What is the dressed size of a 2 x 4 timber?

The dressed size of a 2 x 4 timber is indeed 1.5 x 3.5 inches. This sizing reflects the dimensions after the wood has been planed and smoothed during the milling process, which reduces the nominal size. Originally, the timber is called a "2 x 4" because that is its intended dimension before any finishing work is done. However, when the lumber is dressed, it is trimmed to provide a smoother surface and consistent dimensions, resulting in the final size of 1.5 inches by 3.5 inches. Understanding this distinction is essential for anyone involved in construction or woodworking, as using the correct measurements is critical for ensuring the proper fit and stability in building projects.