Ensuring the longevity of your hardwood furniture or flooring really comes down to choosing the right finish. But it can be tricky, especially if you’re not well-acquainted with different finishes available in the market.
If you’re unsure which type of poly is best for your project, I have compared oil vs water-based polyurethane thoroughly so you can apply the right finish for your project.
Water and Oil-Based Poly Comparison Overview
| Oil-Based | Water-Based | |
| Color/Tone | Amber tone | Clear |
| Coating | Thick | Thin |
| Odor | Strong and powerful | Insignificant/ unremarkable |
| Texture | Smooth | Moderately rough |
| Price | Fairly cheaper | Expensive |
| Long-term Indications | Gets darker over time | Remains clear |
What is Polyurethane and its Benefits?
Polyurethane is a known coating material commonly used as a wood finish. Typically, it is a clear liquid that can be sprayed or brushed onto the wood for protection from the elements.
Not only can the poly protect wood, but it also elevates its appearance, accentuating the grain and drawing out that rich golden tone.
While many people tend to compare polyurethane to shellacs, varnishes, and lacquers, what sets it apart is that polyurethane isn’t organic. It’s essentially a plastic and is factory-produced, which differentiates it from many traditional wood finishes.
As shown above, polyurethane is available in two varieties: oil and water-based poly. Each has its own benefits and advantages, depending on the purpose.
Appearance and Finish
The most important thing you need to consider before deciding which type of wood finish to use, especially for your hardwood floor, is how you want them to look. Do you want your flooring to stand out? Or do you want to have your floor as subtle and natural look as possible?
While oil and water-based polys have high-quality finishes and make hardwood floors aesthetically pleasing, the finish looks different.
Oil-based poly has a more subtle tone and naturally looking. Meanwhile, the water-based finish delivers more shine and a stand-out look.
Sheen Levels
When it comes to polyurethane, there are four primary finishes, each distinguished by its sheen level. Here they are, listed from the least reflective to the most:
- Matte Finish
- Satin Finish
- Semi-gloss Finish
- High-gloss Finish
Satin vs Semi-Glosspolys
The flattening paste or also known as zinc oxide determines the light that the polyurethane finishes can reflect. The higher the flattening paste content, the lesser light it can reflect.
Satin polyurethane has higher flattening paste content, so it has lesser shine and a duller finish. On the other hand, semi-gloss polyurethane has lower flattening paste content, reflecting more light and resulting in a shinier finish.
Read More: Satin vs Semi-Gloss Polyurethane
Oil-Based Polyurethane
Oil-based poly uses petroleum or mineral spirits as a base for the polyurethane solids to be carried out. It is a brownish liquid that looks thicker compared to water.
When oil-based polyurethane was first introduced, it quickly became the go-to finish for many of us woodworkers.
When to Use
The preference for oil-based polyurethane among many in our community stems from its chemical and scratch resistance. Based on that, I’d suggest using it for areas that see a lot of activity, like floors, tables, countertops, and frequently used furniture.
What’s also amazing about oil-based polys is the way they highlight the amber hue of the wood, which deepens beautifully over time. With proper care, such a finish can remain pristine for more than a decade.
Oil-based polyurethane is also suitable to use if you want to enhance the color of the wood. It is versatile, with water resistance, so you don’t have to worry even if the wood gets wet often.
Recommended Read: Ways to Make Your Wood Darker
Pros
- It enhances the amber hue of the wood
- It makes the hardwood floor brighter and shinier
- The finish stays longer and more durable
- It protects the wood from scratches
- It requires only one coat or fewer coats
Cons
- It takes a very long time to dry
- It can produce a strong smell
- It tends to get darker over time
Water-Based Polyurethane
This type of polyurethane uses water as a base instead of mineral solvents or oil for the polyurethane solids to be carried out. It looks like a milk substance and has a clear coat when dry. Initially, most flooring contractors avoid using it because it is less durable.
But as technology advances, its durability has improved over the last decade. It is no wonder that many professional woodworkers now prefer water-based vs oil-based polyurethane for their projects.
When to Use
If you’re like me who’s sensitive to potent odors, I’d suggest going with water-based poly since it’s virtually odorless, especially when compared to its oil-based counterparts.
Another advantage of water-based polyurethane finishes is their quicker drying time. They’re a breeze to apply and perfect for projects you’re looking to wrap up in no time.
You can also use it on projects that need thin and flexible coating, especially on hardwoods that you want to look just natural. Meanwhile, you can always adjust the protective coat if you prefer the harder coating.
Check This Article: Recommended Polyurethanes for Stair Treads
Pros
- It produces clear finish
- The drying time is much faster
- The finish does not darken over time
- It doesn't emit strong odor
- It gets harder when dry
- It's easier to apply and clean up
Cons
- It's more expensive
- It need more coats
- It scratches easily
Comparison of Water and Oil-Based Poly
Color
Essentially, oil and water-based polys are very different when it comes to color. So, when you’re choosing between the two, it’s crucial to keep in mind the final look you’re aiming for.
Although it will not matter much for a darker wood, it’s imperative for lighter wood like the light-colored maple.
Oil-based polyurethane produces deeper color, a very yellowish tone or amber hue that becomes darker over time. It’s particularly good for hardwood floors or furniture if you want them to look brighter.
But you may want to avoid using it on a white-washed hardwood floor or gray-stained hardwood as they will intensify and become very dull after some time.
On the other hand, a quality water-based poly has a very clear finish and almost does not affect the color of the wood. So, I’d suggest going for it on woods with beautiful colors and grain patterns you want to preserve.
Recommended Read: Non-Yellowing Polyurethanes to Consider
Ease of Use and Application
Oil-based polyurethane finishes should be applied properly using a brush. It can take longer and more complicated to apply because it’s difficult to achieve even strokes using a brush.
Meanwhile, water-based finishes are easier to apply as they can be rolled on or sprayed on the hardwood.
Durability
Both oil and water-based poly protect the hardwood, especially from scratches and harsh environmental conditions. But they’re not equally durable.
If you want to retain the hardwood finish for much longer, use oil-based polyurethanes. It can be intact for seven to ten years before you must recoat.
On the other hand, water-based polyurethane finishes can only last for three to five years. This means you will need to recoat more frequently to protect the wood. But does water-based poly turn yellow over time? Find out next!
Number of Coats
Oil-based polyurethane floor may require at least three coats to achieve the desired finish. However, you may have to sand the hardwood after applying the last coat. Meanwhile, water-based polyurethane requires more coats, preferably four to five coats.
Drying and Curing Time
Use water-based polyurethane if you need the wood finish to dry faster. It only takes 24 hours before the wood can be used. While it usually takes two to three hours for one coat to dry before applying the succeeding coat.
Also, water-based polyurethanes cure or harden faster. It only takes 14 days for the curing process.
On the other hand, oil-based polyurethane takes 48 hours before it can be safe for use. It takes even longer to cure, at least 30 days before it completely hardens.
Smell
Most DIYers consider smell as one of the important factors in choosing what type of polyurethane to use, especially for a woodworking project inside the house, like hardwood floor.
This is why a flooring contractor prefers water-based polyurethane, as it is very insignificant to completely odorless. Meanwhile, oil-based poly has a very powerful odor that lasts several days and may stay even after it has dried.
Toxicity
Polyurethane has noxious fumes, which can be hazardous if ingested or inhaled. Therefore, you should ensure that your work area is well-ventilated.
Also, there’s a significant difference in their volatile organic compounds or VOCs [1], which determines the type with a higher toxicity level. Between the two, water-based has lower VOCs, so it’s less toxic.
Hardness and Thickness
Oil-based is a thicker poly. However, it is softer, so it is more prone to dents. Meanwhile, water-based polyurethane is thinner, but it has a harder finish. The only downside is it is more vulnerable to scraping and surface scratching.
Changes Over Time
Normally, changes in the wood finish, especially on the light-colored wood, become more apparent after some time. The oil-based finish becomes darker, giving the wood an amber tint.
However, water-based polyurethane may remain clear even after several years, preserving the wood’s natural color.
Price
Between oil-based vs water-based polyurethane, the latter is more expensive, thrice as much as oil-borne polyurethane.
However, water-based poly gives you more flexibility in preserving the wood. It dries faster, so you can finish the work in no time, compensating for its higher cost.
On the other hand, oil-based poly is much cheaper but will take longer to dry. You will also wait for the odor to disappear before using it. So a long waiting time may cost you even more.
Cleaning and Maintenance
Another important factor that you should consider before choosing what type of poly to use in your project is how you can maintain them. Remember that oil poly is more vulnerable to dents, while water-based poly can be scratched easily.
With the right care, your hardwood pieces or flooring can stand the test of time. Here are some tips I swear by to maintain them:
- Clean the wood with a damp cloth regularly
- Avoid applying harsh cleaning chemicals
- Avoid using excessive water when cleaning the wood
- Refinish the wood after a few years
- Use quality products for cleaning
FAQ
Is it okay to apply water-based poly over oil-based stain?
Yes, you can apply water-based poly over oil-based finishes or any type of stain. However, there are a few important factors to consider. First, ensure that the oil-based stain has completely dried and cured before applying the water-based polyurethane.
Additionally, lightly sand the stained surface to create better adhesion for the water-based polyurethane.
How many polyurethane coats should you apply?
Typically, you should apply three coats of polyurethane or more. If you are using water-based poly, apply five to seven coats, especially on wood or surfaces used often.
Can you thin down polyurethane?
Yes, it is possible to thin polyurethane. The paint thinner can make the brush marks and bubbles disappear easier. Although it is not necessary for water-based polyurethane. But it helps the oil-based poly finishes to dry faster and last longer.
How long can a water-based poly last?
Water-based polyurethane can last for five years. But you may need to refinish it after three years to maintain its luster. Ensure to use good quality poly to avoid refinishing sooner.
Is it safe to sleep in a house after finishing surfaces with polyurethane?
No, it is not safe to sleep in a house after finishing surfaces with poly because it releases toxic fumes. You must wait at least 72 hours before you can stay in the room.
Which is better for hardwood flooring?
You must consider the result you want for your hardwood flooring before deciding which type of poly to use. For a more natural look, use water-based.
Oil-based polyurethane is more suitable if you want to highlight the amber color of the wood floors. When applying, make sure to use an appropriate brush for polyurethane for better results.
Conclusion
It is tricky to choose the better finish for your project if you do not fully understand their differences. Therefore, it’s important to learn their pros and cons before deciding.
Hopefully, after reading this comprehensive comparison of water vs oil-based polyurethane, you now have a clear direction to achieve the desired result for your project.
Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You’ve probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.
Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.
