If you're planning an outdoor project like a deck or fence, you've likely come across pressure-treated lumber as a recommended material. But what is pressure-treated lumber, and how does it differ from regular wood? Let’s break it down.
How is pressure-treated lumber different from regular wood?
At first glance, pressure-treated lumber may look like regular wood, but there’s a major difference—its durability. Unlike untreated lumber, treated wood is infused with preservatives that help protect against rot, decay, and insects, making it ideal for outdoor use.
Want a visual guide? Check out our video explaining what pressure-treated lumber is!
How is wood pressure-treated?
Pressure treating is a process that forces preservative solutions deep into the wood fibers to enhance durability. This is done in an airtight cylinder using a vacuum and high pressure. Here’s how the process works:
- Loading the Wood – Lumber is placed inside a sealed pressure treatment cylinder.
- Vacuum Process – Air is removed from the wood to open up the fibers.
- Applying Pressure – A preservative solution is added to the cylinder under high pressure, penetrating deep into the wood.
- Quality Control – Technicians test the treated lumber to ensure it meets proper absorption levels for protection.
Types of pressure-treated wood preservatives
There are different types of preservatives used to pressure treat lumber. At ProWood, we primarily use MCA (Micronized Copper Azole)—a copper-based preservative that effectively protects against decay and insects while being environmentally friendly.
Other commonly used preservatives include:
Ecolife (EL2) – A non-metallic treatment with added water repellency.
ACQ (Alkaline Copper Quaternary) – A durable, widely used copper-based preservative.
How to identify pressure-treated lumber
If you're shopping at a home improvement store, here’s how to tell treated wood apart from regular lumber:
- Color – Pressure-treated wood often has a slight greenish tint due to the preservative treatment.
- End Tag – The best way to confirm if wood is treated is by checking the end tag, which details the preservative used and the treatment level.
Understanding pressure-treated lumber treatment levels
When selecting pressure-treated wood, it's important to choose the right treatment level for your project. ProWood has four different treatment levels based on AWPA standards that each have different applications. The two levels you’ll most commonly encounter in a store and online are Ground Contact and Above Ground. Here is what you need to know about them:
1. Ground Contact Treated Lumber
- Best for: Structural components, posts, joists, and beams.
- Contains more preservatives to withstand direct contact with soil and harsh conditions.
- More durable and long-lasting.
2. Above Ground Treated Lumber
- Best for: Railings, balusters, trim, and decorative elements.
- Contains a lighter preservative concentration.
- Suitable for areas with good drainage and airflow.
Why choose pressure-treated lumber?
Using treated wood for your outdoor projects offers several benefits:
- Rot & Pest Resistance – Prevents mold, decay, and insect damage.
- Long-Lasting Durability – Can last decades with proper maintenance.
- Safe & Environmentally Friendly – Modern treatments are safe for you, your pets, and the environment.
- Natural Wood Aesthetic – Maintains the beauty of real wood while enhancing its lifespan.
Where to buy pressure-treated lumber
Looking for high-quality pressure-treated lumber? Find a local ProWood dealer near you!