Choosing the Best Polyurethane for Outdoor Furniture

Imagine this: you’ve just spent countless hours crafting the perfect piece of outdoor furniture. You’ve sanded it to a smooth finish, and it’s a sight to behold. But wait! Before you set it outside to face the elements, one crucial step is applying the right polyurethane.

Choosing the correct polyurethane for outdoor furniture is about aesthetics, protection, and longevity. It’s about ensuring that your labor of love can withstand the harsh realities of weather and time. It’s about understanding that not all polyurethanes are created equal, and the one you choose can significantly impact your furniture’s durability, weather resistance, and finish.

Understanding Polyurethane

So, what exactly is polyurethane? In the simplest terms, it’s a protective finish that acts as a shield for your furniture. It’s like a superhero’s cape, protecting the wood from the harsh elements, be it rain, sun, or snow.

Polyurethane is a champion in enhancing the natural beauty of wood. It adds a glossy sheen that makes the grain stand out, giving your furniture that extra “oomph.” But more than just a pretty face, polyurethane is tough. It’s resistant to water, heat, and chemicals, making it an excellent choice for outdoor furniture.

But here’s the catch: not all polyurethanes are the same. There are different types, each with its own set of characteristics. Let’s break it down:

  1. Oil-Based Polyurethane: This is an old-school, traditional type of polyurethane. It’s known for its durability and beautiful, warm glow to the wood. However, it takes longer to dry and has a stronger odor than its counterparts.
  2. Water-Based Polyurethane: The modern counterpart to oil-based polyurethane, this type is known for its quick-drying time and low odor. It’s also more environmentally friendly. However, it may not give the same depth of color that oil-based polyurethane provides.
  3. Water-Based Oil-Modified Polyurethane: This type is a hybrid, combining the best of both worlds. It has the durability and warm finish of oil-based polyurethane and the quick-drying, low-odor characteristics of water-based polyurethane.

Why Use Polyurethane for Outdoor Furniture?

You might wonder, “Why should I use polyurethane on my outdoor furniture?” Well, let’s dive into the benefits of this magical substance.

Firstly, polyurethane acts as a knight in shining armor for your furniture, protecting it from the harsh elements. Polyurethane covers your furniture, whether it’s the scorching summer sun, the relentless rain, or the freezing snow. It forms a protective barrier that shields the wood from water and UV damage, preventing warping, rotting, and discoloration.

But polyurethane isn’t just about protection; it’s also about enhancement. It brings out the natural beauty of the wood, highlighting the grain and giving it a rich, warm glow. It’s like applying a filter that makes your furniture look its best.

Lastly, using polyurethane can significantly increase the lifespan of your furniture. By protecting it from damage and enhancing its appearance, polyurethane ensures that your furniture stays looking good for longer. So, is polyurethane good for outdoor furniture? The answer is a resounding yes!

Choosing Between Oil-Based and Water-Based Polyurethane

Now that we’ve established the benefits of using polyurethane on outdoor furniture, let’s tackle the big question: “Is oil-based or water-based polyurethane better for outdoor furniture?”

The answer isn’t as straightforward as you might think. Oil- and water-based polyurethanes have pros and cons; the best choice depends on your specific needs and preferences.

Oil-Based Polyurethane: This type is known for its durability and the rich, warm finish it gives the wood. It’s excellent for outdoor furniture that needs to withstand heavy use and harsh weather conditions. However, it takes longer to dry and has a stronger odor, which might be a deal-breaker for some.

Water-Based Polyurethane: On the other hand, water-based polyurethane dries quickly and has a low odor, making it a more convenient choice for many. It’s also more environmentally friendly. However, it might not provide the same depth of color as oil-based polyurethane, and it might not be as durable in the long run.

Best Brands of Polyurethane for Outdoor Use

Not all brands are created equal when choosing polyurethane for your outdoor furniture. Some stand out from the crowd, earning the trust of woodworkers and DIY enthusiasts alike. Let’s take a look at some of the top-rated exterior polyurethane brands:

  1. Minwax: A household name in wood finishes, Minwax offers a range of high-quality polyurethanes. Their Helmsman Spar Urethane is designed for outdoor use, providing excellent protection against sunlight, rain, and temperature changes.
  2. Varathane: Known for their innovative, high-performance products, Varathane offers oil- and water-based polyurethanes. Their Spar Urethane is a popular choice for outdoor furniture, offering superior UV protection and weather resistance.
  3. General Finishes: This brand offers a range of top-notch polyurethanes, including their Exterior 450, a water-based topcoat with excellent durability and UV resistance.

How to Apply Polyurethane to Outdoor Furniture

Applying polyurethane to your outdoor furniture might seem daunting, but it can be quite straightforward with the right approach. Here’s a step-by-step guide to help you achieve optimal results:

  1. Preparation: Start by sanding your furniture to create a smooth surface. Wipe off any dust with a damp cloth.
  2. First Coat: Apply a thin coat of polyurethane using a high-quality brush, following the direction of the wood grain. Remember, less is more when it comes to polyurethane.
  3. Drying: Allow the first coat to dry completely. This could take anywhere from a few hours to overnight, depending on the type of polyurethane and the weather conditions.
  4. Sanding: Lightly sand the surface with fine-grit sandpaper once the first coat is dry. This helps the next coat adhere better.
  5. Subsequent Coats: Repeat applying a coat, drying, and sanding. For outdoor furniture, three coats are usually sufficient.
  6. Final Drying: Allow the final coat to dry for several days before using the furniture. This ensures the polyurethane has fully cured and provides maximum protection.

Maintaining Polyurethane Finish on Outdoor Furniture

So, you’ve applied a beautiful polyurethane finish to your outdoor furniture. Now what? You’ll need to maintain that finish to keep your furniture looking its best. Here are some tips on how to do just that:

  1. Regular Cleaning: Dust and dirt can scratch the finish over time. Regularly wipe down your furniture with a soft, damp cloth to keep it clean.
  2. Avoid Harsh Chemicals: Cleaning products with harsh chemicals can damage the polyurethane finish. Stick to mild soap and water for cleaning.
  3. Cover or Store During Extreme Weather: While polyurethane protects against the elements, extreme weather can still take a toll. If possible, cover your furniture or move it indoors during severe weather.
  4. Reapply as Needed: Even the best polyurethane finish won’t last forever. If you notice the finish starting to wear or peel, it might be time for a touch-up.

Common Mistakes to Avoid When Applying Polyurethane

Applying polyurethane might seem straightforward, but a few common mistakes can trip up even the most seasoned DIYer. Let’s take a look at what they are and how to avoid them:

  1. Not Prepping the Surface: Skipping the sanding step can result in a finish that doesn’t adhere properly. Always sand your furniture before applying polyurethane.
  2. Applying Too Much Polyurethane: More isn’t always better. Applying too much polyurethane can lead to drips and an uneven finish. Stick to thin, even coats.
  3. Not Allowing Enough Drying Time: Patience is key when applying polyurethane. Not allowing enough drying time between coats can result in a sticky finish.
  4. Skipping the Final Sanding: After the final coat, a light sanding with fine-grit sandpaper can help eliminate brush strokes and give your furniture a smooth finish.

Expert Tips for Weatherproofing Outdoor Furniture with Polyurethane

Weatherproofing your outdoor furniture with polyurethane is smart, but there are ways to make it even more effective. Here are some expert tips:

  1. Choose the Right Polyurethane: Not all polyurethanes are created equal. For outdoor furniture, look for a product specifically designed for exterior use, as these will offer better UV and water resistance.
  2. Apply Multiple Coats: One coat of polyurethane might not be enough to weatherproof your furniture fully. Applying two or three coats will provide a stronger barrier against the elements.
  3. Don’t Forget the Underside: It’s easy to overlook the underside of your furniture, but it’s just as exposed to the weather as the top. Make sure to apply polyurethane to all surfaces.
  4. Reapply Regularly: Even the best polyurethane won’t last forever. Plan to reapply it every few years to keep your furniture well-protected.

Reviewing the Best Polyurethane Products for Outdoor Furniture

When choosing polyurethane for your outdoor furniture, there are several top-rated products to consider. Here’s a closer look at a few of them:

  1. Minwax Helmsman Spar Urethane: This oil-based polyurethane is a favorite among woodworkers for its durability and rich finish. It offers excellent UV and water resistance, making it a great choice for outdoor furniture. However, it has a longer drying time and a stronger odor than water-based products.
  2. Varathane Spar Urethane: Varathane’s Spar Urethane is another excellent choice for outdoor furniture. It’s available in water- and oil-based formulas, so you can choose the one that best fits your needs. Both offer superior protection against the elements, but the water-based version dries faster and has a lower odor.
  3. General Finishes Exterior 450: This water-based polyurethane stands out for its environmental friendliness and ease of use. It provides strong durability and UV resistance, though it might not give the same depth of color as an oil-based product.

Safety Precautions When Using Polyurethane

While polyurethane is a fantastic tool for protecting and enhancing your outdoor furniture, it’s essential to remember that it’s a chemical substance that requires careful handling. Here are some safety measures to keep in mind:

  1. Proper Ventilation: Polyurethane fumes can be harmful, so always work in a well-ventilated area. If you’re working indoors, open windows and doors, or use fans to ensure good airflow.
  2. Protective Gear: Wear gloves to protect your skin, and consider a mask or respirator to avoid inhaling fumes. Safety glasses can also help protect your eyes from splashes.
  3. Safe Disposal: Dispose of used brushes and rags properly. Polyurethane can be flammable, so it’s important to dry these items in a well-ventilated area before disposal.

Frequently Asked Questions

Let’s address some common questions about using polyurethane for outdoor furniture:

How often should I reapply polyurethane to my outdoor furniture?
This depends on the weather conditions in your area and the wear and tear on your furniture. As a general rule, consider reapplying every 1-2 years.

Can I use polyurethane on painted outdoor furniture?
Yes, you can. Polyurethane can help protect the paint from chipping and fading, and give it a glossy finish.

Is it better to spray or brush on polyurethane?
Both methods have their pros and cons. Spraying can be faster and give a smooth finish, but it requires more ventilation and can be messy. Brushing gives you more control and is better for detailed pieces but can be more time-consuming.


Choosing the right polyurethane for your outdoor furniture is crucial in ensuring its longevity and beauty. Whether you opt for an oil-based or water-based product, remember that the key is application and maintenance.

By understanding what polyurethane is, its benefits, and how to apply it correctly, you’re well on your way to owning outdoor furniture that looks stunning and can also stand up to the elements. So, here’s to many enjoyable moments on your weather-resistant, polyurethane-protected outdoor furniture!