Have you ever wondered why some wood appears green over time? It happens! That’s why the BarrierBoss team is here to assure you this is perfectly normal. It does not suggest that there is anything wrong with the wood's quality. You may even find that you’ll love the look as it starts to appear. That happens, too!

Despite its green appearance, many homeowners love pressure-treated wood for outdoor projects. Popular uses include:

• Decks
• Fences
• Raised garden beds or garden boxes
• Garden benches
• Porches
• Swingsets 
• Docks

Pressure-treated wood is strong and can resist the growth of algae, mold, and other fungi. It can also withstand some harsh weather conditions. However, many people are surprised when the wood starts to turn green.

What's With the Green Marks on Pressure Treated Wood?

The green marks often appearing on pressure-treated timber are a natural outcome of the wood's treatment process. These marks are created by the copper-containing chemical preservatives used during treatment.

The presence of copper imparts a greenish hue to the wood. Again, this is normal. It is normal and helps prove that the wood has undergone effective treatment to safeguard it against decay, pests, and fungi.

Corrugated Metal Fence In Pressure Treated Lumber 

Green Marks Are No Cause for Concern

We’ll say it again: Green marks are normal on pressure-treated wood. They are not an indication of algae or other fungal growth, and they do not mean that your wood came from a bad batch. These green marks are harmless to you, your pets, and the environment. They do not compromise the integrity or performance of the treated timber.

The green simply results from the copper components in the treatment process.

BarrierBoss: Leading the Way in Treated Wood Solutions

If you notice green marks on your pressure-treated wood from BarrierBoss, there's no need for alarm. BarrierBoss offers premium-grade treated wood. This premium cut and treatment is designed for long-term outdoor use in decks, fences, raised garden beds, garden boxes, and landscaping. 

This wood utilizes a highly developed wood preservative technology. It possesses low VOC (volatile organic compounds) and low ecotoxicity and is certified as an environmentally preferable product. In addition to its great protection, the color pigment technology used in the treatment process leaves the wood with a warm, finished appearance. 

If that’s not enough, we want to inform you that we back our pressure-treated wood products with a lifetime warranty designed to protect against decay, rot, and termite infestation. 

BarrierBoss Pressure Treated Wood 

Common Uses of 4x4 Pressure Treated Wood

4x4 pressure-treated wood is a popular and adaptable choice for outdoor projects such as posts for decking, fencing, docks, raised garden beds, and more. It is specifically treated for ground or freshwater contact. This wood also improves corrosion resistance with exterior metal fasteners and hardware. 

To maintain its appearance and performance, we recommend you follow the "When It's Dry, It's Time to Apply" approach. Apply a water repellent/stain when the wood feels dry after construction. This can help reduce surface weathering and color fading.

Removing Algae from Pressure-treated Wood

It’s important to know that the green marks that we are referring to come from the copper in the preservative and will eventually blend into the overall tone of the wood. They are not algae or fungi. 

However, occasionally, you may find growth on your wood. Treated lumber is less susceptible to rot, but various growths, mold, and mildew can appear. This is most common when your fence or other wood products are located somewhere susceptible to moisture. 

Try these tricks if mold or algae forms on your pressure-treated wood.

• Power Washing: Aim the power washer at the stain and let it do the work. You may need to repeat the process to eliminate the stain completely.
• Scrub with Bleach: Scrub the stain with a bleach solution. Mix one part bleach with four parts water and apply it to the affected area using a sponge or brush. Scrub until the stain disappears, and then rinse with clean water.
• Deck Cleaner: Various deck cleaners on the market are designed to remove stains that are originally from mold or mildew. Follow the manufacturer's instructions and apply the cleaner with a sponge or brush. Scrub the area until the stain is gone, then rinse with clean water.
• Paint over the Stain: If the green stain doesn’t go away after cleaning (or if you don’t like the natural green appearance), consider painting over it. This conceals the tint and offers protection against future staining. Choose a paint color closely matching the original wood color and apply it with a brush or roller. Allow the paint to dry thoroughly before using the surface. Helpful hint: Choose a high-quality, water-based exterior latex paint. Apply a water-based exterior primer before painting.
• Moss and Algae Removal Products: Specialized products from your local hardware store can remove moss and algae from pressure-treated wood. Always read the instructions carefully. Test the product on a small area to ensure it doesn't damage the wood surface before treating the entire piece.

Stained Pressure Treated Wood

What's the Difference Between Treated vs. Untreated Wood?

Treated and untreated wood differ primarily in strength and resistance to weather conditions. Treated wood undergoes a chemical process that infuses it with preservatives, making it resistant to rot, decay, insects, and fungal growth. This can extend its lifespan, especially in outdoor or moisture-prone environments. 

In contrast, untreated wood is natural, without chemical preservatives. This makes it more susceptible to environmental damage. So, it is often preferred for indoor applications or where direct contact with humans and animals might occur (even though treated wood is not harmful to you or your pet). 

Look at the chart below to learn how treated wood compares to untreated wood from the BarrierBoss.

How Long Does Pressure-Treated Wood Last?

Pressure-treated wood is engineered to resist decay, insects, and fungal infection. This gives it a longer lifespan than untreated wood. Typically, pressure-treated wood lasts 10 to 40 years, but this duration can vary quite a bit depending on humidity, rain, temperature fluctuations, and soil contact. 

For a frame of reference, untreated pine varieties last only five to 10 years.

Embrace the Green on Your Pressure Treated Wood 

Remember that green marks on pressure-treated wood are simply a natural byproduct of the treatment process. They are not something to be alarmed about. You can also be confident in our premium-grade treated wood's quality and environmental certifications. 

If green marks have appeared for other reasons, such as algae or mold, you can remove them. Follow some of the tips we shared above for the best results.

Interested in pressure treated wood? Check out BarrierBoss' high quality wood product!

Frequently Asked Questions 

Can I remove the green marks in pressure-treated wood?

Before you grab a wire brush and start scrubbing away, remember that these marks result from the copper-based chemical preservatives used in the treatment process. The result is a greenish tint. Over time, the green will naturally blend into the wood's tone.

However, if you encounter green growths like algae or mold, you can use deck cleaning solutions, power washers, or specialized products designed specifically for removing moss and algae from pressure-treated wood.

What are the green marks on pressure-treated wood?

The green marks on pressure-treated wood are a natural result of the wood's treatment process. These marks occur due to copper in the chemical preservatives used during treatment. Copper creates a greenish hue to the wood. The green tint most often appears along the grain and around knots. Over time, these marks blend into the overall wood tone. Remember that if you see that green color on your pressure-treated wood, it has been treated, giving it strength and protection against decay, pests, and fungi.

Is green pressure-treated wood safe?

Green pressure-treated wood is safe for use. The wood's color does not indicate its toxicity. While concerns about treated wood toxicity made headlines in the past, today’s wood products are significantly less harmful to health. They are strong and can help improve the integrity of your structure.

What happens if you stain pressure-treated wood too soon?

Staining pressure-treated wood too soon can lead to poor adhesion, uneven color, and premature peeling or flaking. The wood's surface may not yet be ready to absorb the stain properly. Pressure-treated wood contains moisture from the treatment process. It needs time to dry thoroughly before staining. This can take weeks to months. Use a moisture meter to test the moisture level and wait for a reading of 15% or less.

Can I paint pressure-treated wood?

While pressure-treated wood is largely considered a finished product after treatment, some prefer the painted look. So, yes, you can paint pressure-treated wood. As we shared earlier in this article, apply a water-based exterior primer before painting. Then, choose a high-quality, water-based exterior latex paint. 

How do you tell if the wood is pressure-treated?

Look for a greenish tint or darker coloration compared to untreated wood. These are tell-tale signs of the preservative chemicals used in the process. Additionally, you may find small slits or stamps on the surface. This simply shows where the treatment was injected. Pressure-treated wood often has a tag or stamp with treatment details. This will include the type of preservative used and why (e.g., "Ground Contact").

Do termites eat treated wood?

Termites prefer soft, rotting, or fungus-infested wood with high moisture content. This often leads to infestations starting in wood in contact with or near the soil. Pressure-treated wood, naturally resistant wood, or composite materials can significantly reduce the risk of termite invasions. 

Pressure treatment involves saturating wood with preservatives under high pressure and embedding these substances deep into the wood fibers. This creates an effective barrier against rot, fungi, and termites. This treatment slows down the wood's natural decay process. It makes the wood stronger and increases how long it will last. 

As a note for our U.S. readers, many U.S. building codes mandate the use of pressure-treated wood in scenarios where wood is exposed to or near the ground. This can help improve protection against pests.

Can you use treated wood indoors?

Using treated wood indoors is possible but with caution. It's best for damp areas, such as basements or bathrooms, or where wood will likely be exposed to moisture. Always ensure the specific type of treated wood is safe for your intended indoor application.

Does BarrierBoss offer a warranty on pressure-treated wood?

At BarrierBoss, we’ve had experiences with manufacturers who don’t stand by their products. We don’t want that for our customers. We’re confident in raising the bar for our treated lumber products. We offer a lifetime warranty. 

However, regular maintenance, including applying water repellents or stain every few years, can help it last longer.