How To Treat Rough Cut Lumber For Outdoor Use (4 Easy Steps) | House Grail (2023)

Rough-cut lumber is an excellent option for someone looking to cut down on the price when buying lumber in bulk. Of course, with the lower price, this type of wood has some downsides. It lacks finish and is not as resistant to water and other elements, so you will need to treat it. Once you do the necessary treatment, you can use it outdoors the same way you use commercial wood.

If you’re wondering how to treat lumber for outdoor use, we’re here to help! We’ve developed a step-by-step guide for treating rough-cut lumber for outdoor use below.

How To Treat Rough Cut Lumber For Outdoor Use (4 Easy Steps) | House Grail (1)

Before you begin

There are some important things to consider before you begin. You should use protective gloves, goggles, and a mask when treating the rough-cut wood. Also, it’s best to process the wood in a well-ventilated area or do it outside because there may be some toxic fumes.

1. Sand the wood

First of all, since the wood is rough-cut, you will need to sand it. It’s best to use an electric sander to achieve a good look and do the job faster. Use 100 grit or 120 grit sandpaper on the power sander. Of course, you can use regular sandpaper, but that will take far more time and effort. This step is essential because you can jeopardize the rest of the process if you don’t sand the wood properly. So, take your time with this part of the project, and be as thorough as possible.

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How To Treat Rough Cut Lumber For Outdoor Use (4 Easy Steps) | House Grail (2)

2. Clean it up

Once you’ve sanded all your rough-cut lumber, you will need to clean it. Sanding creates a lot of dust, and since the lumber is rough-cut, it might have dirt and dust stuck on it. Take a clean, slightly damp cloth to clean the wood. You can also use a pressure washer if you’re doing the job outside. The important thing is to leave the wood to dry properly before you proceed to the next step.

3. Stain the wood

After cleaning, you can now stain the lumber. For this part of the project, it’s best to use a paintbrush and to have a cloth nearby to wipe off any excess stain. There are plenty of different stain options on the market so you can choose a wood stain of your preference. Still, since you’re treating the wood for outdoor use, it might be best to choose a water-resistant stain for the best effect. Apply one coat of stain, and allow it to dry out, preferably by leaving it for several hours. To be on the safe side, repeat this step and add a second coat.

4. Apply wood varnish

Last but not least, you should apply wood varnish to the lumber. Wood varnish is used to prevent scratches and abrasions. It will also make the wood more water-resistant, which will benefit outdoor usage. Once you finish, allow the varnish to dry and sand the wood one more time. Apply two more coats of varnish, and you have completed the treatment.

How To Treat Rough Cut Lumber For Outdoor Use (4 Easy Steps) | House Grail (3)

Other Methods of Treating Rough Cut Lumber for Outdoor Use

Other than the steps we mentioned above, there are several other methods people use to treat rough-cut wood. These are some of the most common ones:

1. Outdoor Wood Sealers

Outdoor wood sealers are easy to apply, and they will make your rough-cut lumber last much longer when used outside. These are commonly a combination of oils and chemicals that provide the wood with mildew and UV protection. The main goal of using a wood sealer is to keep the wood dry, which will prolong its lifespan and make it more durable. It’s best to use wood sealers on rough-cut lumber you will use for decks, fences, wooden exteriors, or gazebos.

2. Exterior Paint

Another easy way to treat rough-cut wood for outdoor use is to apply exterior paint onto the wood. Just choose a water-resistant paint and paint over the lumber. Using exterior paint might not be an option for people who still want to preserve the wooden look, though. It works best for outdoor furniture, but you can use it for other outdoor wood projects too.

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3. Wood Oils

If you’re looking for an easy solution to treating rough-cut lumber, think about using wood oils. It’s a natural way to protect the wood and prevent decay and rotting. It will provide you with a natural look once you finish, and it will be weather resistant. Although this is a good option, it might not be enough for outdoor usage, so it’s best to mix this method with wood sealers for the best results. If you just use wood oils, the wood will need regular maintenance to keep everything in shape.

4. Epoxy

If you’re looking for the best option to protect rough-cut lumber from water damage, choose epoxy. It’s a polymer that is exceptionally resistant to any liquids. When you apply epoxy to rough-cut lumber you can be sure it’s water-resistant, and therefore it will have a longer lifespan. We recommend using a layer of wood oils and then the epoxy, since epoxy is not UV resistant. The only downside to using epoxy is that once you apply it to the wood, you should wait several days or longer for everything to set completely.

Which wood is the best for outdoor use?

Depending on what kind of project you have in mind, you can use various types of wood outdoor. Both softwoods and hardwoods can be used outside, although hardwoods are more durable. These are our wood recommendations for outdoor usage:

  • Cedar
  • Pine
  • Teak
  • Redwood
  • Cypress
  • Oak
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Of course, there are plenty of other options depending on what you want to achieve. Make sure to familiarize yourself with all wood options and know their pros and cons before you make a purchase.

How long will rough-cut lumber last outside?

Rough-cut lumber is very weather-resistant, and it will have a shorter lifespan than commercial wood. Still, rough-cut lumber can last anywhere from 5 to 50 years outside, depending on the conditions. You can always treat the wood by using some of the methods we mentioned to prolong its lifespan. When rough-cut lumber is treated, you can expect it to last at least twice more as usual.

How To Treat Rough Cut Lumber For Outdoor Use (4 Easy Steps) | House Grail (4)

How do you keep your rough-cut lumber from rotting?

To stop rough-cut lumber from rotting, you need to treat it properly. The treatment needs to be UV and water-resistant, and anything from wood vanishes, sealers, oils, or epoxy will work just fine.

Can you use rough-cut lumber to build a deck?

You can use rough-cut lumber to build a deck without any issues. As mentioned throughout the article, you should treat it first. That’s not a must, but if you want your deck to last, you shouldn’t skip that part. Rough-cut wood should always be treated to get the best out of it and increase its durability. Depending on what you want to achieve in the end, you can go for several different treatment options.

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Is rough-cut lumber expensive?

Rough-cut wood is affordable, which is why many people use it for their outdoor projects. You will have to treat it, but the final price will be lower than buying commercial wood, even with those costs. So, if you haven’t tried using rough-cut lumber for your outdoor projects, it might be an excellent time to begin and save some money.

How To Treat Rough Cut Lumber For Outdoor Use (4 Easy Steps) | House Grail (5)


Rough-cut lumber is a great, inexpensive option for outdoor projects. It has to be treated for outdoor use, but once you read this article, you should have no issues with treating it properly. So, take your time, finish the treatment process, and enjoy your new project while spending far less money on materials.

Featured Image Credit: JueWorn, Shutterstock


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  • 1 Before you begin
    • 1.1 1. Sand the wood
    • 1.2 2. Clean it up
    • 1.3 3. Stain the wood
    • 1.4 4. Apply wood varnish
  • 2 Other Methods of Treating Rough Cut Lumber for Outdoor Use
    • 2.1 1. Outdoor Wood Sealers
    • 2.2 2. Exterior Paint
    • 2.3 3. Wood Oils
    • 2.4 4. Epoxy
  • 3 Which wood is the best for outdoor use?
  • 4 How long will rough-cut lumber last outside?
  • 5 How do you keep your rough-cut lumber from rotting?
  • 6 Can you use rough-cut lumber to build a deck?
  • 7 Is rough-cut lumber expensive?
  • 8 Conclusion


How do you keep rough cut lumber from rotting? ›

You simply soak the lumber in the borate solution. Most people just build a trough using 6-mil plastic sheeting. The different borate chemicals come with instructions telling you how to mix the powder with water and how long to soak the lumber.

Does rough cut lumber need to be treated? ›

Rough lumber is untreated. It is stronger than treated lumber but it also absorbs more moisture. Rough lumber skips a step in the process. Some woodworkers prefer untreated lumber because they want to treat it themselves.

How do you treat rough cut pine for outdoor use? ›

Use an outdoor-rated finish like polyurethane, epoxy, lacquer, or varnish. Make a natural oil finish with one part tung or linseed oil, one part mineral spirits, and one part polyurethane. Use a stain sealant combo that gives your wood some color and a durable finish all in one.

Which wood preservative is best? ›

Product Guide: The Best Wood Preservers Compared
  • Wood preserver being applied.
  • Preserved and painted shed.
  • Ronseal Multi-Purpose Wood Treatment.
  • Cuprinol Wood Preserver Clear.
  • Ronseal Total Clear Wood Preserver.
  • Barrettine Premier Universal Preserver.
  • Barrettine Premier Wood Preserver.
  • Osmo End Grain Sealing Wax.
Sep 26, 2022

What's the best way to treat untreated wood? ›

To treat untreated wood for outdoor use, you need to apply the treatment. This treatment contains chemicals that can make the wood shrug off insects and harsh weather. The best option you have to treat wood for outdoor use is pine tar. It's a popular option as it can provide a stain-like finish.

What is the first thing to do with rough sawn lumber? ›

Use Milling Services

If this is first time working with wood, then it's smart to use an expert when it comes to the milling process. Milling is how you turn rough sawn lumber into usable wood. Do some research to find a professional near you who can assist with the milling process.

How long does fresh cut lumber need to dry before building a house? ›

Depending on the species and your climate, it can take from 2 to 12 months to bring 4/4 lumber from green to air-dry (12- to 20-percent moisture content, depending on your location).

What is the best sealer for untreated wood? ›

According to them, these are the nine most effective wood sealers:
  • Thompson's Water Seal. ...
  • Rainguard Premium Wood Sealer. ...
  • DEFY Crystal Clear Sealer. ...
  • Anchorseal 2. ...
  • Roxil Wood Protection Cream. ...
  • Eco-Advance Exterior Wood Waterproofer. ...
  • Ready Seal Stain and Sealer for Wood. ...
  • Pure Tung Oil Natural Wood Sealer.

How long will rough cut pine last outdoors? ›

So long as it's not in ground contact and you stain/paint the wood, it should last indefinitely. You want to make sure any exposed end grain is very well covered. The stain/paint protests the wood from water and UV exposure. Without a coating exposed wood will degrade pretty fast.

What is the best outdoor finish for untreated pine? ›

Polyurethane, paint, or epoxy finishes all work well for preserving pine objects and giving them a bright, clean finish. Once you've applied the right finish, your pine will be protected and able to withstand regular use outside.

What are the first 4 stages of wood preparation? ›

How Timber Gets From the Forest to Your Builders Merchant
  • Stage One: Felling. The first stage of preparing the timber for commercial use is called 'felling' – the process of downing individual trees. ...
  • Stage Two: Storing/ Transporting. ...
  • Stage Three: On Site. ...
  • Stage Four: Seasoning. ...
  • Stage Five: Preparing for Market. ...
  • Questions?
Aug 27, 2015

Can you use rough cut lumber to build a house? ›

Ungraded, unstamped lumber may be used for the construction of a house or accessory building on the owner's land if: 1. The timber is cut from the owner's land.

How long does it take for rough sawn lumber to dry? ›

Depending on outside conditions and lumber species and size, air-drying to a desired MC can take from several months to almost a year. Wood stored outdoors and under cover will dry to an approximate moisture content of 12 to 14 percent in western Oregon and 8 to 10 percent in eastern Oregon.

What is the best exterior wood preservative clear? ›

Sikagard Wood Preserver (clear): The best wood preserver for problem wood outdoors. This clear, water-based, microporous wood preserver gets right into timber to protect it from algae, moss, fungi, wood-boring insects and so on.

What type of preservative should be used on wood that will be outdoors? ›

The most common varieties of oil-borne preservatives include creosote and pentachlorophenol. Creosote have been historically used as a treatment for outdoor wood structures to prevent rot – such as railroad ties and bridgework.

Can I use untreated lumber outside? ›

Untreated Wood

Left in their natural, unfinished state, most woods deteriorate quickly when exposed to outdoor environments. However, there are several species that have naturally occurring chemicals that help them shrug off harsh weather and insects.

What is the best natural treatment for wood? ›

Natural Oil Wood Finishes. Linseed, tung, refined hemp, soy, and walnut oil are all-natural oils that on their own can be used to seal and protect wood. They are called drying oils. Drying oils penetrate, harden and preserve wood – providing a long-lasting finish that does not turn rancid.

How do you treat lumber naturally? ›

Linseed Oil

The oil pressed from flax has also been used for centuries as a natural wood preservative because of its ability to penetrate deep into porous fibers, and protect wood from moisture and rot.

What do you spray on rough cut lumber? ›

You can use water-based or oil-based paint, but water-based won't last as long on furniture or anything that comes into contact with water. The writers at Sawshub prefer oil-based paint because it holds up better to daily wear and tear. For the most even appearance, apply it with a paint sprayer.

What happens to rough lumber once it dries? ›

Stresses develop in lumber as moisture is lost during drying. Shrinkage in width and thickness will occur; warp, checks or other defects may develop. The potential for drying defects such as checking and warping also increases with greater lumber thickness.

What is the disadvantage of sawn lumber? ›

Despite the attractive look on the surface, there are certain drawbacks to plain sawn lumber. As the wood dries and ages, the tension of the tangential grain can make plain sawn planks cup, twist and sometimes bow. They also tend to absorb more moisture from the air which can also lead to unwanted movement.

How do you protect fresh cut lumber? ›

Seal the ends of the lumber.

The ends of lumber cure faster than the rest of the wood. To ensure that your wood cures evenly, it is best to seal the ends immediately after sawing the logs into lumber. You may coat each end of the wood in a commercial end sealer, paraffin wax, polyurethane shellac, or latex paint.

How do you store fresh cut lumber outside? ›

However, there is no issue with storing green lumber outside. If going this route, use stickers between each course of lumber to help it dry. Some woodworkers make a lean to for storing lumber outside. A lean to will help keep rain and/or snow off the lumber which will increase the drying rate.

What can I use to weather wood? ›

Use tools and other objects to distress wood. Try hitting it with a hammer, mallet, or metal chain to create small divots. A wood gouge may be helpful to add a few nicks here and there. You can also press the side of a large screw into the wood or hammer the side of an awl to create a long scratch.

What do you put on bare wood to seal it? ›

There are three types of clear topcoats used to seal natural wood or bleached furniture – polyurethane, polycrylic, and wax finishes. Each type of clear coat has different pros, cons, and projects that it's best suited for. Polyurethane is available in oil-based and water-based finishes.

Does Thompson's water seal protect untreated wood? ›

Applying Water Seal will not damage wood, but the level of waterproofing protection will vary depending on the type of wood being treated. For best results, we would recommend a dedicated preserver to protect exterior timber from rot.

What is the quickest wood sealer? ›

If drying time is important, shellac and lacquer finishes dry the fastest followed by water-based finishes. Varnish and oil take longer to dry, usually overnight in a warm room. Since lacquer dries the fastest, it works great when applied by a spray gun.

How do you keep pine from rotting? ›

So here are three tips to prevent wood rot from eating through your timber decks.
  1. Keep moisture out. The number one culprit in wood rot is moisture. ...
  2. Kill the fungi. Another way to prevent wood rot is to eliminate the fungi that eat through the timber. ...
  3. Use treated wood.
Aug 9, 2021

Should you paint or stain rough cut lumber? ›

Paint will last longer on smooth, edge-grained surfaces. Penetrating stains or preservative treatments are preferred for rough sawn lumber. These treatments often accentuate the natural or rustic look of rough sawn lumber and allow the wood grain and surface texture to show through the finish.

What does borax do to wood? ›

20 Mule Team Borax Products

This cost-efficient zinc borate protects wood and wood composites from destroying organisms, rot, decay, fungi, and subterranean termites. This high-performance industrial borate wood preservative is design to provide the highest concentration of boron with maximum solubility.

How do you seal raw pine wood? ›

Pine accepts clear finishes like varnish or polyurethane much like any other wood. Read the label on the can and apply according to the directions. First, however, seal any knots in the wood with a coat of clear shellac; this will keep pigments in the knots from bleeding into the finish.

What is the most durable exterior wood finish? ›

An epoxy sealer with an exterior varnish topcoat is the most durable outdoor finish and can last for many, many years. However, the initial application does take longer than exterior varnish.

Will treated pine last outside? ›

It is suitable for outside, above-ground use only. H4 Treated Pine provides additional protection to H3, protecting against severe decay that can occur when timber is in contact with water, such as for your decking posts that are in contact with the ground.

Can you stop wood rot once it starts? ›

Boric acid (borate) is one of the most effective fungicides for use in treating wood rot. It can be applied to wood during construction to prevent future rot, or as a treatment to stop an active decay fungus from growing.

Can you build with fresh cut lumber? ›

Building with green lumber for timber frame construction can save time, money and energy. With green timber, you can begin building right away without having to wait for the wood to dry, or having the added cost for kiln drying, which uses environmentally damaging fossil fuels during the drying process.

Does vinegar stop wood rot? ›

Vinegar can stop fungal spores from spreading, allowing you to contain the wood rot and stop it from causing further damage, but it's not the only treatment that can or needs to be applied.

What is the best exterior wood filler for rotted wood? ›

Best Wood Filler for Outdoor Use—Minwax Wood Filler

The Minwax stainable wood filler is great for outdoor use as it is weather and water-resistant, as well as rot-resistant. This two-part wood filler can be used to repair cracks and holes in wood and also to repair rotten wood.

Does borax stop wood rot? ›

Simply put borates or borax are naturally-occurring water-soluable salt-like acids. They are about as toxic as table salt to humans and pets but kill wood-consuming insects like termites, powder-post beetles, and old house borers. More importantly, it kills the wood destroying microorganisms that cause rot.

How long does fresh cut lumber need to dry before building with it? ›

Depending on outside conditions and lumber species and size, air-drying to a desired MC can take from several months to almost a year. Wood stored outdoors and under cover will dry to an approximate moisture content of 12 to 14 percent in western Oregon and 8 to 10 percent in eastern Oregon.

How do you season wood quickly? ›

6 Tips to Season Firewood Quickly
  1. Know the What Type of Wood You're Using. The type of wood you use matters. ...
  2. Prepare During the Right Time of Year. ...
  3. Cut, Split, & Size Your Wood Correctly. ...
  4. Keep It Outdoors. ...
  5. Correctly Stack the Wood. ...
  6. Properly Cover Your Firewood.

Will rough cut lumber last outside? ›

So long as it's not in ground contact and you stain/paint the wood, it should last indefinitely. You want to make sure any exposed end grain is very well covered. The stain/paint protests the wood from water and UV exposure.

What should lumber for construction be dried to? ›

A Note About Construction Lumber

Framing lumber is usually only kiln dried to 14 or 16 percent moisture, so significant shrinking and cracking is still to come. It's best to take this wood and bring it into your shop for a week or longer so the wood can achieve a MC appropriate for furniture.

How long before you can paint rough cut lumber? ›

Wash the rough cut lumber with the spray from a pressure washer nozzle held at least 12 inches from its surface. Allow the wood to dry for 48 hours.


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