Cripple Walls and Balloon Framing Retrofits
Unlike a standard cripple wall which uses platform framing, balloon framing retrofits must be done without cripple wall top plates. In our video on cripple wall retrofits we talk a lot about top plates. Split level homes such as the one shown above, which were common in the thirties and forties, almost always have balloon framing. This is because the main lower floor is nailed to the side of the garage wall. In other words, first they built the garage with the room above it, and then nailed the floor of the main house to the side of it. We also find it in many homes that are not split level built before 1920. Where the main floor attaches to the garage you will normally find balloon framing.
Balloon framing comes in many configurations and requires very specialized retrofit techniques that cannot be found in any of the available retrofit guidelines. Below are some images that show the difference between common cripple wall framing and balloon framing. Notice how the image on the right does not have a top plate.
How Should Balloon Framed Cripple Walls Be Retrofitted?
Houses that need balloon framing retrofits will have floor joists that are both parallel to the balloon framed cripple wall on two of the cripple walls, and the joists will be at right angles on the other two walls. Along the shorter foundations of a rectangular building this is the way the cripple walls are retrofitted.
For balloon framed cripple walls along the long foundations,