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How Long Does Untreated Wood Last Outside? (Explained)

You might hardly find a project that doesn’t have the use of wood. Similarly, woods are often used outside of our house. Sometimes, wood is stored outside for a long time. Different types of woods are often used for various purposes, both inside and outside. 

But you might be confused about how long untreated wood lasts outside. However, you must know the consequences of keeping untreated wood outside for a long time. Moreover, learning about the treatment process is necessary. 

Besides, knowing about the disadvantages of using untreated wood outside is also essential. Let’s see details about untreated wood and its effects outside. 

Untreated wood last outside

Generally, untreated wood doesn’t last outside for a long time. Untreated wood lasts from a couple of months to a year. The outside weather and harsh conditions lead to the untreated wood’s deterioration. How long untreated wood lasts depends on the type of wood and weather. 

However, untreated wood can be of different types. Different woods have other properties. Let’s see how long these untreated woods last outside. 

Untreated pine wood:

Pine wood is pretty suitable for use outside. Generally, woods are treated before using outside. Because outside woods often face different weather conditions. Moreover, outside woods are prone to deteriorate. That’s why woods are supposed to be treated.

Pine wood is long-lasting outside if treated. But untreated pine wood is also stronger than other types of wood. Generally, untreated pine wood can last up to 2 to 5 years outside. But eventually, untreated pine wood can get spoiled. 

If there is rain and drastically hot weather, the outside pine wood will not last that long. Otherwise, pine wood can last up to 5 years outside. 

Untreated cedar wood: 

Cedar wood is more long-lasting than pine wood. Even cedar wood can last up to 15 to 20 years outside. But you have to consider whether cedar wood is treated or untreated. If the cedar wood is treated, it can last up to 20 years. 

But if the cedar wood is untreated, it will not last that long. When exposed to outside weather, the cedar wood will be affected. For example, if the area is associated with frequent rain, the wood will be wet most of the time. So, the cedar wood will deteriorate over time. 

So, if the cedar wood is untreated and is in harsh weather, it will last up to five years outside. But if the wood is untreated and in good weather, the wood can last up to 15 years outside. So, the lasting time of untreated cedar wood depends on the weather.  

Untreated oak wood:

Generally, untreated oak wood can last up to 2 years outside. After 2 years, the untreated oak wood will show signs of rotting. If the oak wood is treated and used outside, the wood will last more than 2 years. 

But if you leave the oak wood untreated, the wood will face different weather conditions. Eventually, the wood will start deteriorating. Moreover, the wood will rot more if the area goes through continuous rain or cold weather. 

Untreated oak wood will not last outside more than 2 years. Besides, the lifetime of untreated oak wood depends on the area’s weather. 

Untreated spruce wood:

Spruce wood is not that durable if untreated. If you treat the spruce wood, the wood will last more than 5 years. But if the spruce wood is not treated, it will show signs of rotting. Even untreated wood can deteriorate within 3 to 5 years. 

So, untreated spruce wood can last up to 3 to 5 years outside. Generally, spruce wood is treated so that the wood can be durable. But when the wood is untreated, the wood will not withstand the harsh weather outside. 

How long will untreated wood last outside if painted?

You might know that untreated wood doesn’t last long. So, you might want to paint the wood for protection. But painting untreated wood has advantages and disadvantages both. Generally, untreated wood lasts 2 to 3 years more outside if painted

When you paint wood, the wood must go through some preparation. For example, the wood should be treated and used as a primer. But if you don’t prepare before painting the wood, the wood will not last long. 

The untreated wood can face moisture damage if painted. Though the painted surface will keep the water and moisture from entering the wood, the moisture can bleed inside the wood. Moreover, natural tannins can bleed through the wood. 

So, the untreated wood will deteriorate ultimately. The untreated painted surface can protect the wood from outside weather for 2 to 3 years. But the untreated inside core of the wood will go through deterioration. That’s why treating wood before painting is a must. 

Using untreated wood outside: Things to consider

Using untreated wood outside has both advantages and disadvantages. So, when you use the untreated wood outside, you must consider some things so that the untreated wood can last long. Let’s see what things you have to consider while using untreated wood outside. 


The first thing you must consider is the sunlight in the area where you use the untreated wood. Generally, the untreated wood will eventually damage if the area faces too much sunlight. But if the site is shaded, the wood will not damage quickly. 

Besides, if the area is always shaded and no sunlight passes through, the untreated wood might be close to moisture. So, you must consider the sunlight in the place where you are using the untreated wood. 

Geographical location:

Considering the geographical location is necessary. Because different geographical locations have different weather conditions. If the area has a winter season for a long time, the untreated wood will go through drastically cold weather. 

So, you must consider geographical location before using untreated wood outside. 

Type of wood:

The wood type determines how long the untreated wood will last outside. For example, the cedar wood might last for 15 years in an untreated condition outside. But untreated pine wood will not last that long. 

So, how long the untreated wood will last outside depends on the type of wood. That’s why you must consider the kind of untreated wood. 

Weather condition:

Weather conditions are another critical issue. When you use untreated wood outside, you must consider its durability. If the area often goes through harsh weather, the untreated wood will not last long outdoors. 

But if the weather condition is good, the untreated wood will not be affected much. So, you must consider the weather before using untreated wood outside. 

How to use untreated lumber outside?

Now that you know you can use untreated lumber outside, you might want to see the process. You have to use the untreated lumber appropriately so that the wood doesn’t get damaged. So, let’s see how you can use untreated lumber outside. 


While using untreated wood, you must seal the wood before using it outside. For sealing, cleaning is the first step. You need to clean the wood and dry it thoroughly. Cleaning the untreated wood from dirt, dust, and moisture trapped inside the wood. 

You can eliminate the moisture content by using a dry air process. This process will take 2 to 3 days to dry the untreated wood fully. 

Choosing the sealant:

Now you can seal the untreated wood with an appropriate sealant. The most common sealants are Shellac, lacquer, polyurethane, varnish, etc. You can use any of these sealants. These sealants have different benefits depending on the type of wood you are using. 

So, you have to choose a sealant among these sealants. Moreover, how long the sealant will be durable depends on the application process too. If you can apply the sealant to the untreated wood, you will get more benefits.

Applying the sealant:

Now you can apply the sealant finally on the wood. You can use a regular paintbrush to paint the sealant on the wood. First, apply a single coat on the surface of the wood. Then you have to leave it to dry. 

When the first coat is completely dry, you can apply a second coat. Then you have to leave the second coat for drying. Through this process, you can use multiple coats of sealant. Multiple coats of sealant will make the wood durable. 

Final Thoughts

Untreated wood can be used outside, but it will not last long. Some woods like cedar will last many years without treatment. But most woods don’t last long outdoors without treatment. The untreated wood gets affected by weather conditions, you can also seal the wood for protection.