Oil vs. Water Based Polyurethane: Which Is a Better Hardwood Floor Finish?

What’s the verdict on the oil vs. water based polyurethane comparison? Let’s find out which is best for your wood flooring project!

Finishes are considered armors that protect your hardwood floor against moisture and damages as well as improve its appearance.

Most hardwood floor finishes are usually polyurethane which is the most economical finish for DIY applications. However, with two types of polyurethane finishes you can choose from, it can be challenging to pick which one is best for your application.

But no worries! We will be discussing the pros and cons of each and comparing both based on 11 factors to help you decide.

What Is Polyurethane?

Polyurethane is a super-tough synthetic coating made of plastic resin molecule chains that bond together tightly as the coating dries. This creates a highly durable finish that is more resistant to moisture, solvents, impacts, and abrasion than other types of finishes.

Polyurethane can also handle constant traffic which makes it the best choice for protecting wood floors. You can find it in both brush and spray-on formats. Moreover, it is often compared to lacquers, varnishes, and shellacs.

Below is an overview of the differences between these four types of wood finishes:

Type of Wood Finish	Description
Polyurethane	A synthetic finish mainly used indoors and is available in oil-based and water-based options.
Varnish	A UV-resistant finish made from oils, resins, and solvents mainly used for outdoor applications.
Lacquer	Another crystal-clear synthetic finish mostly chosen for creating a glossy surface.
Shellac	The only natural finish made from lac bugs that adds depth and a warm color to the surface.

What Is Oil Based Polyurethane for Floors?

This finish uses various mineral and petroleum solvents to create a higher concentration of polyurethane solids (45% to 50%). With a high solid concentration, it can provide a more durable protective finish in just a few coatings compared to water-based polyurethane. It’s most notable effect is leaving an amber tint which modifies the coated wood’s color.

What Is Water Based Polyurethane?

As the name implies, water-based polyurethane uses water instead of solvents to carry the polyurethane resin. It starts as a milky-white substance and turns into a clear coating once dried. Since it only contains 30% to 35% of solids, you will need multiple coats to create a coating that’s durable enough to protect your floor.

Water Based vs. Oil Based Polyurethane for Wood Floors: Pros and Cons

Let’s continue our comparison by discussing the advantages and disadvantages of each one before we proceed to a more detailed comparison between the two.

Polyurethane Oil-Based

Pros

• Higher solid concentration for more scratch and abrasion resistance
• Better coverage that only requires a few coats (at least two)
• Self-leveling so it smooths out once applied to horizontal surfaces
• Leaves a warm amber glow which makes it ideal for dull woods
• Requires less maintenance and is more affordable compared to water-based polys
• Easy application so you can do it yourself
• Can last up to 10 years

Cons

• Prone to dents
• Dry times can take 6-10 hours for each coat
• Curing times for multiple coats can reach up to 24 hours
• You can’t apply too many coats (more than three) because it is prone to scratching.
• The noxious smell of the final coat can linger for weeks
• Toxic and highly flammable
• You need to sand it before you apply another layer
• You will need chemicals like mineral spirits or paint thinners to clean it up
• Feels sticky when not fully cured

Polyurethane Water-Based

Pros

• Produces almost no odor
• Not explosive or flammable
• Makes your job faster because you can apply multiple coats in a day
• You can apply as many coats as you want
• Produces a clear coating to retain your wood floor’s natural look
• Slightly accents the look of your floor without causing an amber tint
• It dries a lot faster than oil-based polyurethane
• You can easily clean it with warm water and soap

Cons

• Some consider it cold looking
• Makes application harder because of its clear look
• It has a lower solid concentration percentage so you need to apply more coats (3-4 coats)
• Prone to scratches
• You need to recoat every two years
• Twice more expensive than oil based polyurethane

Side-By-Side Comparison: Summary

Here is a summary of the comparison between water-based and oil-based polys based on 11 factors:

	Oil Based Polyurethane	Water Based Polyurethane
Appearance	Amber and will darken over timeLess shine	Clear and will remain clearMore shine
Hardness & Thickness	Thicker but softer	Thinner but harder
Required Coats	A minimum of two coatsUp to three coats only	A minimum of three coatsYou can apply multiple coats
Drying and Recoat Time	6-10 hours between coatsAt least five days before you can replace furniture	2-3 hours between coatsAt least four days before you can replace furniture
Clean-Up	Turpentine, mineral spirits, or paint thinner	Warm water and soap only
Safety	Noxious odorHigh VOCsYou need to vacate the area when applyingThe smell can stay for up to a few weeksNot safe for asthmatic and sensitive people	Low odorLower VOCsMore environmentally friendlyThe room can be occupied while applying the finish
Coverage	45% to 50% solidsMore coverage with fewer coats	30% to 35% solidsLess coverage
Durability	Susceptible to peeling and dentsCan last up to 10 years	Susceptible to scratchesCan last up to 10 years (5-6 years for lower quality ones)
Ease of Application	Easier to apply and repairRecommended for DIYersYou will need a respirator	Harder to apply and correct mistakesOverlapping lines can happen and bubbles can formRequires a professional
Adhesion/Compatible Substrates	Can adhere to almost everything except itself	More versatile (can adhere to almost everything)
Cost	Upfront costs are lowerCheaper if you are going to do it yourself	2-3 times more expensiveHigh contractor prices
Recommended Applications	Dark-color wood	Light-color wood

A Detailed Comparison Between Water & Oil-Based Polyurethane Across 11 Metrics

Now that we’ve given you a summary of the comparison between the two, let us look into a more detailed discussion below and see who wins head to head.

Metric #1: Appearance

Water based polyurethane is clear and will remain clear, making it ideal for keeping your wood floor’s natural color while adding accent to it. On the contrary, oil based adds an amber tone and will become even darker with time.

Some prefer the amber hue produced by oil based polyurethane, but your choice will depend on your own preferences. Also, oil based provides a shinier finish compared to water.

WINNER: TIE

Metric #2: Hardness & Thickness

Oil based is thicker but softer, while water based is thinner but harder. This means that water polys have higher resistance to dents and peeling, but oil polys will have more resistance to scratches.

WINNER: Water-Based Polyurethane

Metric #3: Required Coats

Since water based is thinner, it required a minimum of three coats, while two coats for oil based. Also, you can have unlimited coats with water based polyurethane, but you can’t do this with oil based options. This is because oil based polyurethane finishes are prone to chipping or scratching after a few layers.

WINNER: Oil-Based Polyurethane

Metric #4: Drying and Recoat Time

Considering that the conditions are equal (humidity, temperature, etc.), oil based polyurethane drying times can take 2-3 times longer compared to water based polyurethane. Water based can take only 2-3 hours to dry after each coat, while oil based will take 6-10 hours.

Thus, you can apply all of the required coats (up to four) for water based polys in one day. For oil based, you can only apply one to two coats in 24 hours. Overall, you can replace furniture after four days for water based and at least five days for oil based.

WINNER: Water-Based Polyurethane

Metric #5: Clean-Up

Oil-based finishes require you to use strong-smelling hydrocarbon solvents such as mineral spirits, paint thinner, and turpentine for cleaning. These substances can cause negative effects on your respiratory health if you inhale them in high concentrations. On the other hand, warm water and soap are enough to clean water based polys.

WINNER: Water-Based Polyurethane

Metric #6: Safety

High-quality water-based polyurethane will contain little to no ingredients that are considered by the OSHA as hazardous chemicals. Good quality ones, on the other hand, will have lower volatile organic compounds (VOCs).

Moreover, water based options are safer to apply without needing a respirator because they don’t stink that much. They are safer for people and you don’t need to vacate your house while applying the finish.

For oil based polyurethane, it is made of toxic and highly flammable solvents that are dangerous to the health. Thus, it has a higher VOC content. You will be exposed to harmful fumes during the long drying time and the smells can settle into clothing, curtains, rugs, and bedding.

That is why oil-based poly is not recommended if you have a family member suffering from asthma and other sensitivities.

WINNER: Water-Based Polyurethane

Metric #7: Coverage

Since oil based polys have a higher solid concentration (45%-50%), they provide better coverage in just 2-3 coats. Water based polyurethane only contains 30%-35% of solids, so you will need to apply 3-4 coats (even more).

The solid content of polyurethane finishes determines the hardness of the protective layer the finish can provide. This means that oil-based will provide more coverage and protection compared to water-based.

WINNER: Oil-Based Polyurethane

Metric #8: Durability

Again, the durability can vary depending on the percentage of polyurethane the finish contains. High-quality products have a higher polyurethane content and thus, are more durable but more expensive.

Although oil-based polyurethane finishes have been the standard in the past years, water-based options were able to catch up through better formulations. Both oil-based and high-quality water-based polyurethane finishes can have the same resistance to damage-causing factors. Both can even last up to 10 years, but lower quality water based products can only last up to six years.

However, take note that the longevity of your finish will still depend on how you maintain and care for it.

WINNER: TIE

Metric #9: Ease of Application

Both types of poly finishes come in spray and brush on options. But while oil based poly is easier to apply compared to water based ones, finishing the application of all layers takes longer.

Water based poly can be challenging to apply due to the following reasons:

• Risk of bubbles and overlapping lines due to fast drying times.
• Hard to repair mistakes once it dries.
• Uneven coatings because of the translucent finish. (Although marking each coating’s end can help to know where to begin the next stroke.)

Therefore, you might need to ask for the help of a professional for the application.

Likewise, an oil based polyurethane is easier to apply because:

• The amber hue makes it easier to trace your strokes for a smoother and more even surface.
• Easier to repair imperfections like missed spots due to its longer drying time.

Thus, oil based polys are more recommended for DIYers. But again, they are smelly and produce harmful fumes, so will need to wear protection like a respirator mask.

WINNER: Oil-Based Polyurethane

Metric #10: Adhesion/Compatible Substrates

Water-based polyurethane finishes are more versatile compared to oil based options. They can bond to almost everything like non-ferrous metal, wood, stone, carbon fiber, and cement. On the other hand, an oil based poly can adhere to almost any surface except itself. This is why sanding between coats is required to improve adhesion with the next layer.

WINNER: Water-Based Polyurethane

Metric #11: Cost

The upfront cost of high-quality water based polys can be 2-3 times higher than oil-based ones. Below are the estimated costs for water and oil-based polyurethane finishes according to CostOwl.com:

• Oil-based polyurethane: $40-$80/gallon
• Water-based polyurethane: $20-$40/gallon

However, the cost for using oil-based options can match that of the initial price of water-based ones if you will be hiring a contractor. But if you will be applying the finish yourself, oil-based finishes are your most cost-effective options.

WINNER: Oil-Based Polyurethane

FINAL SCORE

We added one point for each win and included the two factors that the two have tied in: appearance and durability.

As you can see, water-based won by one point, but it is still hard to say which one is really better. Not all people will have the same preferences, so your scoring rubrics might differ from ours.

Recommended Applications

If you still haven’t decided which polyurethane finish to use, then the recommended applications of each type might be able to help you decide:

Oil-Based Polys

• For providing a more durable protective layer to wood floors if color changes do not concern you.
• For high-traffic areas that are prone to heat and moisture or exposed to solvents.
• If you want a rich, honey glow on your wood floor like maple or white oak.
• For yellowish or darker types of wood.
• If the room has plenty of ventilation or when no people will occupy it during the curing process.
• For homeowners (not for condo or apartment buildings because of long drying times and strong smell).
• Other possible applications include cabinets, countertops, and railings.

Water-Based Polys

• For moisture-prone areas as well as light to moderate-traffic areas.
• If you don’t want to deal with odorous solvents.
• For light-colored types of wood (e.g. white-stained, gray-stained, and white-washed) to highlight their natural features without changing their color.
• Looks best on yellowish tones like Fir, Pine, Maple, and Ash woods.
• If you want a fast-drying wood finish.
• For areas with minimal ventilation like basements.

A Few Tips When Using Oil or Water-Based Polyurethane

Let’s end our comparison with some tips that might be helpful to you:

Before Applying the Finish

• Never shake the can to avoid the formation of bubbles that can show up in the final finish. Gently stir it instead.
• Ensure proper ventilation when you are applying the finish.
• We recommend sanding your bare wood floor first before applying polyurethane finishes to remove dust nibs and bubbles. This avoids dust nibs/bubbles from getting trapped in the lower coats.
• Remove dust after sanding using a HEPA-grade vacuum.
• Remove the remaining dust by using old rugs dampened with mineral spirits (make sure to use gloves).
• Put painter’s tape on areas that you want to protect from the finish like walls, edges, and large items you can’t remove.

While Applying the Finish

• Use gloves (chemical-resistant, nitrile, or rubber).
• Apply a minimum of three coats if you have large pets (whether you are using oil-based or high-quality water-based poly).
• Better apply to flat surfaces to avoid runs or drips. In case you do encounter drips or runs, try sanding them out.

Read more on how to apply polyurethane to wood floors here.

After Applying the Finish

• Check the result with a bright light each time you apply each coat to correct any imperfection before the coat dries. The reflection of the light on the surface can highlight imperfections like spots, brush marks, bubbles, and bumps.
• Place throw rugs in high-traffic areas and vacuum or sweep your cured floor often to prolong the life of the finish. It is also best to keep the nails of your pets trimmed if you have any and avoid shoes, especially high heels.

FAQs

The Verdict: Which Is the Best Polyurethane for Floors?

In our oil vs. water based polyurethane comparison, water-based has won by one point based on our metrics. But, the choice will still depend on the final look you want, your desired performance, and how fast you want to finish your project. Not all have the same tastes and living conditions, but an experienced wood flooring contractor can help you find which best suits your needs.

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