Nominal Size (Lumber)

Definition

Nominal size refers to the commercial size designation of width and depth in standard sawn lumber and glued-laminated lumber grades, which is larger than the actual net size of the finished, dressed lumber.

Purpose

The nominal size of lumber provides a standardized reference for purchasing and specifying lumber dimensions. It simplifies communication in the industry, despite the actual finished size being smaller due to the dressing process.

Examples of Use

• Building Construction: Using 2x4 nominal size lumber for framing walls, which actually measures 1.5 inches by 3.5 inches.
• Furniture Making: Specifying lumber dimensions for furniture parts based on nominal sizes.
• Decking: Using nominal size lumber to standardize measurements for decking materials.

Related Terms

• Actual Size: The true measured dimensions of lumber after it has been planed and finished.
• Dressed Lumber: Lumber that has been surfaced to smooth dimensions.
• Dimensional Lumber: Lumber that is cut to standardized width and depth specified by nominal sizes.

Notes

• Size Discrepancy: Be aware of the difference between nominal and actual sizes when planning and constructing.
• Standards: Nominal sizes are standardized, but actual sizes may vary slightly between manufacturers.