How to Treat Untreated Wood for Outdoor Use

Recently I moved into a new home and it has a huge backyard. It is perfect for so many backyard ideas and wood is my material of choice. Honestly, when looking at prices, treated wood costs a lot more money. However, when looking for long-lasting wood using treated is highly recommended, but in some projects, you could opt-out and use untreated wood and get away with it. Let me teach you how to treat untreated wood for outdoor use!

The best way to treat untreated wood for outdoor use is to apply a wood sealer. Thompson’s WaterSeal is a great choice for large areas like wooden decks and fences, while spar urethane is perfect for outdoor furniture, exterior doors, and various outdoor projects. 

There are a few things to keep in mind from the get-go if any part of your project is going underground just use pressure-treated wood. It isn’t too expensive in the difference. If you place untreated wood in the ground it will rot rather quickly and your project will not be any good. Furthermore, when placing wood underground the best thing to do is surround it with concrete or gravel, but that’s a whole other topic we aren’t getting into here.

Can Wood Be Left Untreated for Outdoor Use?

Wood can be left untreated outside, however, there are a number of factors that make or break it. Where you live and how much precipitation you get is important. When wood becomes wet it is likely to rot faster, which is the reason you should treat your outdoor wood.

Waterproofing is extremely important for any outdoor materials, water mixed with other natural events can cause anything to break down over a period of time.

To answer the question directly, wood can be untreated in small situations and small projects, but be aware that the untreated wood will begin to weather quickly. As an example, I set up six 2×4 pine posts untreated on my patio to hold hanging string lights, the winter has past and they are weathered. The wood is still sturdy and doing what I want it to but the color has changed and it feels softer on the outside.

How Long Does Untreated Wood Last Outside?

Firstly, untreated wood will not last as long as treated wood when put up to the same challenges. Weather mixed with direct sunlight can damage wood quickly and if left untreated it can happen in a matter of weeks.

Untreated wood can last anywhere from a couple of months to over two years. If you are searching for a long-term project you might want to stick with treated wood or make sure you treat it yourself.

What to Consider When Using Untreated Wood Outdoors?

The Risks Using Untreated Wood Outdoors

The major risks associated when using untreated wood is the possibility of rot and other weather related damages. When wood is untreated the water and the sun will damage and decay the wood at a much quicker rate.

If using untreated wood for a fence, you might see the lower portion of the fence decay quickly when it is constantly soaked and especially if its in direct contact with soil. Without a good sealer or protector fences often get full of mildew and end up looking pretty bad. 

When used for decking, the direct sunlight, along with rainwater, will damage its surface causing cracks and possible warping throughout. It’s best to use untreated wood in a sheltered space away from the outdoor elements.

Type of Wood

Realistically, different woods last longer than others. Some types of wood are quite resistant on their own, while others soak up water and rot fast.

When you search for wood at the hardware store you are likely looking for deck wood or fence wood. Other wood projects could be possible too, like outdoor furniture.

Typically, with backyard projects, you are going to buy softwood as the material. They are easier woods for creating decks and fences, while the costs are much lower too. These are typical when buying wood at your local hardware stores like The HomeDepot.

Here are some softwoods that are popular outdoor choices:

  • cedar
  • pine
  • redwood
  • spruce
  • Douglas fir

Here are some hardwoods that are popular outdoor choices:

  • teak
  • oak
  • mahogany
  • walnut
  • alder
  • beech
  • maple

Take a look at the comparison graph below to get a better understanding of the difference between softwoods and hardwoods.

Softwood Hardwood
  • costs less
  • lighter in weight and color
  • treated can last 10 years +
  • untreated can last only a few years
  • more eco-friendly
  • costs more
  • darker in color
  • weighs more than softwoods
  • can last several decades
  • it is naturally weather-resistant
  • less eco-friendly

How to Treat Untreated Wood for Outdoor Use (5 Ways)

The best option to treat untreated wood for outdoor use is through these sealing options. Different oils are an option, applying protective coats are also a preferred method, and it is very easy to order products that include both stain and sealing compounds to waterproof your wood.

Let’s take a look at the best ways how to treat untreated wood for outdoor use:

  1. Outdoor Wood Sealers
  2. Clear Coats -Spar Urethane
  3. Exterior Paint
  4. Wood Oils
  5. Epoxy

1. Outdoor Wood Sealers

Thompsons Waterseal 21801 Gl Wood Protect Voc

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There are many great wood sealers that are super easy to apply. Water sealers are simply a combination of chemicals and oils that have various additions for better UV and mildew protection. The main goal for wood water sealers is to keep the inner wood dry.

I remember growing up with a pool in my backyard surrounded by a wooden deck and fence. While living in Canada we had snow come around every year and we had to keep the wood sealed properly.

My dad, brother, and I would apply Thompson Water seal on the deck surface and the entire surrounding wooden fence after each winter. It held up strong over the past ten years! Of course, some pieces needed replacing over time, but that’s because the pool chemicals damaging the wood.

Best Use for Exterior Wood Sealers:
  • decks
  • fences
  • gazebos
  • wooden exteriors
  • furniture

When you have untreated wood you must treat it with a sealer if you want it to last long. Thompson WaterSeal offers so many options, you can apply their clear topcoat or choose a variety of stain colors too. If you want, check out their options on Amazon by clicking here.

Other great water-sealing options:

Check out my article on the 10 Best Clear Coats for Outdoor Wood to find more options!

How to Apply Water Sealers for Wood?

The easiest way to apply a water-sealer is by using a brush. Other ways you can apply water sealers are through garden sprayers, however, I think the easiest way is through the standard brush depending on the area. In large areas I would highly recommend a paint pad, it is almost like a roller but it’s flat and provides a better sealing finish.

2. Clear Coats – Spar UrethaneMinwax Helmsman Water Based Spar Urethane, Quart, Gloss

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Clear coats are an easy option for some outdoor projects, they can be rubbed on, brushed on, and even sprayed on. When I use clear coats for my outdoor furniture projects on I buy spar urethane and I apply multiple coats for the best protection.


I have used Minwax Helmsman Spar Urethane and it is super durable and waterproof for outside. Many people use this product on some larger projects, which makes it quite reliable on smaller ones no doubt.

I made an outdoor sofa using untreated wood and I used this product to protect it. I am super impressed. It is super easy to apply and it creates this thick coat that seals out water nicely. I have had the piece outside for about a year and it has no mold, rotting, or color changes. I highly recommend checking it out.

Best clear coat products for outdoor untreated wood:

3. Exterior Paint

Worker painting wood with paint brush. exterior wood paint

Paint is always the forgotten way how to treat untreated wood for outdoor use. Simply choose an exterior paint that is waterproof and it’s that easy.

Check out our Top 10 Best Exterior Paints for Wood article here.

I know many people like showing off the wooden look so paint isn’t the best option, but it could look great on certain projects such as:

  • outdoor tables
  • outdoor chairs
  • outdoor fences
  • wooden flower pots or garden boxes
  • and more!

4. Wood Oils

teak oil on teak table prep for sealing and staining

Wood oils are natural ways to protect the wood from rotting and other natural weathering. You can buy decking oil which is created to prevent UV damages and overall weather resistance. However, if treating untreated wood I would go with stronger and more durable waterproof methods mentioned before oils, such as sealers.

The most popular types of outdoor wood oils are:

Read my full guide on the 10 Best Oils for Outdoor Wood Furniture.

Treating outdoor wood with oil?

When deciding what product to use for treating wood outdoors I would recommend choosing one based on the direct project. When using oil I would choose to use it specifically on certain outdoor furniture projects. It provides strong weather resistance with the best natural look.

A common use for oils like teak oil is on boat decks. It provides a beautiful color for that luxury boating experience. Also, teak oil is great for outdoor furniture for the best look and protection. Wondering how long teak oil takes to dry then read our How Long Does Teak Oil Take to Dry? article here.

The biggest issue with wood oils?

Maintenance is a major issue with wood oils. The natural oil may not withstand weathering as much as other options on our list, resulting in re-applying regularly. I know when I apply a product the longer it lasts the better use it is to me. But hey, everyone’s different. Oils do look beautiful and they are simple, which is why they are a good pick.

5. Epoxy

epoxy clear coat tables in warehouse

Epoxy is a polymer that has an extremely strong resistance to liquids. When applying epoxy you are basically applying an ultimate layer of protection against water. Epoxy is thick and will prevent water damage and even surface damages to the wood.

I would recommend a coat of spar or exterior wood oil on the project first, epoxy isn’t UV resistant and will fade over time if outside. Applying a small amount of a UV protector can save the color. Then when it’s all dried up you can layer epoxy over. This provides you with a great looking protected piece!

Epoxy can be a messy way to apply and treat your wood to last, but it could be your top option in certain aspects. I know many outdoor bars that have a nice tabletop fully epoxied for ultimate durability. It is a really nice way to waterproof the wood and make it last for years and years.

Downfall with epoxy as an outdoor finish?

Epoxy can be applied in multiple layers, but with a day of waiting between layers. Also, the worst part is that after you are done applying the epoxy layers it is said that you should let it cure for 4 days or longer.

An epoxy project is very time-consuming when compared to other options on our list of ways how to treat untreated wood for outdoor use.

What Products NOT to Use on Exterior Wood?


Lacquer is a durable and easy to apply finish for wood, I have used it many times on my interior furniture refinishing projects. You spray it on and it dries in no time, that’s the plus with lacquer. However, you may be wondering if it is safe to use on your exterior wood projects? No, never use lacquer on exterior wood, whether it is treated or not. 

Lacquer wood finishes are not designed for outdoor use, yes I know lacquer paint is used on vehicles, but steel and wood are very different materials. Wood loses moisture and can shrink, lacquer is not flexible and will actually come off exterior wood rather quickly compared to an oil-based exterior finish, such as spar varnish. 

Paste Finishing Wax

I actually have a full article on using wax on exterior furniture that you can check out here. However, what you should not use on exterior wood is paste finishing wax. You can buy exterior wax products like Howards SunShield Outdoor Furniture Wax, which is beeswax and orange oil mixed with some UV protection.

Paste finishing waxes, such as Minwax Paste Finishing Wax and Varathane Paste Finishing Wax, are not designed for exterior use. These are used to finish off an interior wood working project, often furniture. The wax is used to protect but can also be used to buff the surface super smooth. 

The reason you should not use paste finishing wax on outdoor furniture is that the wax does not protect wood from the UV rays. Also, water and moisture will damage the waxed surfaces rather quick when compared to other exterior finishes. 

Best Types of Wood for Outdoor Use?

Pine (Most Affordable)

untreated wood pine stacked up

Pine is the most affordable wood for outdoor use, especially when untreated. Pressure-treated pine costs a bit more and lasts longer, but don’t worry because you can treat pine for outdoors use yourself.

If living in dry areas choosing pine could be a bad idea, but why? Well, the dry climate will actually reduce moisture contents in the pinewood, which can warp the pine into an unusable building piece.

Knowing your location and climate is very important when choosing outdoor wood.

Pine will still hold up over time, when left untreated it will probably hold up for a few years still. Although, applying some sort of protection will help keep the wood in better condition from natural events.

Cedar (More Durable)

Patio Chair - Premium Quality Cedar

Cedar is a few steps ahead of pine when it comes to outdoor wood. The price is higher, but you are paying for that jump in quality.

Considering wood maintenance, cedar requires very little. Not everyone takes care of their outdoor items regularly, and choosing cedar is great for those people. You can wash cedar once a year and it will help its overall longevity.

Cedar is much more durable when compared to pressure-treated pine. If not too worried about overall expenses cedar is a great option for you. When considering untreated wood, cedar beats pine easily.

Redwood (Very Durable, but Expensive)

Rain droplets on a redwood deck after the rain

Redwood and cedar are often compared to one another. The thing is redwood is typically more expensive than cedar, it could be anywhere from a few dollars more to twenty dollars, it really depends on the size of wood.

Redwood is known to be slightly better in overall quality, it holds greater strength and is more durable against the weather. Although redwood may seem like the best option if looking for that top-notch quality, cedar is a great budget-friendly option that will still hold up great.

Teak (Great for Outdoor Furniture)

hand holding a brush applying varnish paint on a wooden garden table - painting and wood maintenance oil-wax

Teak wood is used mainly for outdoor furniture, however, you can see it used as a decking too. It is well used as decking on yachts and other boats because of its ultimate weather resistance.

Teak wood furniture is long-lasting and when you buy outdoor wood furniture teak is probably the most popular option, but it still comes at a high price tag.

Teak wood is durable and will last outdoors for many years. If you live in the right place and want a top-quality product, teak is a luxury option that will not disappoint.

Other types of wood for outdoor use?

Treating Different Types of Wood:

How to treat pine for outdoor use?

You can purchase pressure-treated pine that will last a long time. However, when looking to treat pine yourself for outdoor use you have plenty of options. The easiest way to treat pine for outdoor use is to use outdoor wood sealers. When building a pine fence or deck, use a wood sealer for ultimate protection.

While other popular ways to treat pine are using clear coats, such as spar urethanes or lacquer. Clear coats are great for smaller pine projects such as DIY furniture. Don’t forget the easy way of applying exterior paints!

How to treat Douglas fir for outdoor use?

Douglas fir is prone to rotting when in the ground, just like most woods when not pressure treated. The best way to treat Douglas fir for outdoor use is by either painting it or applying a water sealer.

Exterior paint is a great choice when building a Douglas fir fence, and using water sealers are perfect for Douglas fir decks.

How to treat teak for outdoor use?

Teak is typically used for outdoor furniture. The best way to treat teak for outdoor use is using teak oil, however, teak wood is already super weather resistant, its already going to last for decades so teak oil is not 100% necessary. Teak oil will revive the look of old sun-damaged teak.

Treating teak decking you might think teak oil is best, but there is a teak wood natural finish called Semco and any expert would agree it’s the best treatment for weathered or teak in need of a treat.

Sealing teak is different than applying oil, feel free to check out our 5 Best Teak Sealers for Outdoor Furniture, this guide has a lot of good wood sealing information!

How to treat plywood for outdoor use?

Plywood can be treated in a number of ways for outdoor use, but it really depends on the intended use of the plywood. The best universal way to treat plywood for outdoor use is with spar urethane, which will make the wood protected from water, sunlight, and temperature changes. Make sure to apply the clear coat on all corners and edges where water can easily enter the plywood.

How to treat Cedar for outdoor use?

Linseed oil is a popular way to treat cedar for outdoor use, however, an easy option is to find a water sealer designed for cedarwood. These water sealers have the proper oils and protective materials for all types of weathering and mildew issues.

Read my related exterior wood articles: 

Final Thoughts

After answering various questions related to treating untreated wood and what are some ways to treat wood, I hope you found the answer you were seeking. There are many ways to protect wood for long-lasting outdoor usage, but its all about finding what works best for you.

Wood is used in so many ways, from wooden decks, houses, furniture, fences, and the list goes on. In my opinion, I wouldn’t say one option is always better than another. I feel that the best decision is what fits for you personally, this can relate to the cost, the area you live, and the project you are working on.

I hope you found the best solution on how to treat untreated wood for outdoor use!

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