Which framing method uses 4-inch or 6-inch nominal width members that span between girders or walls?

The correct answer is plank-and-beam framing. This method is characterized by the use of large, solid members such as timber beams that span between girders or walls, with floor or roof decking laid over them. The nominal width of 4-inch or 6-inch members indicates the size of the framing elements typically used in this system, providing a sturdy structure that is capable of supporting significant loads.

Plank-and-beam framing is commonly employed in certain types of residential and commercial construction, allowing for open floor plans and providing flexibility in design. The beams support the planks, which can be made of wood or engineered materials, creating a structural system that is both effective and efficient.

In contrast, other framing methods like joist framing typically rely on closely spaced joists that are smaller in size and are specifically designed to span shorter distances. Platform framing refers to a method where each floor is built as a platform supported by walls, which allows for easier construction and is prevalent in modern wood frame construction. Lightweight I-shaped joists, on the other hand, use engineered wood components designed for rapid construction and efficient load-bearing but differ in structural application and member dimensions from plank-and-beam systems.