Framing a free-floating helical staircase takes special planning. In this video, Matt Risinger, master builder, demonstrates how this staircase that looks like a DNA sequence is actually built. Moving from the first to the second floor on the staircase, there are curved treads and risers framed with 1.125" Advantech. The studs are located on the curve. Making a pencil mark on the floor, studs are framed as if it was a base plate, so we could then hang the treads and risers off of that. This is actually the secret sauce, approximately 20 layers of glued and nailed bendable plywood. After the glue and layering, it is pin nailed and finally large structure timber locks screws are run through it. What is holding the staircase up is 4X4 tube steel in an F shape, bolted down through concrete so that the landings are supported.The framers did an amazing job of using bendable plywood, bringing in the curved shape all the way up. At the plaster stage, layers of bendable sheetrock are hung, which will be plastered over resulting in one beautiful, smooth monolithic piece. While under construction, temporary sail rails are used for safety.
