What is typically applied to the outside of studs to weatherproof a house?

Sheathing is the correct answer because it serves as a crucial layer of protection on the exterior of studs in a house. Typically made from materials like plywood or oriented strand board (OSB), sheathing provides structural support as well as a barrier against the elements, helping to insulate the house and prevent moisture infiltration. This contributes significantly to the overall weatherproofing of residential structures.

In contrast, drywall is generally applied to the interior walls for finishing and does not have weatherproofing properties. Insulation, while important for thermal efficiency, is usually placed between the studs rather than on the exterior, and it does not serve as a weather barrier in itself. Vinyl siding is an exterior finish that adds aesthetic value and some degree of weather resistance but is reliant on the underlying sheathing for effective protection. Thus, sheathing plays a fundamental role in safeguarding the structure against various weather conditions.