Balloon framing: Balloon framing is a system of wood-frame construction, first used in the 19th century, in which the studs are continuous from the foundation sill to the top wall plate. Floor structures (one, two, or more) are hung from the studs. Balloon framing, which replaced post-and-beam construction, was made possible by the availability of structural lumber sawed to uniform sizes. A balloon frame, which is held together entirely by nails, could be erected faster than a post-and-beam frame, with the use of less-skilled labor; and the end result was stronger and more apt to be square and plumb. Balloon frames have one serious drawback: unless firestops are installed at the level of every floor, the stud spaces form what are essentially chimneys from cellar to attic, greatly accelerating the spread of fire. (Compare: platform framing; post-and-beam.)