Outdoor Woodworking Projects: Wood treatment

Wood is prone to rotting, softening, and color damage due to the outdoor elements. In this article, I will show you how to treat wood for outdoor use to prevent damage to your project.


3 Types of wood damage

The three main types of wood damage are sun damage, water damage, and bug infestation.

Sun damage

Wood sun damage normally consists of discoloration, fading, and weakening.

Water damage

Wood water damage can result discoloration, warping, mold and rotting, and weakening of the wood.

Bug infestation

Bug infestations like having wood-boring beetles can result in discoloration, visible holes, and weakening of the wood.

How to treat wood for outdoor use

When creating projects that will be in the outdoor elements, you will need to take extra steps to prevent wood rot and bug infestations.

5 steps to treating wood for outdoor use

  • Use Pressure Treated Lumber
  • Outdoor grade wood glue
  • Use outdoor grade hardware
  • Use exterior grade finish
  • Seal all sides

Below, I will explain the 5 ways to treat wood for outdoor use in more detail.

Use Pressure Treated Lumber

Pressure treated lumber are infused with preservative chemicals that protects the wood to natural elements such as sun exposure, rain, and insects.

Not using pressure treated lumber will greatly increase your chances of wood rot and bug infestations because rain or insects only need a small, unsealed, section to penetrate the wood.

Outdoor grade wood glue

You will wood glue that is recommended for outdoor use and is waterproof. Not using the correct wood glue will weaken the joint over time. Not only does this decrease the durability of the project, but you will also have an unsealed opening in the wood that can become infected.

If the project is covered under a patio, then water resistant wood glue will suffice. However, if the project is in direct elements, waterproof wood glue is essential.

Top water-resistant wood glue

  • Titebond PREMIUM – $5.48 (8fl/oz)
  • Gorilla Wood Glue – $4.98 (8fl/oz)

Top waterproof wood glue

  • Titebond ULTIMATE – $7.48 (8fl/oz)
  • Gorilla Wood Glue Ultimate – $7.98 (8fl/oz)

To learn more about wood glue, use, assembly, and strength, then check out my article “Wood glue: Strength, removal, and how to”.

Use outdoor grade hardware

Any screws, braces, or hardware that is used will need to be recommended for outdoor use if your project is in the direct elements.

If your project is constantly covered, like under a patio, and is exposed to indirect elements, then you can skip this part.

Not using screws that are treated for outdoor use will rust over time and affect the strength of the joints.

Exterior or deck screws will have enough protection for the outside elements.

Use exterior grade finish

You will also need a waterproof finish and sealer. Some paint is stain and sealer all in one. If it is not all in one stain and sealer, then you will need a waterproof sealer to further protect the wood.

Seal all sides

One of the next most important steps aside from using pressure treated lumber, is sealing all sides of the wood with the exterior grade finish and sealer.

This is essential, because it will not matter if you use waterproof sealer, wood glue, and hardware if you only paint one side of the wood.

You will need to seal all areas where water can seep through or where bugs can enter.

Read on

So far, you have learned about different types of wood damage and how to prepare your project for outdoor use.
Next, we will discuss how to look for signs of wood rot, how to treat wood rot, how to look for sign of bug infestation and treat infested wood.

How to check for wood rot

Rotting wood is not as durable as regular wood and it can spread very easily. Wood can be rotten beyond repair and is why it is important to catch wood rot early.

These are the 4 things to look for when checking wood for rot.

Soft spots

Soft spots and wet spots are an indication of wood rot. This section of the wood will be soft to the touch and may feel wet or spongy.

Brittle wood

Chipping, flaking, and brittle wood is another sign of wood rot and is often accompanied by soft spots in the wood.


Discoloration and dark spots are more commonly seen in wet rot and later stages of dry rot. Discoloration can look like white spots, dark spots, and yellow or pigmented spots in the wood.

Visible fungus

Visible fungus is a tale tale sign of wood fungus and rotting. Fungus normally appears in later stages of wood rot.

How to fix wood rot

There are two main types of wood rot, dry rot and wet rot. Wet rot is much easier to treat and quicker to notice than dry rot.

Wet rot

  1. Dig out rotten wood
    • First you will need to remove the soft wood with a chisel.
    • It is essential to remove all of the rotten wood before moving to the next steps. Sanding some of the solid wood to ensure you remove all of the soft wood is a good practice.
  2. Spray fungicide
    • Next you will spray fungicide or some form of wood treatment to protect the wood from further rotting.
    • This step is important to prevent the wood rot from spreading even after you removed all visible signs of rot
  3. Use wood filler
    • Now you will want to fill in the area where the wood rot was. This will bring some of the sturdiness of the wood back and look.
  4. Seal wood
    • After applying the fungicide and wood filler, you will want to properly seal all sides of the wood with sealer that is recommended for outdoor use.
    • This will prevent the wood from rotting over again.

Once you notice dry rot, it is likely more advanced and more difficult to treat. If the rot has spread to multiple pieces of lumber and/or has rotted through the wood. You will likely need to replace the wood that is infected or call professionals.

Signs of bug infestation in wood

It is fairly common have untreated wood laying around a garage that becomes home to insects such as worms, boring beetles, and spiders.

Some signs of bug infestations in wood are visible holes, tiny dark spots, bug droppings, and raised wood grain or finish.

Visible holes

Visible holes are signs that inspects have entered or exited the wood.

Bug holes are normally circular and may be seen in a pattern or cluster in the wood. These holes should not be confused with wood knots that are natural imperfections in the wood.

Tiny dark spots

Tiny dark spots can be a sign of a fungal infection, beg bug blood, wood boring beetles, and other small inscects.

Bed bug blood and mold commonly look very similar. You will see ink-like stains like someone took an ink pen and left it on the wood for a couple of minutes.

Wood boring beetle and other insect marks look more like defined black pen spots.

Insect droppings and eggs

Insect droppings and eggs are a definet sign that a bug or rodent has been there. Droppings may not be a sign of a larger infection, but if not treated can lead to one.

Depending on the droppings and eggs, you can determine if it’s from roaches, rats, ants, beetles, and other insects.

Raised wood grain or finish

Damaged wood

Wood powder

Some insects leave behind wood powder. Fresh powder is a sign of an active infection while old powder can indicate that the insects have left the wood.


In this article, we went over how to choose wood for outdoor use, types of wood damage to look for, and ways to fix damaged wood.

Thank you so much for taking the time to read this article and I wish you luck on your woodworking journeys!


My name is Rachel Blanding and I am a woodworker. I started woodworking at the beginning of the COVID-19 pandemic. I mainly create and refurbish furniture and create art. In this site I will share with you the knowledge I have gained over the years, and what worked for me and what didn't.

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