Balloon framing is an older style of framing that was the first evolution of the type of house framing we typically see today. Prior to balloon framing, heavy timber construction was common. Balloon framing was the first evolution of heavy timber framing into the 2x members we see today. Modern framing is typically constructed with platform framing which is different from balloon framing. Balloon framed structures are typically between 75 and 175 years old.
The main difference between platform and balloon framing is that the exterior wall studs in balloon framing are the full height of the structure and the floor joists are then attached to the studs or to a ledger on the studs. In platform framing, the exterior wall studs stop at the first floor, with a top plate installed on top of them. The first-floor floor joists are then installed on top of the plate and successive floors continue to be added. If making significant modifications to the structure, it is important to know if the structure is balloon framed, as this may affect what can and cannot be done with modifications to the structure.