Studs must be a minimum of which standard or stud grade lumber?

The minimum requirement for studs in residential construction is typically No. 2 grade lumber. This standard is set because No. 2 grade lumber provides an adequate balance of strength, stability, and cost-effectiveness necessary for structural applications like framing walls. No. 2 grade allows for some knots and imperfections, which do not significantly compromise the structural integrity needed for studs.

Using lower-grade lumber, such as No. 3 or lower, could result in weaker structural performance, potential warping or cracking, and ultimately compromise the safety and durability of the construction. This requirement ensures that studs can adequately support loads, maintain straightness over time, and perform well under the stresses of a residential framework.