Are Fence Posts Typically Pressure Treated?

Pressure treating wood extends its life and protects against rot and damage by moisture, insects, or other organisms. So, you might wonder if fence posts are pressure treated in general. We researched on your behalf to bring you the following answers.

Yes, fence posts are typically pressure treated due to the following:

  • It prevents rot due to exposure to moisture.
  • It increases resistance to damage by insects.
  • Pressure-treated fence posts are retardant to fire.

Keep reading to understand why fence posts are typically pressure-treated wood, how long they last, and what is the best wood for this type of treatment. Could there be a downside to this treatment? You’ll find out more as you read on. 

New fence under construction, Are Fence Posts Typically Pressure Treated?

Reasons Why Fence Posts Are Typically Pressure Treated

Generally, wood is prone to decay, reducing its lifespan. But treating it preserves it to last longer. Using pressure-treated timber for your fence thus prevents quick deterioration.

Pressure-treated pine is a popular choice for fence posts. This is because it is easy to work with, and its cell structure easily absorbs the chemicals during the pressure-treatment process.  

As a homeowner, you most likely would prefer a fence that is affordable and durable, and that would mean using pressure-treated softwood because of these reasons below:

Wooden garden fence coated with medium oak colour paint

It Prevents Rot Due To Exposure To Moisture

Hardwoods would be the most suitable choice for fence posts due to their natural resistance to moisture. However, these woods are more difficult to work with and are expensive. The solution is to use the less expensive, more versatile softwood that is pressure treated by infusing chemicals into them to protect against moisture.  

A huge field with trees surrounded by a fence

It Increases Resistance To Damage By Insects

Insects love wood, with termites being number one on the list because they eat and digest wood. Other insects that can cause damage but do not eat the timber include wood-boring beetles and carpenter ants that create holes in the wood. 

The chemicals in pressure treatment resist the insects from attacking the wood. 

Pressure-Treated Fence Posts Are Retardant To Fire

Wood is easily combustible. That means wood used in construction can easily catch fire, including your wooden fence. 

Pressure-treated wood is a method that adds preservatives and fire retardant solutions deep into the wood by using pressure. This method effectively treats the wood and makes it great for fence posts as they last longer.

Fire-retardant chemicals infused deep into the wood during pressure treatment change the composition of the wood. If the wood catches fire, it produces carbon dioxide and water, slowing down or halting the flames from spreading. 

Do Pressure Treated Wood Rot?

Rotting timber retaining wall

Natural wood lasts about a year or two before it starts to rot. That is why pressure treating wood is worthwhile because your wood resists rotting much better and lasts longer.

However, your pressure-treated fence post is not exempted from rot because preservatives in the wood do not last forever. Here are reasons why your pressure-treated wood will rot:

Fungi Attack

After a while, the chemicals in the pressure-treated wood would diminish, lowering resistance to water and insects. With time, wood will bend, crack or move, resulting in water finding its way into the wood.

If you do not tackle this situation immediately, the wood becomes a good breeding ground for fungi to grow, causing the wood to rot.

Water Damage

As seen above, any chance for water to seep into the wood will create a good ground for fungi to thrive on the wood.

And, since fungi are everywhere, they will multiply and cause the wood to decay if the problem is not solved early.

Chemical Reactions

Even though wood goes through a chemical reaction by pressure treating it, it can further go through more chemical reactions. 

For example, the screws or nails used on pressure-treated wood can cause a chemical reaction that results in rot, which is known as galvanic rot.  

How To Prevent Pressure-Treated Wood From Rotting

Barbed wire fence in the countryside

Now that you know what causes pressure-treated wood to rot, can it be prevented? Yes, follow these steps for rot prevention:

Use Sealers

Sealers provide an extra layer of protection against moisture and insects. There are many sealers including paint, sealants, oils, varnishes, and stains.

For fences, the best sealer is a water repellent like the Roxil protection cream below. You could also use a semi-transparent penetrating sealer because it does not crack or peel.

If you prefer to use paint, first coat the base with a sealer preservative or paintable water repellent and leave it to dry for two days under warm sunny weather. Afterward, you may start painting.

Start by applying an acrylic latex primer. Next, apply two topcoats of good quality acrylic-latex exterior house paint. If you want to repaint, scrape the loose paint and dirt off the wood.

Varnish and color stains are not suitable for fences because they cannot withstand UV rays.

Have a look at this product on Amazon.

Using Mildewcides

Mildewcides prevent the growth of fungus on wood. Whenever you want to apply a finish to your fence post, you can opt for one that contains mildewcide.

Application Of UV Stabilizers

You can prevent the effect of UV rays on fence posts by applying UV stabilizers. Look for finishes and coatings that contain UV stabilizers. 

Click here to view this product on Amazon.

Frequent Inspection

Inspecting the fence posts frequently will not stop the wood from rotting, but at least you will know early enough when rotting has started.

What To Expect From Pressure-Treated Fence Posts

We have seen the main advantages of using pressure-treated wood for fence posts. We have outlined here more benefits and disadvantages as well.


The advantages of pressure-treated wood include:


As seen earlier in the post, pressure-treated wood is easy to work with and versatile. For example, you can improve the aesthetics of your compound by staining the fence to match the color of your house.

Lasts Long

The chemicals in the pressure-treated wood resist moisture and insects that would cause it to decay. It is thus durable, lasting for decades. However, this does not mean you neglect to look after the wood and give it proper care.

Easy To Repair

The repairs needed on pressure-treated wood are easy and inexpensive. You don’t have to worry much if it is accidentally damaged.

Environmentally Friendly

Pine, which is commonly used for pressure-treated fence posts, blends well with nature because it is in itself a natural wood. It also grows fast, making it readily available for use.


Below are some disadvantages of pressure-treated wood:

Forming Splinters

Wood exposed to the elements will inevitably crack and splinter over time. The alternate cycles of wet and dry seasons will cause the wood to become drier, which can lead to splitting. Thus, it will necessitate occasional repairs, which can be done as soon as you spot the cracks or any other damage to prevent it from becoming worse.


Ultraviolet rays will cause the wood to fade with time. By using UV stabilizers, you can continue to maintain your favorite color.

Constant Maintenance

Your fence will need a yearly fresh coat of sealant to protect it, or blemishes and stains from leaves, debris, and other material will be visible.

Risk of Chemicals

Chemicals in the pressure-treated wood can cause hazards when not handled properly. If you cut, trim, or burn it, harmful toxins are likely to find their way into the environment around. That is why it should not be near food or water.

Also, when working with this wood, you need to wear safety gear to protect yourself. When you need to dispose of it, don’t throw it anywhere. Instead, take it to a recycling center that handles this type of wood.

How Long Will Pressure-Treated Fence Posts Last?

Wooden privacy fence in backyard with peeling paint and stain and green algae, mildew, and moss on boards

Pressure-treated fence posts can last up to 10 to 15 years without showing decay or rot. But it is dependent on the climate and the type of wood you use, as well as how well you maintain it. 

As shown earlier in this post, you can extend the life of your fence by applying sealers, mildewcides, and UV stabilizers immediately if you notice signs of damage to your wood. 

In Closing

Pressure-treated wood lasts long and is excellent for fence posts. However, it can rot and decay because the chemicals wear off over time. Thus, you need to protect your fence posts by applying sealers, mildewcides, or UV stabilizers, not forgetting to inspect them often.

The advantages of pressure-treated wood make it a great choice for fence posts. But it also has its downsides.

Before you go, check out these other posts:

Can A Neighbor Paint My Fence On Their Side?

Best Wood For A Picket Fence [5 Great Options!]