Pressure Treated Wood: Types, Grading Standards & More

Understanding Pressure Treated Wood for Your Deck

Pressure treated wood is one of the most common materials used in deck building—and for good reason. It’s durable, affordable, and resistant to insects and rot. But not all pressure treated lumber is created equal. Here’s what you need to know when selecting the right type and grade for your deck project.

Types of Pressure Treated Wood

There are several categories of pressure treated wood based on treatment and intended use:

✔🔸 Above Ground: Best for parts of the deck not in contact with soil or moisture, like railings or framing.

✔🔸 Ground Contact: Treated for higher resistance to moisture and decay, ideal for posts or joists near or in the ground.

✔🔸 Marine Grade or Heavy-Duty: Used for extreme moisture environments—over water or in constantly wet areas.

How It’s Treated

The treatment process forces preservatives deep into the wood to protect against fungi, termites, and moisture damage. Common preservatives include:

✔🔸 Alkaline Copper Quaternary (ACQ)

✔🔸 Copper Azole (CA)

✔🔸 Micronized Copper (MC)

Always look for the tag or stamp to confirm the type of chemical used and the treatment level.

Grading Standards Explained

Grading refers to the wood’s appearance and structural quality:

✔🔸 Select or Premium Grade: Minimal knots and defects—great for visible areas like decking boards.

✔🔸 #1 Grade: Fewer and smaller knots, higher strength.

✔🔸 #2 Grade: More knots and blemishes—often used for framing or hidden structural parts.

✔🔸 Construction or Standard Grade: Budget-friendly but lower appearance quality.

How to Choose the Right Type for Your Project

✔🔸 Deck Framing: Use ground-contact grade for posts and joists near the soil.

✔🔸 Decking Surface: Go for select or #1 grade boards for a smooth, polished look.

✔🔸 Railings & Steps: Choose boards with fewer knots and a cleaner grain pattern for aesthetics and safety.

Tips for Working with Pressure Treated Wood

✔🔸 Let it Dry: PT wood is often damp; allow it to dry before painting or staining.

✔🔸 Seal It Properly: Use a water-repellent finish to protect and extend its life.

✔🔸 Use Appropriate Fasteners: Stainless steel or hot-dipped galvanized nails and screws prevent corrosion.

Build Strong, Build Smart

Choosing the right pressure treated wood is foundational to a durable and safe deck. Understanding the differences in type and grade ensures your deck not only looks great but lasts for years.

Get Expert Advice for Your Deck Project

Need help choosing the best materials? North Georgia Elite Decks can guide you every step of the way—from design to build. Contact us today for expert consultation and a free estimate on your next project!