can untreated wood be used outdoors, painting a wooden deck

Can Untreated Wood Be Used Outside? (8 Must-Know Things)

Some of us have upcoming projects we plan to get underway.

This could be an outdoor deck or maybe even a shed. We all want to plan properly and use the best material possible to ensure that we have a project built for success and that will last for as long as possible against the weather elements.

While completing some of my own projects over the past few months I began to wonder what my options consisted of. More specifically I wanted to know what options for wood I had (treated vs. Untreated) for my outdoor projects.

As a whole, untreated wood can be used outside. Proactive steps should be taken to make untreated wood a viable option for long lasting projects when used outdoors. Steps such as sealing, painting or using other bonding agents to increase the life of untreated wood.

Let’s take a look into some of the precautions and necessary steps you can cover to make sure your untreated wood can still hold up through the outdoor elements and some other frequently asked questions that commonly arise surrounding this topic.

1. What Risk Can Untreated Wood Pose If Used Outdoors?

If we do opt to use untreated wood, what potential problems will we run into in the future? Most typically when using untreated woods outdoors you are going to run into several potential issues.

Untreated wood becoming wet can be the first problem. This is going to cause the wood to decay, rot, and grow fungus over time. Wet conditions make for a nice breeding ground on untreated wood being used outdoors.

***Untreated wood should still be sealed. READY SEAL WOOD SEALANT will get the job done***


Sun is another potential hazard to untreated wood when used outdoors.  Over time the UV light begins depleting oils from the wood.

A way to battle back against the damage sun can cause to untreated wood is to attempt to only use untreated wood in shaded areas or areas that won’t be directly penetrated by the light.

I have used and tried many methods on our southern facing deck that happens to get hit heavily by the sun all summer long with no shade. Unfortunately, in my case, the only way to keep it looking nice and from deteriorating fast is to treat it or staining it every few years.

The Actual Species of Wood Being Used Outdoors

untreated cedar wood outside

Surprisingly enough, the actual kind of untreated wood you are using for your outdoor project can make a big difference.

Some sealants don’t interact and protect some woods as much as others. The following woods are great for sustaining the outdoor elements for longer periods of time while being untreated.

This is due to the properties blending well with sealants and other forms of commercially purchased protecting agents we all use frequently.

On the other end of the spectrum, using the following woods listed below and leaving them untreated may have completely different results.

  • Alder
  • Pine
  • Hemlock

The woods listed above will lead to further issues when untreated and used outdoors.  They are some of the weakest wood species and begin to experience rotting, decay and weakening more rapidly when battling weather elements and outdoor conditions.

Here’s a great video showing a piece of maple wood experiencing heavy chucking, large cracks and wouldn’t be great to use for any future projects. It’s simply due to aging for 2 years in the elements of the outdoors and being untreated wood.

YouTube video

You also need to be careful with moisture when using untreated wood outdoors.  Especially for decks and other horizontally built projects.

Water tends to collect on these surfaces. When the air temperature is between 32 degrees F and 90 degrees F and you mix in potentially wet surfaces, you are creating a perfect storm for moisture to collect inside the wood furthering rotting, fungus and other forms of decaying wood.

Note: If you’re into wood crafting, you might also want to check out this guide on the best wood for crafts. You will get detailed insights about what type of wood is suitable for wood crafting.

2. How Long Does Untreated Wood Last Outside?

When deciding on which direction to go with my own home projects, I had to weigh in the pros and cons of each option.

A question that popped up for me was how long does the untreated wood last outside? Here’s what I learned.  Too many factors need to be considered to give an exact answer. Considerations such as

  • Sun Vs. Shaded Area?
  • Geographical Location and Normal Temperature Ranges?
  • Rainfall accumulated over the years?
  • Type of Wood Used?
  • Any Sealants or Other Commercially Products Used on The Wood?
  • How Much Ground Contact Does the Wood Have?

Overall, the best answer would be, the integrity of the wood can become jeopardized quickly within a few short years or faster, however, the wood may remain usable for quite some after the fact.

If you are using the wood for projects such as a garden bed, you may be ok with the physical integrity of the wood being impacted.

If you are using the wood for a project such as a backyard deck, this is a completely different story and it would be advised to consider other avenues.

Keep in mind that even some occurrences of using pressure treated wood have shown that decks can become rotting or expiring problems within 10 years or less.

Untreated wood will obviously experience these issues in a much shorter time span.

3. Should You Use Untreated Pine? Can I Use Untreated Pine Outdoors?

Yes, you can use untreated pine outdoors but you shouldn’t make it your first choice.  Pressure-treated pine is going to hold up against the elements much better.  This is due to chemical preservatives.

Treated pine, however, can be a great solution for other outdoor projects including decks or even fences.

So again the simple answer is yes, you may use untreated pine outdoors but don’t have high hopes and expectations for it lasting for a long period of time.

sealing untreated wood outside

4. How Do You Protect Pine Wood Outside?

Thankfully, a few steps are available to make pine for viable for outdoor use.

One of the first and easiest things you do is apply polyurethane finishes. I personally use this polyurethane finish and so far I have been really satisfied.

You can also paint the pine which is going to be a good sealing coat and help protect the wood against the elements.

Be sure that you use a latex or oil-based paint if this is the approach you plan to take. Furthermore, you can also seal your pine with epoxy to provide further protection.

5. Can I Use Untreated Wood For My Outdoor Deck?

Again, yes but it’s not the best approach. You should aim for treated wood.

If you use untreated wood, your woods shelf life will be dramatically reduced. Especially because of the other items we covered previously such as decks typically retaining water easy due to horizontal running boards.

If you have the budget you can always consider using other alternatives as well such as Trex wood. This can get expensive, but it is rising in popularity for projects such as decks.

Speaking of wood types, have you ever wondered about different wood types like parawood, and compressed wood? Check out the articles to learn more.

6. How to Tell the Difference Between Treated and Untreated Wood?

For someone newer to some of these woodworking skills or DIY projects, it may be somewhat difficult to distinguish if the wood you plan on using would be considered pressure treated or not.  One of the biggest things to look for is the green tint to the wood.  Keep in mind over the years when exposed outside the green treated wood will turn brown and real old wood gray.

I have a wooden green treated board walk going through the woods to a lake and it is now going on 25 plus years and still original boards, only a few have been replaced.

outdoor treated wood example

In many circumstances, the wood is also going to contain a marking if it has been pressure treated.  Lastly, you can always smell the wood.

Non-pressure treated wood will smell more natural like the outdoors.

Pressure-treated wood should be easier to pick up on the smell of the chemicals and other additives used to preserve the wood.

7. How Long Will an Untreated 2×4 Last Outside?

This is tough to pinpoint an exact answer due to so many variables.

Some say that untreated 2×4’s can last up to two years before showing signs of rot and others say it can last even longer.

When deciding if you should you use an untreated 2×4 it depends greatly on the application, how much weather and sun it’s exposed to and if it’s making ground contact.

Bonus Tip: Find out where you can get your wood cut to size for your outdoor projects, ensuring the perfect fit every time.

8. The Best Way To Use Untreated Wood – By Sealing It

Sealing untreated wood is an important step to adding life back to the wood and giving it a longer life span when exposed to the outdoors.

Before beginning, you will want to double check if the wood is already experiencing any rot or decay.

Following this step, if everything checks out, ensure the wood is dry.

Once the wood is dry, it’s safe to treat the wood or at least begin the additional steps. To do so, start by cleaning the wood and drying up the remaining water. Following this, the wood needs to fully air dry.

You don’t need to use fans or tools to help aid in the process.  A natural dry is more effective. This is typically going to take roughly 72 hours.

Once you are sure the wood has had adequate time to dry, you can begin applying a wood sealant to the surface.

The wood sealant that I personally like is the Ready Seal Wood Sealant, and I have had good results and always stick with what works for you.

You can use a regular paint brush to apply the sealant.  Repeat the drying process and then repeat a second coat of sealant.  Once you have 2 coats of sealant you can allow to dry a final time.  That would be the final step in the process unless you desire additional coats of the sealant. 2 is typically adequate to protect the wood.

applying sealant to untreated wood outdoors

The Key Takeaways- Untreated Vs. Treated Wood

Overall, when completing any of these outdoor projects. The choice is ultimately yours whether you want to use untreated or treated wood.

You need to evaluate the situation and surroundings that we discussed previously such as UV light, weather, and application of the project.

Overall, untreated wood is never going to last nearly as long for you as treated wood and physical appearance will be jeopardized much sooner.

Ready to start your next outdoor project? Check out our shop to explore a wide range of professionally designed DIY plans.

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