How To Choose Lumber

Buy the right lumber for your DIY building projects

Selecting which type of lumber you use for a project depends on its ultimate purpose. For structural needs such as joists or beams, the look of the lumber isn’t a top priority. But if the lumber is going to be visible, you may want a higher grade of lumber. This guide will help you understand the measurements you need for your project, as well as steer you in the right direction when making lumber choices.

What Type of Lumber Do I Need?

Most decking and framing lumber comes in standard sizes, so once you have calculated how much you need, determine what type of wood is best for your project.  

Type of Lumber - To Choose Lumber

• Pressure treated lumber: Ideal for outdoor projects as it withstands the elements.
• Cedar: If treated regularly with preservative, it will resist rotting and be more aesthetically pleasing for outdoor projects than pressure treated wood.
• Redwood: Can be used for outdoor projects as it naturally resists rot and is more attractive than pressure treated wood.

Deciphering Lumber Measurements

Lumber is identified by its nominal size, which is its rough dimension before it is trimmed to finished size at the lumber mill. Actual sizes are approximate lumber dimensions after trimming.  


1 × 4


1 × 6


2 × 2

1½" × 1½"

2 × 4

1½" × 3½"

2 × 6

1½" × 5½"

2 × 8

1½" × 7¼"

2 × 10

1½" × 9¼"

4 × 4

3½" × 3½"