You can only ensure that your hardwood furniture or flooring can last if you know what type of finish is suitable for them. But it can be tricky, especially if you’re unfamiliar with finishes.
If you’re unsure which type of poly is more suitable for your project, read this in-depth comparison of oil vs water-based polyurethane prepared by our expert woodworkers.
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.
But it can also enhance the appearance of the wood by highlighting the grain and bringing out the golden tone of the wood.
Although polyurethane is often compared to shellacs, varnishes, and lacquers, the main difference is polyurethane isn’t organic. In fact, it is plastic and factory-made, unlike most wood finishes.
Generally, polyurethane is available in two varieties such as 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
Polyurethane has four types of finishes categorized according to their sheen levels. We list them below from the least to most light reflections:
- 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
The 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.
Oil-based polyurethane was the first to be produced and remained the preferred type of finish of most woodworkers.
When to Use
Most woodworkers favor oil-based polyurethane because it’s chemical and scratch resistant. So, we recommend using it on your floors, tables, countertops, and furniture that you often use.
Typically, oil-based polys bring out the amber hue of the wood that darkens over time. But it could last more than a decade if properly taken care of.
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.
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Pros:
- Enhances the amber hue of the wood
- Makes the hardwood floor brighter and shinier
- Stays longer and more durable
- Protects the wood from scratches
- Requires only one coat or fewer coats
Cons:
- Needs a very long time to dry
- Produces a strong smell
- Gets 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
We recommend using water-based poly if you’re sensitive to strong smells because it’s odorless compared to oil-based products.
Also, water-based polyurethane finishes take a shorter time to dry. They’re also easier to apply and suitable for projects you need to finish immediately.
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.
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Pros:
- Produces clear finish
- Dries faster
- Does not darken over time
- Very low odor
- Harder when dry
- Easier application and clean up process
Cons:
- More expensive
- Need more coats
- 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, it is important to consider the outcome you intend to achieve when choosing between the two.
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, we suggest using it on woods with beautiful colors and grain patterns you want to preserve.
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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.
Whereas water-based polyurethane can only last for three to five years. This means you will need to recoat more frequently to protect the wood.
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 the smell as one of the important factors in choosing what type of polyurethane to use, especially for a woodworking project inside the house, like the hardwood floor.
This is why a flooring contractor prefers water-based polyurethane, as it is very insignificant to completely odorless. While the 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.
But with proper maintenance, your hardwoods can last longer. Below are some tips on how to take care of 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 an oil-based stain?
Yes, you can apply water-based poly over oil-based finishes or any type of stain. But it may not be very effective if the stain is too old already and has fully cured.
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. But oil base 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’ll have a clear direction and achieve the desired result for your project.
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