over oil-based. However, there is one thing that you need to have at the back of your mind before doing so. There are water-based polyurethanes not suitable for application over lacquer or shellac. 

Another disadvantage of using water-based polyurethane over oil-based is the cost. Water-based poly costs twice the price of oil-based per square foot. 


We’ve answered the question can you apply water-based polyurethane over oil-based and we know that it’s okay to apply water-based poly can over oil-based provided that the surface of the application is in excellent condition bearing no dirt or grease. It is appropriate that you remove all the traces of grease on the oil-based finish using the procedures highlighted earlier on in this article.

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Tyron Otieno

Tyron is an avid woodworker and writer. He founded this website to help other woodworkers, whether hobbyists or professionals by sharing his knowledge and experiencie after a decade of woodworking.

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