Which component contributes the least thickness to the exterior wall?

The component that contributes the least thickness to the exterior wall is drywall. Drywall, also known as gypsum board or wallboard, typically has a thickness of about 1/2 inch to 5/8 inch. It is primarily used as an interior finish to provide a smooth surface for painting or other wall treatments.

In contrast, the other components in the exterior wall assembly have greater thicknesses. For example, studs, which are structural framing members, generally have a thickness of about 2 inches. Sheathing, often made from plywood or oriented strand board (OSB), adds additional thickness, typically ranging from 1/4 inch to 1/2 inch or more, depending on the material used. The exterior finish, such as siding or brick veneer, also adds significant thickness to the wall assembly.

Understanding the proportions and functions of each component helps in evaluating the overall wall assembly and its performance, such as insulation, structural integrity, and aesthetic appeal.