What defines a platform frame structure?

A platform frame structure is defined by its construction method, where each floor is built upon a separate platform that rests on the walls of the level below it. This means that the wall framing for each level is completed independently, creating a distinct floor-to-wall connection. This technique provides structural stability and allows for the simple and efficient assembly of multi-story buildings.

In contrast, wall studs that extend to the roof are characteristic of balloon framing, which is different from platform framing. The materials used in a platform frame structure can vary and do not need to be non-combustible; many platform frames are constructed using wood, which is combustible. Heavy timber is also a building style distinct from platform framing, as it typically involves larger and heavier wooden beams not used in standard platform construction. This understanding of the specific characteristics of platform framing is crucial for fire investigators and anyone involved in the construction and safety assessments of buildings.