What is the actual size of 2×12 lumber?
The Correct Answer and Explanation is :
The actual size of 2×12 lumber is 1.5 inches by 11.25 inches. This size is the result of the standard milling process, where the dimensions of the wood are reduced from their nominal size.
Explanation:
The dimensions of lumber are referred to by their “nominal” size, which is the size the wood is labeled with when it is purchased. For example, a piece of lumber labeled as “2×12” is the nominal size. However, due to the drying and planing processes that occur after the wood is cut from the tree, the actual dimensions of the wood are smaller.
When wood is initially cut from logs, it is typically rough and oversized. Over time, it is dried (usually in a kiln), and the surface is smoothed (or “planed”) to make it more uniform and easier to work with. This results in the wood losing some of its original thickness and width.
For a “2×12” piece of lumber:
- Nominal Width: 2 inches (as stated) is actually 1.5 inches after the milling process.
- Nominal Length: 12 inches is the nominal length, but the length will typically be measured in the full length of the board, which is often sold in increments like 8, 10, or 12 feet.
- Nominal Thickness: A 2×12 starts as a piece that is about 2 inches thick before drying and milling, but after the process, it measures 1.5 inches.
This reduction in size occurs because the initial rough lumber is larger than the finished product. The milling process involves smoothing the surface and eliminating irregularities, which is why the “actual” size is smaller than the nominal size. This naming convention has been in place for a long time, even though the actual dimensions have been standardized at smaller sizes.