Where must double top plates be installed in conventional light-frame construction?

Double top plates are crucial in conventional light-frame construction as they help to provide structural integrity, support for the roof, and enhance the overall stability of the walls. Their installation is critical at both corners and intersections with other partitions.

At corners, double top plates ensure that the wall framing is securely tied together, providing greater resistance to lateral forces, such as wind. This is especially vital in maintaining the structural integrity of the building.

At intersections with other partitions, the double top plate serves a similar purpose. It helps to distribute loads more evenly and maintains alignment between adjoining walls. This component is essential for ensuring a flush ceiling and for providing adequate support for the roof framing or any additional loads.

Thus, the requirement for double top plates at both corners and intersections is central to maintaining the strength and stability of the structure. This is why the option indicating that double top plates must be installed at both locations is the correct answer.