The outdoor space is characterized by fluctuating and extreme weather conditions like UV radiation and freezing temperatures. Such conditions can be damaging to furniture and other wooden items outdoors.

This is why we have exterior grade fabric and pressure treated wood for outdoor use to withstand the elements. But in the absence of such treated lumber, can you use non pressure treated wood outside?

This piece seeks to answer the question about using untreated wood outside. It also explores the risks of using such wood outdoors, suggests alternatives, and offers ways to treat untreated wood for outdoor use.

Can You Use Non Pressure Treated Wood Outside?

Yes, it is entirely possible to use non-pressure treated wood outdoors. However, this is not recommended as the volatile outside weather can quickly damage the wood irreversibly, so it is always best to protect the wood when using it outside. 

There are numerous measures you can take to ensure the non-pressure treated wood remains durable even as you use it outside. This article will walk you through the measures and techniques available, so read along. 

How Long Does Non-pressure Treated Wood Last Outside? 

Non-pressure treated wood typically lasts 5 to10 years outside based on the weather conditions in the location, sun exposure, and how well it is maintained.

Poor maintenance can cause untreated wood to last even less than 5 years based on the weather elements it is subjected to. However, protective measures such as those in this article can prolong the lifespan of non-pressure treated wood to more than 10 years. 

On average, pressure-treated wood still tends to be more long-lasting outdoors, often boasting a service life of about 15 years.

Related post: How Long Does Pressure Treated Wood Last?

The Difference Between Pressure Treated and Untreated Lumber  

The main difference between these two wood types is that pressure-treated wood has chemical preservatives infused into it under special conditions of temperature and pressure.

These chemicals make it resistant to insects, water, and UV radiation. In contrast, untreated wood is in its natural condition.

Exposure to moisture or water will cause water to penetrate its pores and make it rot. It is also vulnerable to the sun’s ultraviolet radiation, which causes wood to lose its color. Insects may also feed on it. 

Not all wood species are equal, though. Some non-pressure treated wood will resist the elements better due to their natural resilience and weather resistance.

For instance, teak contains natural oils in its structure, making it resistant to insect and water damage, so you can use it outside, and the weather exposure will not affect it. 

The chemicals used in treating make the pressure-treated wood on concrete more resistant to the elements than untreated wood overall.

Still, you can always apply topical treatments to non-pressure treated wood to make them usable outdoors. These topical preservatives can seal the wood and prevent moisture damage, insect infestation, and sun damage. 

Remember, burning treated lumber is not recommended due to the release of harmful chemicals and toxins. Treated wood contains preservatives that can pose health risks when burned. Use untreated, properly seasoned wood for safe wood burning.

Risks of Using Non-pressure Treated Wood Outside

If you use non-pressure treated wood on exterior applications without applying any topical treatments, the wood will be exposed to various weather elements likely to damage it. Here are some of the risks that such wood may face.

UV radiation 

Part of the beautiful sunlight is the sun’s ultraviolet rays that cause undesirable radiation. Keeping your untreated wood outdoors leaves it exposed to these rays, potentially leading to fading.

The wood’s natural color is often beautiful, but sun exposure can cause the wood to lose that color and become faded. While fading, the wood loses its natural oils, usually responsible for its beautiful and structural support. 

So it is not just the color that your wood will lose, but also its strength.

Water damage

Water is top on the list of things posing the greatest risk to untreated wood outdoors. Whether it is from rainfall, snow, or precipitation, water can leave immeasurable destruction in its wake. 

Natural wood has pores in its structure. Water can enter these pores, and wood rot and decay can ensue when that happens. Rotting and decaying can quickly destroy the structural integrity of the wood, leading to total loss of that wood. 

This is why it is usually crucial to treat wood when using it outdoors. Treatments such as sealants, exterior wood stains, oils, and paint help close the pores in the wood, making it impervious. This way, water cannot enter and damage it. 

Discoloration from molds and mildew 

Dust and moisture are the ingredients that cause molds and mildew to thrive. These fungi can live on the least amount of dust and moisture from the air.

This is why you may see black spots form on your wooden furniture or some other wood items left outside untreated. 

Unfortunately, discoloration never ends there. Once mold infestation begins, wood rot is always lurking behind, eventually causing decay and permanent wood damage.

Reduced lifespan 

All the weather elements outdoors that violate the wood’s structural integrity eventually reduce its lifespan. 

This explains why wooden furniture that is well taken care of will last longer than one that is left outside untreated and improperly maintained. 

Insect damage 

Insects such as termites feed on wood and can quickly damage your precious untreated wood if left outside. 

Pressure treatment usually introduces chemicals that repel these pesky insects. However, untreated wood is completely vulnerable and can be a low-lying fruit to hungry termites in your garden.

How to Treat Untreated Wood for Outdoor Use 

The risks of using non-pressure treated wood outside should not keep you from using one anyways. All you have to do is seal the wood in one of the many ways available. 

This section provides the steps to follow when weatherproofing non-pressure treated wood. 

Tools and materials needed 

Steps to follow 

The steps in this section should apply to any wood and sealant, whether you choose an oil like linseed or Tung oil, a clear coat like polyurethane and varnish, or stain-sealant combos like Ready Seal exterior deck stain and sealant.

Before treating the wood, always ensure it is sound, with no initial or advanced signs of rotting. 

Step 1. Clean the wood 

How you clean the wood will depend on the condition it is in. If it is covered in dirt and grime or sticky stains, you will need to wash it with soap and water, using a sponge saturated with soapy water to remove all the dirt.

Once done, rinse the wood with clean water and let it dry thoroughly before proceeding to the next step. If it is just slightly dusty or dirty, you can wipe it with a damp rag and let it dry. 

Step 2. Sand the wood

Using water on wood for cleaning often raises the grain wood. Once the wood is dry, you should notice some roughness that can show through the finish. 

So, grab sandpaper and sand the surface until it is smooth to the touch. You can use 180 to 220 grit sandpaper depending on the project, the wood you are using, or the sealant you have chosen.

You can also use an orbital sander if you have a big project such as a deck or just a sanding sponge if it is a small project, like a wooden plank. 

After sanding, wipe the surface with a tack cloth or damp rag to remove the wood dust. This will also depend on the size of your project. 

Step 3. Apply your sealant 

After the wood has dried completely, follow the instructions on the label to apply the product to your wood. The recommended application method should be in the manual; ensure you follow all the directions.

Step 4: Apply subsequent coats 

In most cases, your project will need more than one coat of the product for adequate protection. So allow the first coat to dry for the recommended time or longer, depending on the weather, and then apply the second coat. 

If the manufacturer recommends three coats, ensure you let the second coat dries completely before applying the final one. Then let it cure before putting it to use. 

Related read: How to seal cut pressure-treated wood.

How to Tell the Difference Between Treated and Untreated Wood?

You could be aware of the benefits of pressure-treated wood but not know how to identify if the wood is treated. Knowing the difference between pressure-treated and untreated lumber can help you avoid using the wring wood outdoors and risk damaging your project. 

To identify pressure-treated wood, look for the tint associated with the chemicals used in pressure treatment. Treated lumber can have a green or brown tint that it acquires during the treatment.

Manufacturers usually include stamps or end tags identifying the chemical used in treating the lumber. These tags should help you identify the wood. 

Alternatively, observe the smell. Pressure-treated wood should give off some chemical or oily smell. This is much different from non-pressure-treated lumber, which carries a characteristic natural scent. 

The natural scent of wood is typically pleasant, which should be a key pointer in the right direction. 

Which Wood Species Can Be Used Outdoors?

There are a few untreated wood species for decks that do not require pressure treatment to withstand the elements. Often, these wood types have natural chemicals in their structure that make them resistant to the elements. 

Such wood species include 

  • Teak
  • Redwood
  • Cedar
  • Cypress

While these wood species do not require pressure treatment, topical treatments are always necessary to prolong their lifespan and keep them looking pristine for longer.

How to Use Non-pressure Treated Wood Outside

A few preventive measures can help minimize the risks that non-pressure-treated lumber faces outdoors. Here are some things you can do to use non-treated wood outside safely. 

Keep it sheltered from direct sunlight

We mentioned that the sun’s ultraviolet radiation could cause wood to fade and become structurally weak. 

Therefore, you can minimize that risk by keeping the wooden item sheltered from direct sunlight to minimize sun exposure and the related damage. 

Keep it dry

Water is the main cause of wood decay and rot. You can prevent that risk by wiping away any spills as soon as they occur on the wood or covering the wood with protective fabric so that rain does not fall on it. 

Make it seasonal

If you have wooden furniture consisting of non-pressure treated wood, you can bring it inside whenever it is not in use, such as during the fall, spring, or winter months. 

Protect it with chemicals 

The ultimate way to protect your treated wood is to seal it with topical chemicals laden with UV blockers. To do that, ensure you follow the procedure we have given above. 


Can you use non-pressure treated wood for a deck?

You can build a deck using untreated wood, but ensure you seal the wood with stain-sealant combos or coat it with exterior grade paint to make it resilient to the harsh weather elements outside. 

Do you have to use pressure-treated wood outside

It is necessary but not compulsory to use pressure-treated wood for all outdoor projects. The treatment is only necessary for wood types that are not naturally resilient against insects and water damage.

How to make wood last outside

You can make wood last outside by applying linseed or Tung oil to protect it while enhancing its color, sealing it with polyurethane, lacquer, varnish, or finishing and waterproofing it simultaneously with a stain-sealant blend. Remember, waterproofing pressure-treated wood can further enhance its longevity and protection against moisture-related issues.

Can I use common board outside?

While you can use natural weather-resistant lumber outdoors, it can become susceptible to decay at some point. So it is best always to add water-repellent preservatives, exterior-grade paint, or sealer to make it properly resistant to the elements.

Can I use untreated wood outside if I paint it?

Yes, painting is among the methods of weatherproofing wood. So you can use painted wood outside without problems as long as the paint contains UV protection. 

How long does untreated pine last outside?

Different varieties of pine have a projected lifespan of only 5 to 10 years outside. This is pretty little compared to untreated redwood, which boasts a projected lifespan of 50 years or longer when exposed to weather elements. However, note that treating pine for outdoor use extends its projected lifespan.

How long will untreated oak last outside

Oak will last about 15 to 20 years outside if it is in contact with the ground and the soil is humid. But if the oak wood stays above the ground or on a dry site, its lifespan can almost be indefinite or up to 50 years.

Next read: How long does treated wood take to dry?


So, can you use non pressure treated wood outside? We hope this article helped answer this question in detail. 

Indeed, you can use non-pressure-treated lumber outdoors as long as you apply protective oil such as linseed or Tung oil to the wood’s surface or treat it with a suitable outdoor wood sealer.

You can also paint the wood with exterior grade paint to make it resistant to outside elements. Otherwise, using untreated wood outdoors without weatherproofing can be a bad idea as the wood will have a significantly reduced lifespan.

Now that you’ve learned about using non-treated wood outside, it’s time to learn if you can use pressure-treated wood indoors.