Definitions for "Platform Framing"
Keywords:  subfloor, joists, stud, balloon, story
Platform framing has been the most common system of wood-frame house construction since the middle of the 20th century. In platform framing, the first structure built on top of the foundation is the first floor. The builders then use this floor as a platform on which to fabricate the first tier of stud walls. These are then erected and the next floor platform built on top of them, and so on, until finally the roof joists and rafters are put in place atop the final tier of walls. Advantages of this system over the earlier balloon-framing system are: smaller and cheaper pieces of lumber can be used in the walls; there is always something solid on which to stand while erecting the next higher part of the building; the walls can be fabricated down on the platform, which increases safety and reduces labor cost; and no added fire-stopping is necessary because each floor platform encloses the stud spaces above and below.
A system of framing of a structure in which the wall studs are attached to the sole plate and top plate. This wall section is attached to the subfloor and floor joists. Each stud wall is only one story high.
A framing method that involves building a plywood floor platform on which the walls are erected. Less common is "balloon framing," in which the wall studs extend below floor level, where they are attached directly to the mudsill.