What Are Lumber Grades?

Lumber grading is a standardized system used to classify wood based on its quality, appearance, and structural properties. Understanding these grades helps you choose the right lumber for your project while staying within budget.

Softwood Lumber Grades

Softwood lumber (like Douglas Fir, Western Red Cedar, and Alaska Yellow Cedar) is typically graded into several categories:

Structural Grades

• Select Structural: The highest structural grade with excellent strength and appearance
• No. 1 & Better: High-quality lumber suitable for exposed structural applications
• No. 2: Most common structural grade, good strength with some defects allowed
• No. 3: Lower structural grade, suitable for non-critical applications

Appearance Grades

• Clear (A & Better): Highest appearance grade with minimal defects
• C Select: Good appearance with small, tight knots allowed
• D Select: Some defects allowed but still suitable for painting

Common Grades

• No. 1 Common: Good for general construction, some knots and defects
• No. 2 Common: Standard construction grade with more defects allowed
• No. 3 Common: Utility grade lumber with significant defects

What to Look For

When examining lumber grades, inspectors look for:

• Knots: Size, location, and tightness of knots
• Grain: Slope and direction of wood grain
• Defects: Splits, checks, and other imperfections
• Moisture Content: Seasoning quality and dryness
• Wane: Missing wood along edges

Choosing the Right Grade for Your Project

For Structural Applications:

• Floor joists, rafters: No. 2 & Better or Select Structural
• Load-bearing beams: Select Structural or No. 1 & Better
• General framing: No. 2 grade is typically sufficient

For Appearance Applications:

• Fine furniture: Clear grades or FAS (First and Seconds)
• Trim and molding: C Select or better
• Painted surfaces: D Select is often adequate
• Rustic projects: No. 1 or No. 2 Common can add character

For Budget-Conscious Projects:

• Utility projects: No. 3 Common or utility grade
• Hidden framing: Construction grade lumber
• Temporary structures: Lower grades can be cost-effective

Special Lumber Designations

Kiln Dried (KD)

Lumber dried in a kiln to specific moisture content, typically 19% or less. This reduces shrinkage and warping after installation.

Surfaced (S4S, S1S2E)

• S4S: Surfaced on all four sides
• S1S2E: Surfaced one side, two edges
• Rough: Not surfaced, full dimensional size

Pressure Treated

Lumber treated with preservatives for outdoor use and ground contact applications.

Understanding Lumber Sizes

Remember that lumber dimensions are nominal, not actual:

• 2x4: Actually 1.5" x 3.5"
• 2x6: Actually 1.5" x 5.5"
• 2x8: Actually 1.5" x 7.25"
• 1x6: Actually 0.75" x 5.5"

Tips for Buying Lumber

1. Know your project requirements: Structural vs. appearance needs
2. Inspect before buying: Look for defects that matter to your project
3. Consider moisture content: KD lumber is worth the extra cost for many projects
4. Buy extra: Account for waste and mistakes
5. Store properly: Keep lumber flat, dry, and well-supported

Our Overstock Lumber Advantage

At West Wind Forest Products, our overstock lumber often includes higher grades at lower prices. You might find Select Structural lumber at No. 2 prices, or Clear grade lumber at common grade costs. This makes it possible to upgrade your project quality while staying within budget.