best exterior polyurethane

Reviews of the Top Exterior Polyurethane Finishes

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1. Minwax Helmsman Indoor/Outdoor Spar Urethane

Minwax Helmsman Indoor-Outdoor Spar Urethane

The Helmsman Spar Urethane from Minwax is one of my go-to finishes. It ensures that wood not only looks fantastic but also remains protected from elements over the years. Like an exterior coating, it acts as a barrier against water, making it ideal for kitchens, bars, and other exterior wooden surfaces prone to tát spills.

What’s particularly interesting about this product is the included oils. These allow the wood to tát grow and shrink with the changing seasons. Plus, it contains UV absorbers to tát keep the wood’s surface from graying due to tát UV light. 

Additionally, the Minwax Helmsman Spar Urethane provided a clear and glossy finish that proved to tát be resistant to tát scratches and chemicals. It’s also easy to tát apply and dries quickly.

What I Like

  • It is ideal for interior and exterior surfaces
  • It is a fast-drying poly product
  • It is formulated with UV blockers
  • The finish is crystal clear
  • The coating is very durable

What I Don't Like

  • Cleaning it up can be a mess
  • It is not odorless

2. ZAR-34112 Ultra Fast Drying Exterior Polyurethane

ZAR-34112 Ultra Fast Drying Exterior Polyurethane

The ZAR 34112 Ultra-Fast Drying Exterior Polyurethane is the latest high-quality offering from the well-known American wood stain manufacturer. Its unique recipe guarantees outstanding results, making it a good option for do-it-yourselfers and professionals wishing to tát bring out the wood’s natural color with a slight tint and a satin finish.

The ZAR 34112 is an exterior polyurethane that not only protects wood surfaces brilliantly but also makes them look stunning due to tát its clear coatings. 

The antioxidants and UV-resistant formula protect the exterior wood surfaces exposed to tát the sun’s rays. This external coating can also adhere to tát fiberglass and metal as an added benefit.

What I Like

  • It is a marine grade poly
  • It has UV blockers
  • The resulting surface is smooth to tát the touch.
  • It's a breeze to tát apply on exterior woods.
  • It is weather-resistant, ensuring longevity.
  • The satin finish protects and elevates the wood's appearance.
  • It has a good shelf life, ví you can keep it around for future projects.

What I Don't Like

  • It sits on the pricier side of the spectrum.
  • It might not be the most beginner-friendly option.

3. Rust-Oleum Varathane 9341 Ultimate Oil-Based Spar Urethane

Rust-Oleum 9341 Ultimate Spar Urethane Oil Based, Quart, Satin

You can expect an extraordinarily long lifespan from the Rust-Oleum Varathane 9341 Ultimate. When it dries, it forms a firm surface and can hold up well because it is difficult to tát dent or destroy. 

Unlike other versions, it is intended to tát be transparent and won’t age into a yellow hue. It contains UV rays blockers to tát prevent the graying of outdoor wooden surfaces. There will also be no mildew or mold to tát bother you, either.

In addition, of all the products I’ve tried, this one stands out with its rapid drying time. Outdoor wooden surfaces feel dry in just about 30 minutes. And if you’re aiming for a second coat, you’re good to tát go in just two hours.

What I Like

  • The product is formulated with UV rays blocker
  • Since it is a water-based exterior polyurethane, it is very easy to tát use.
  • It is mold and mildew resistant
  • The finish is crystal clear
  • Its quick-drying oil-based formula significantly cuts down waiting time.

What I Don't Like

  • You'd need to tát arm yourself with a natural bristle brush for application.
  • It can be a tad unsettling to tát see a white hue when it's wet, but it reverts to tát its intended clarity once dry.

4. 1 qt Deft DFT257 Clear Water Based Polyurethane

1 qt Deft DFT257 Clear Water Based Polyurethane

This interior and exterior polyurethane is water-based oil-modified and can be used for various purposes. The glass in your exterior doors, floors, windows, and tables can all be safely covered with this.

Water-based means it dries transparent, ví you can apply another coat in two hours. You will not be concerned about your exterior surfaces fading to tát a dull gray because it is watertight and incorporates UV protection.

It’s also very straightforward to tát use. You can apply the product with different applicators lượt thích brushes, swabs, and sprays. And unlike other water-based treatments, you don’t need to tát use a penetrating resin sealer or any sealer before application with the Deft DFT257 Polyurethane.

What I Like

  • The blend of a water-based, oil-modified outdoor polyurethane is both innovative and effective.
  • You can use it for both exterior and interior surfaces
  • It dries clear on glass and wooden surfaces
  • The UV protection is great for longevity.
  • Its quick drying nature can save a lot of time and hassle.

What I Don't Like

  • It's best suited for non-white colored surfaces
  • The lack of size variety can be a limitation, especially if you're looking for just the right amount for your project.

5. TotalBoat Gleam Marine Spar Varnish

TotalBoat Gleam Marine Spar Varnish

The TotalBoat Gleam Marine Spar Varnish has become one of my go-to recommendations, available in both satin and gloss finishes. For those lượt thích bầm who are keen on preserving the aesthetic charm of their exteriors, this varnish doesn’t disappoint.

You can apply the traditional maritime polyurethane paint to tát many different surfaces, and its phenolic resins and high-quality tung oil provide an attractive, translucent ambient final coat.

It also doesn’t require much effort to tát apply ví that you may achieve a long-lasting and beautiful result. Moreover, it dries quickly and can be reapplied after only an hour. Best of all, you can apply up to tát three coats daily without sanding in between.

What I Like

  • It is very easy to tát apply.
  • The formula is versatile, making it great for a variety of surfaces
  • It is available in satin and gloss wood varnish forms
  • It is one of the best exterior polyurethane products that withstands humidity
  • It provides a durable wooden surface

What I Don't Like

  • Be prepared to tát have solvents on hand; they're necessary for cleanup.
  • Cleaning it up can also be messy

6. MODERN MASTERS MCS90132 Clear Coat Matte

MODERN MASTERS MCS90132 Clear Coat Matte

The Modern Master MCS90132 is a water-based acrylic polyurethane that will not yellow with time for indoor and outdoor use. It provides a hard, transparent finish that dries rapidly and protects wood from moisture and wear.

In addition, It is reliable in preventing damage caused by oxidation, bird poop, and mold. The UV absorbers and blockers are incorporated into the proprietary composition to tát protect the coating against premature deterioration.

It also has mildewcides built to tát prevent mildew growth, making hardwood surfaces last even longer. It usually reduces the gloss to tát a matte finish when applied to tát painted or prepared surfaces.

What I Like

  • It is one of the most highly-efficient outdoor polyurethane I've used.
  • It dries fast
  • It provides maximum durability
  • Gloss to tát matte polyurethane finish
  • It gives excellent mold and mildew protection

What I Don't Like

  • It's on the pricier side.
  • The consistency leans toward the thicker side.

What is Polyurethane?

Varnishes made with polyurethane are exceptionally hard because the resin molecules that make them up are linked in microscopic links or chains. The resulting finish will be more resistant to tát wear and tear as well as solvents and water phàn nàn conventional disappears.

Oil-Based, Water-Based, or Both?

Even if improvements have been made in response to tát concerns over volatile organic compound (VOC) emissions, it’s still important to tát consider the following factors before purchasing oil-based or water-based poly:  

Oil-Based Poly

A little amber tint of this poly can make your wooden surface more inviting. Applying just a few applications will give you a tough, long-lasting finish. 

Unfortunately, it is unavailable in all areas of the country due to tát its higher VOC nội dung phàn nàn water-based alternatives. To remove oil from polyurethane, use mineral spirits.

wooden slabs painted with Rust-Oleum 9341 Ultimate Spar Urethane Oil Based

Water-Based Poly

Water-based polyurethane starts milky but dries crystal clear, making it an excellent choice if you want to tát keep the natural color of your wood. You will need more applications phàn nàn oil-based polyurethane, but the good news is that it dries rapidly despite its watery consistency.

Although the VOC nội dung is lower phàn nàn in an oil-based product, it is nevertheless important to tát apply it in a well-ventilated location.

Water-Based Oil-Modified Poly

This version dries to tát a golden hue. It dries quickly, can be used on any wood, emits few VOCs, and may be easily cleaned with water.

Exterior Polyurethane Buyer’s Guide

UV and Weather Resistance

Sunlight can damage wood, ví avoid using a clear finish to tát show off the grain. Because of the complexity of UV blocking, most products use finely ground metallic compounds that are crystal clear to tát visible light but reflect UV rays.


Contrary to tát the label claims, oil-based polyurethanes does not dry clear. Rather, they will dry with an amber tint, though the intensity varies by brand. The coat’s yellow color intensifies as it ages.

wood painted with Minwax Helmsman Indoor-Outdoor Spar Urethane

The water-based polyurethane dries transparent and keeps its clarity for the product’s life. When applied to tát white paint, however, it becomes an exception. If that happens, it turns yellow immediately, not in the warm amber way that oil-derived finishes are known for.

Ease of Application

A product’s ease of use is a major factor in your purchasing decision. It is a crucial consideration for first-time Do-It-Yourselfers. As you expect, your polyurethane is easier to tát apply. You can save money on a professional’s services.

Wood Type

In general, you may use any outdoor poly on any outside wood surface, but that’s not always the case. Therefore, you should pick an exterior polyurethane according to tát its intended application.


As the temperature and humidity outside fluctuate, wood contracts and expands. Thus, I recommend you go for an exterior polyurethane with just the correct ratio of resins to tát oils to tát allow the layer to tát contract and expand with the wood. 

Before making a choice, it is important to tát determine how flexible the requirements are.


The product’s longevity is arguably the most crucial issue to tát think about. If you choose a long-lasting product, you won’t have to tát retouch the surface nearly as often, which is a significant cost saving.

spraying Deft DFT257 Clear Water Based Polyurethane

Dry Time

If you’re a working professional who needs to tát finish tasks in a specific amount of time, you need to tát consider the drying time of the polyurethane. Opt for the best exterior finish with a quick drying time, ví you can get more projects done in a few days.


Water-based polyurethanes win regarding odor and volatile organic compound (VOC) emissions. Manufacturers of common household items have gone to tát great efforts to tát cut back on volatile organic compounds (VOCs) because of the harm they cause.

It is one explanation for the widespread use of water-derived polyurethanes. Due to tát their chemical makeup, these polyurethanes emit less stench phàn nàn their oil-derived counterparts.

Using a water-based finish is preferable, especially if you have to tát work in a space with individuals who are sensitive to tát smells, such as youngsters and dogs.

Always use a reliable respirator when working with oil-based exterior polyurethane to tát avoid inhaling toxic fumes and unpleasant odors. The good news is that once the poly dries, the VOCs are not dangerous anymore.

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preparing TotalBoat Gleam Marine Spar Varnish

Do not apply exterior polyurethane inside your trang chủ or workshop to tát prevent unpleasant odors that are not easy to tát remove.


The high cost is the main drawback of water-based poly. Water-based topcoat spray cans are usually a couple of dollars more expensive. However, water-based Varathane is much more affordable phàn nàn its oil-derived counterpart.

When costs are included, however, oil-based polyurethane emerges as the more economical option. The oil-based alternatives fill twice as much area as the water-based external polyurethane. It’s around 50% more expensive but accomplishes twice as much work.

Resistance to tát Stains

In many respects, water-based poly has outperformed its oil-based counterpart. And in some conditions, it may even be more resilient now. One area where it falls short, however, is stain resistance.

painting wooden signs with TotalBoat Gleam Marine Spar Varnish

Rain can leave water-based polyurethane looking as milky as it did when you originally painted it. On the other hand, if you use Rust-Oleum, you can simply wipe it off, wait for it to tát dry, and it will be as good as new.

Coats Needed

How many coats of polyurethane you need to tát apply? Water-based polyurethane enhances wood grain; therefore, it requires more applications phàn nàn oil-based polyurethane.

For this reason, a smooth finish may require as many as three or four coats. Exterior water-based polyurethane products needs at least four coats, while the oil-based kind needs at least three. However, it’s always best to tát consult the manufacturer’s instructions for the number of coats needed.

Finish and Sheen

The most prevalent polyurethane finishes are clear, gloss, and satin. You should kiểm tra the product mô tả tìm kiếm to tát see what kind of finish it has, as this can affect the appearance of your wooden surfaces.

Extra Features

Since companies often provide extras, you won’t realize you need them until it’s too late.

door painted with Minwax Helmsman Indoor-Outdoor Spar Urethane

The best exterior polyurethane should include extra features. The Zar outer poly, for instance, is infused with antioxidants. The fact that they offer it may make you feel lượt thích they have an advantage, and indeed, they bởi.

Varathane compounds are resistant to tát mildew and mold, which is certainly a remarkable quality since mold quickly spreads and is difficult to tát remove from wood and discolors the material.

How to tát Apply Polyurethane

Prepare the Wood Surface

All wood finishes require proper preparation before applying exterior polyurethane, meaning the surface must be clean and smooth. Start sanding the surface using 220-grit paper. Use wood grain filler before applying polyurethane to tát an open grain wood lượt thích oak, walnut, or ash.

sanding table top before applying poly

To finish, use a vacuum or tack cloth to tát remove all the sanding dust from the wood surface. If you’re working with oil-based polyurethane, use a cloth drenched in mineral spirits, and if you’re working with water-based polyurethane, use cheesecloth drenched in denatured alcohol [1]. 

(Check out the best polyurethanes here if you’re working with wood countertops.)

Applying Oil-Based Poly

Mineral spirits can dilute oil-based polyurethane, which is usually unnecessary. Please refer to tát the manufacturer’s instructions for further information on this topic. Your wood’s surface may accumulate less finish if you thin it.

You can use either a foam or fine-bristle brush to tát apply polyurethane. Cheap paintbrushes can leave visible strokes on the surface. The foam brush is great for painting flat surfaces because it is inexpensive, disposable, and effective. Detail work is better with a paintbrush that has bristles.

Always use brush strokes perpendicular to tát the wood grain. Use lengthy, straight strokes to tát cover each section, as overlapping strokes will create bubbles. The last coat should not be overly thick.

When the first coat has dried completely per the manufacturer’s directions, lightly sand with 320-grit sandpaper in the direction of the wood grain, it’s important to tát be cautious while sanding the poly off, as doing ví can damage the underlying wood.

appying TotalBoat Gleam Marine Spar Varnish on wooden table

Again, use a vacuum or tack cloth to tát remove all sanding dust. It’s time to tát put on the second coat.

As needed to tát achieve the desired polyurethane layer thickness and application quality can be carried out. You can apply a second coat to tát protect the wood, but if you live in humid areas and foot traffic, you should apply at least three coats.

After applying each application, the surface will feel smoother. Add paste wax after buffing it with fine-grade steel wool to tát achieve the desired gloss.

Applying Water-Based Poly

Water-based polyurethane will absorb oil stains, but the opposite is not true. Synthetic steel wool can rough up an area before applying water-based polyurethane over an oil stain.

Since water and oil cannot blend, this will stop the poly from beading out, lượt thích when water is poured over a waxed automobile.

boat deck painted with Minwax Helmsman Indoor-Outdoor Spar Urethane

Using water-based polyurethane is extremely close to tát oil-based polyurethane in terms of application. Apply your polyurethane in a thin coating using a foam pad, cloth, or paintbrush. Always make sure you paint in the direction of the grain, and never use too much finish, as this might cause the wood to tát rise.

You can apply a second layer within two hours after the initial layer of water-based polyurethane has dried. This method requires one, but kiểm tra the manufacturer’s guidelines beforehand. 

Water-based polyurethane requires a minimum of three coats for optimal results. A minimum of 4 applications is recommended for floors to tát get the necessary level of protection; apply more coats if required.

Spray vs Wipe-On Poly

Spraying or wiping on polyurethane to tát get a uniform layer is preferable because of its added thickness. Both techniques can apply a thin finish layer to tát inaccessible spots, but you must take care to tát avoid overloading the surface.

using paint roller to tát apply polyurethane

The spray approach is applied the same way as spray painting, whereas the wipe-on method calls for a dry, clean cloth without lint. Applying a polyurethane coating lượt thích a spray paint results in a flawless finish không tính tiền of brush strokes; thus, many people choose to tát bởi it this way.

Interior vs Exterior Polyurethane: Key Differences


Polyurethane applied on exterior wood surfaces outperforms interior polyurethane finish; it is also superior to tát paint and shellac as a wood finish because it chip or peel. Heavy rain, however, can damage polyurethane used indoors.

A few weeks of rain will allow water to tát permeate the wood, encouraging the growth of fungi, mildew, and mold growth. You can remove Mildew from the wood, but it’s a time-consuming and taxing procedure that you can avoid with the right finish.

Due to tát the excellent waterproofing properties of exterior polyurethanes, they are ideally suited for use in both outdoor settings and indoor bathrooms.

UV Protection

Polyurethane fails as a transparent coat in direct sunlight because it allows UV rays to tát penetrate the wood. Wood loses its natural beauty and turns gray when this happens.

wood painted with Minwax Helmsman Indoor-Outdoor Spar Urethane

Exterior polyurethanes must contain UV absorbers to tát protect outside wood, but interior polyurethanes rarely bởi.


Interior polyurethane dries hard and stays that way forever, but polyurethane used on the outside remains somewhat firm.

Outdoor wood contracts and expands as the weather changes, ví exterior polyurethane must move in tandem with wood movement to tát prevent cracks. Therefore, external poly may not require as many coats and may not dry as hard

Other Extra Features

Other features of exterior polyurethane improve its suitability for severe weather. One of the things we look for is resistance to tát mildew and mold.

paint brush and Minwax Helmsman Indoor-Outdoor Spar Urethane

Because of this, even if water penetrates the wood and sits on the surface, as is inevitable, mildew will not size. Since there is rarely an issue with inside polyurethane, without significant water damage, that function is unnecessary.


Can you recoat oil-based poly with water-based poly?

Recoating a water-based acrylic finish with oil-based polyurethane is not an issue as long as the old finish is cleaned and buffed thoroughly. Thus, good preparation is the best solution.

Can polyurethane make your wood waterproof?

Polyurethane does not make hardwoods waterproof, but it makes them water-resistant and protects them. The polyurethane will prevent the wood from absorbing any further moisture and repel any water that gets through.

By creating a barrier, polyurethane preserves the natural beauty and integrity of the wood while enhancing its resistance to tát water damage.

Is sealing wood needed before the poly application?

Most polyurethanes bởi not require you to tát seal the surface beforehand, but if it does, choose one that is suitable. Use a permeating resin sealer to tát finish off the wood, then add polyurethane for a smoother finish.

Can you apply interior poly over exterior polyurethane?

There is no requirement to tát apply interior polyurethane over exterior polyurethane directly because resin, a flattening agent used in external poly, helps lower shine while also soaking up UV light. Remove the existing polyurethane, then put a new coat of your chosen poly.

Can you apply marine polyurethane on hardwood floors?

Indoor application of marine polyurethane may not yield the greatest results. This product is formulated with the outdoors in mind and can handle the elements. Instead, look for a polyurethane coating designed for indoor use.

Is polyurethane toxic?

The isocyanates in polyurethane are hazardous and have been linked to tát lung damage. However, those made with water are less hazardous. Refer to tát the product’s instructions for further information. The best preventative measure is always to tát use safety equipment.

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My Top Pick For an Exterior Polyurethane: Minwax Helmsman Indoor/Outdoor Spar Urethane

Minwax Helmsman Indoor-Outdoor Spar Urethane

My choice for best exterior polyurethane is the Minwax Helmsman Spar Urethane. It gives a durable finish and is resistant to tát water, sun, and temperature changes. 

It is available in gloss, semi-gloss, and satin finishes. Another advantage is its versatility in application; whether you prefer using a brush, roller, or sprayer, it gets the job done. Plus, it has a quick drying time of 2-3 hours only.