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Can You Use Interior Stain on Exterior Wood Projects?

Using Interior Stain on Exterior Wood


Are you getting ready for a wood project that needs to be stained? If so, it’s critical to understand the difference between interior and exterior stains. Interior stains are normally tailored for indoor use while outdoor stains are specifically formulated with protection from sunlight and moisture in mind. 

To help you prepare, we’ve put together this helpful article that gives insights on staining exterior wood projects. We will discuss what wood stain is, the difference between interior and exterior types of stain, if an interior stain can be used on an outside surface successfully and how to properly apply both kinds of staining products. Let’s get started!

What is Wood Stain?

Wood stain is a type of finish that is used to color wood and protect it from the elements. It penetrates the wood and provides long-lasting protection while also enhancing its natural appearance with an array of hues. Wood stain comes in a variety of formulas, which allows you to choose a finished product that fits your project’s exact requirements. Whether you’re looking for a glossy, matte or transparent finish, wood stain can provide long-lasting protection and enhance the grain of the wood to bring out its best characteristics.

What is the Difference Between Interior and Exterior Wood Stain?

When it comes to staining wood, there are two general categories: interior and exterior stain. Interior stains are commonly used for projects you’re likely to encounter inside the home while exterior stains are formulated with weather resistance in mind and are developed specifically for exposure to the elements.

Interior Stains

Interior stains are ideal for projects such as cabinetry, interior doors and trim. They come in a variety of different finishes, which allows you to choose the perfect one for your project. Whether you’re looking for a glossy finish or something more muted and rustic, there’s an interior stain to match your needs.

Soak Into the Wood

Interior stains penetrate the wood and offer long-lasting protection while enhancing its natural appearance with an array of hues.

Require Poly/​Varnish Afterwards for Protection

Interior stains are not as durable and weather-resistant as exterior stains, so they need to be sealed with polyurethane or varnish for additional protection. These sealants act as barriers to moisture, dust and dirt and will help prevent the underlying stain from fading or discoloring over time. Sealing interior stained surfaces also makes them easier to clean and maintain and helps keep them looking pristine for years to come.

How To Stain a High-Traffic Deck

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Exterior Stains

Exterior stains are ideal for outdoor projects such as decks, siding and outdoor furniture. They come in a variety of colors, hues and finishes, making it possible to customize the look of the project. Unlike interior staining, exterior staining requires no additional topcoat for protection. With proper preparation and application, exterior staining can increase the lifespan of your outdoor projects for many years with minimal care.

Typically Are a Coating with Sunlight Defending Properties

Exterior stains provide superior protection against ultraviolet rays, moisture and insects that can damage or discolor wood surfaces.

Ingredients That Defend Against Sunlight and Moisture

UV Absorbers

Exterior wood stains infused with UV absorbers serve to safeguard wooden surfaces from destructive ultraviolet (UV) rays of sunlight. These specific compounds absorb and dissipate hazardous solar energy and reduce its capability to penetrate and deteriorate the fibers in the wood. The converted energy is released as heat to minimize any potential fading or discoloration that prolonged exposure could cause.

Mold Retardants

Adding a top-notch mold retardant can help protect your wood from discoloration or destruction caused by these organisms. Mold retardants work by creating an unfavorable environment for mold growth through multiple methods such as:

  • Lowering surface moisture levels

  • Shifting the pH level

  • Blocking the development of spores

Mold retardants are a useful tool in reducing the growth of mold and mildew, but it is important to be aware that these products do not provide absolute protection for wood-based materials. Regular maintenance and cleaning should still be undertaken as part of an overall strategy for preserving the integrity of your belongings.

Hindered Amine Light Stabilizer (HALS)

In contrast to UV absorbers, HALS do not absorb ultraviolet radiation, but instead, protect the polymer from deterioration by eliminating free radicals that are generated during oxidation. The self-renewing properties of these molecules make them incredibly efficient — they can consistently regenerate themselves, allowing for long-lasting effectiveness. The cyclic process ensures that HALS never lose their effectiveness or get used up completely.

Can Interior Stain Be Used on Exterior Wood Projects?

Interior Stains Do Not Protect Against the Sun and Moisture Gradients

Interior stains can lend beautiful colors and protection to wood that is not exposed to the elements, yet these same products are unable to effectively protect exterior surfaces from harsh environmental conditions. This means premature fading, peeling and cracking when utilizing interior stain on an outdoor surface. What’s more, it fails to provide sufficient resistance against moisture, mold or mildew damage.

Utilizing the Right Stain for Exterior Wood Projects

Homeowners can select from a range of wood stains in various finishes and colors to keep their wood surfaces looking beautiful and protected. Semi-transparent and solid color stains both provide protection, though they offer different levels of opacity.

Semi-Transparent Stain

ZAR Deck & Siding Semi-Transparent Stain


ZAR® Semi-transparent stains are the perfect way to showcase natural wood grain and texture. With their light pigmentation and thin consistency, these stains provide a translucent hue that enhances your wood’s stunning beauty while still protecting it from moisture, UV rays and other damaging elements in the environment.

Solid Color Stains

Solid Color Stain


ZAR Solid color stains are formulated with a heavier pigmentation and thicker consistency to allow for a deep, opaque coverage that completely masks the grain or texture of the wood surface. This makes them well-suited for transforming a wood’s color or hiding any unwanted discolorations.

They provide exceptional protection against UV light, moisture and other environmental factors that can be longer-lasting than that offered by semi-transparent stains, which makes them ideal for wood surfaces that are exposed to the elements and need a low-maintenance finish.

How to Apply Stain on Exterior Wood Projects

How to Apply Stain on Exterior Wood Projects


Protecting and enhancing the beauty of your outdoor wood surfaces is simple with exterior stain. To get an even finish, make sure you follow the right preparation methods and application techniques. Follow these simple steps to get professional-grade results on your first attempt.

  1. Prepare the wood: Clean the wood surface thoroughly to remove dirt, grime and any loose or flaking material. Allow the wood to dry completely before staining.

  2. Choose the right stain: Select a ZAR high-quality exterior stain that is appropriate for your type of wood and desired finish.

  3. Test the stain: Before applying the stain to the entire surface, test the color and finish on a small, inconspicuous area to ensure it meets your expectations.

  4. Apply the stain: Using a brush, roller or sprayer, apply the stain evenly to the wood surface, following the grain. Avoid applying too much stain in one area to prevent drips and runs.

  5. Wait for drying: Allow the stain to dry completely according to the manufacturer’s instructions. This is typically several hours to overnight.

  6. Apply a second coat: If desired, apply a second coat of stain for added protection and a more even finish.

Adding a Sealer

ZAR Deck & Siding Clear Waterproof Wood Sealer acts as a shield to protect the stain from UV light, moisture and any other environmental factors. It extends the life of your stained wood by preventing peeling, fading and discoloration while also preserving its appearance. In addition, it safeguards against mold growth which can lead to rot and decay if left untreated.

Discover the Leading Interior and Exterior Wood Stains from ZAR

Discover the Leading Interior and Exterior Wood Stains from ZAR


Searching for the perfect stain colors to give your indoor and outdoor wood projects a finishing touch? Look no further than ZAR — our products are designed and formulated specifically to work with all types of wood, including pressure-treated lumber and T‑111. Every time you use them, you’ll get amazing results.

Contact us today for more information and to locate a retail store near you!