What is Pressure Treated Wood used For?

what is pressure treated wood used for

Pressure-treated wood is a marvel of modern construction. But what is treated wood used for? Is pressure-treated wood good for everything? These are the questions we answer in today’s discussion. 

Pressure-treated wood is used for outdoor construction, where the wood will come into contact with moisture. Sometimes, pressure-treated wood is used when contacting cement, as moisture wicks through concrete pores. 

Pressure-treated wood is useful material. However, if you don’t understand how to use it, you will become frustrated. In addition to this, the chemicals in pressure-treated wood can be a hazard. 

But don’t worry! In this article, we discuss how to use pressure-treated wood safely and how to avoid dangerous situations. 

When Should I Use Pressure Treated Wood? 

Pressure-treated wood should be used for most outdoor projects. It is designed to be much more resistant to the effects of rot and insects than non-treated wood. 

Here are several great projects for pressure-treated lumber: 

Let’s look at these ideas closer. 

Pressure-treated Wood for Decks 

When you take the time to build a nice deck, you don’t want to worry about it breaking down within a couple of years. Pressure-treated lumber offers good protection for a deck. 

Of course, you want to be mindful of the type of pressure-treated wood you use for your deck. There may be times where you use a stronger treated wood for the foundation and less potent treatment for the floor and rails. 

Also, for more protection from pressure-treated lumber, sealing your treated wood with a penetrating oil-based stain will inhibit harmful contact with chemicals. 

Pressure Treated Wood For Sheds 

Your shed often houses useful and expensive yard tools. If the integrity of your shed becomes compromised, you could damage your tools and toys.

Sheds are a good time to consider using pressure-treated wood. Sometimes, when building a semi-permanent shed, builders will use treated wood to build the shed’s foundation. 

While pressure won’t be as solid as concrete foundations (and should not be used for large permanent structures), it will resist rot and insects. 

Pressure Treated Wood for Docks and Posts 

Any time wood will be in contact with the earth, pressure-treated wood is a great idea. This is especially true for posts or foundational lumber that will be exposed to the elements. 

In some instances, you may not use treated wood for certain parts of a structure – like the railing on a deck. However, in these instances, it is still advised to use pressure-treated wood for the foundations. 

If you’re building a dock that will contact water, you definitely should use pressure-treated lumber. Otherwise, your wood will quickly rot away. 

Note: Pressure-treated lumber does protect against rot and insects; however, it does not protect against normal corrosion of lumber. Also, this type of wood can still easily warp after it dries and split during use. While treated lumber is incredibly useful, it’s important to understand its limitations. 

How is Pressure Treated Wood Made? 

Pressure-treated lumber is made, as its name implies, through pressure treatment. When treating wood, manufacturers will slide the lumber into a large chamber. The chamber closes and is then depressurized. Then, the treatment agent is introduced and is essentially pulled into the wood. 

This process allows the treatment to penetrate deep into the fibers of the wood. 

Types of Pressure Treated Wood

There are several types of pressure-treated wood. There is pressure-treated wood designed for extreme exposure to water, and there is treated wood made for indoor use. 

Also, you will see some pressure-treated plywood (useful for sheathing sheds), and pressure-treated fencing. 

Another category of pressure-treated wood is the actual chemicals uses to create the treatment. 

The chemical make-up of pressure-treated wood has changed over time for safety considerations. However, all types still exist in one form or another. 

In the past, it was very common for pressure-treated lumber to contain arsenic – now, this is rarely used. 

When Should I Avoid Using Pressure Treated Wood? 

While treated wood is useful, it is not without flaws. Remember, pressure-treated wood contains pesticides. At the same time, these chemicals are dangerous to bugs. Good. These same chemicals are also dangerous to humans. Bad. 

So here are several times you should avoid using pressure-treated lumber: 

  • Indoor use – when there is no worry about contact with serious moisture, there is no major need for pressure-treated lumber. The cost-benefit just isn’t there. However, like when building the initial part of a foundation, there are some times that pressure-treated wood will be used in the frame of a home. 
  • Children’s play equipment – you don’t want children or adults in direct contact with pressure-treated lumber. If you must use some pressure-treated wood for the foundation of a playset, be sure to thoroughly stain and seal the treated wood to reduce exposure. 
  • Garden beds – There are better alternatives for garden beds. Pressure-treated wood could leak chemicals into your soil, creating hazardous conditions. Cedar is naturally rot and insect resistant, is a better wood for this task. 

Alright, now let’s discuss 

Is Pressure Treated Wood Safe? 

Pressure-treated wood is only safe when used properly. If it is used improperly, it can cause harm. 

Here are several factors that make pressure treated wood potentially unsafe: 

  1. Chromated Copper Arsenic CCA 
  2. Alkaline Copper Quat ACQ
  3. Ash from pressure-treated wood
  4. Sawdust from pressure-treated wood

Let’s discuss these in more detail. 

Chromated Copper Arsenic in Pressure Treated Wood 

As you may notice, arsenic is not a pretty substance. That’s right, rat poison. Well, it turns out this was used almost exclusively in pressure-treated wood until people figured out it wasn’t very safe.

As a result, everyone made a big switch to using ACQ – alkaline copper quat and other non-arsenic-containing preservatives. 

Only a few types of pressure-treated wood still use arsenic; however, their manufacturing process and sale are regulated. Just beware that this stuff is still out there. While it does a good job of preventing rot and insect invasion, it can also be harmful to your family. 

Alkaline Copper Quat in Pressure Treated Wood 

This substance does not contain arsenic; however, it can still be problematic. While there is less chance of causing harm to your family, you still wouldn’t want to touch this stuff constantly.

Also, alkaline copper quat, or ACQ, is quite toxic to marine environments. As a result, take care when using this type of pressure-treated wood around ponds or streams. 

Furthermore, both CCA and ACQ can be extremely flammable. This is one of the reasons pressure-treated wood is not used extensively indoors. If you used treated lumber for all your framing, even a small fire could quickly get out of hand. 

Not to mention, the toxic ash and smoke from pressure-treated wood could be devastating in a fire. 

Ash from Pressure Treated Wood 

If you’re wondering, can I burn pressure-treated wood? The answer is no. You should never burn pressure-treated lumber. This lumber can create toxic ash and fumes. 

If you can’t burn pressure-treated wood, you may be wondering how you get rid of it. Well, here are a couple of ideas… 

First, contact your local waste management department and see if they have any information on disposing of pressure-treated lumber. Each area may have a slightly different procedure. If you are disposing of pressure-treated wood treated with arsenic, be especially cautious about handling it. 

Second, try to reuse whatever parts of the pressure-treated wood you can. It’s made to last. Unless the wood has eroded to the point of no return, you’ll likely be able to find a use for it. 

Sawdust from Pressure Treated Wood 

Is sawdust from treated wood safe? Not really. While it isn’t healthy to inhale any sawdust, you should especially avoid inhaling sawdust from pressure-treated wood. 

Here are some ways to stay safe with pressure-treated sawdust: 

  • Set up a vacuum system – setting up a workshop vacuum system to remove dust is well worth the cost. Especially if you’re working will some toxic materials, like treated wood. Of course, a vacuum system also keeps your work area clean and organized. 
  • Wear a mask – when you’re cutting through treated wood, you should always wear a mask and eye protection. Inhaling any particles will not be good for you. 
  • Cut in an open area – if you don’t have a workshop with a vacuum system, it’s best to make your cuts outside in a well-ventilated area. This will prevent concentrated exposure. 
  • Keep kids and pets away – make sure you keep in mind where your family members are when cutting pressure-treated lumber. 

Hopefully, these tips will help you stay safe the next time you use pressure-treated wood. 

Can I Use Pressure Treated Wood Around My Garden? 

It’s not recommended to use treated wood around gardens – especially if you are growing edible plants. 

Cedar is a better alternative for making garden boxes, etc. With no treatment, cedar is naturally water and insect-resistant. Cedar is so tough that some people will build their roofs with cedar shingles. 

If you simply must use pressure-treated lumber around a garden, use a moisture barrier to prevent chemicals from seeping into your rich soil. 

Final Words on Pressure Treated Wood 

Pressure-treated wood is used for outdoor applications when the wood will be near or in direct contact with water and moisture. Pressure-treated wood will resist rot and insects; however, it can still corrode over time. 

If you do not want to take any risks with the chemicals used in pressure-treated wood, then cedar and redwood are natural alternatives; however, they will be more expensive than treated lumber.